Patent Publication Number: US-7717221-B2

Title: Throttle linkage for a model vehicle

Description:
RELATED APPLICATIONS 
   This application claims the benefit of priority under 35 U.S.C. 120 of provisional patent application Ser. No. 60/669,664 entitled “MOTOR OPERATED VEHICLE,” filed on Apr. 7, 2005. This application is also a continuation in part of U.S. patent application Ser. No. 11/102,008 entitled “A MODEL VEHICLE SUSPENSION CONTROL LINK,” filed on Apr. 7, 2005 now abandoned and previously incorporated as an Appendix of the aforementioned provisional patent application, the contents of which are hereby incorporated by reference in full as if fully set forth herein. This application is also a continuation-in-part of U.S. design patent application Ser. No. 29/227,305 entitled “VEHICLE MOUNTED COIL SPRING AND SHOCK ASSEMBLY” filed on Apr. 7, 2005, now U.S. Pat. No. D, 567,886, the contents of which are hereby incorporated by reference in full as if fully set forth herein. 

   FIELD OF THE INVENTION 
   The present invention relates to vehicle design and has particular application is the design of remote control and model vehicles. 
   Appendices 
   Also attached and made a part of this application are Appendices A-C. Appendix A is a document entitled “Model 5310 Revo Owner&#39;s Manual” and describes in further detail the construction and operation of an embodiment of the invention. Appendix B are documents entitled “Traxxas Service and Support Guide” and “Revo Part List,” which describe in further detail the construction and assembly of components employed in an embodiment of the invention. Appendix C is a document entitled “Revo Suspension Claims,” which describes “progressiveness” in further detail as related to motion ratios and the change in motion ratio. 
   These Appendices are incorporated by reference in this application in their entireties to the same extent as if fully set forth herein. 
   BACKGROUND OF THE INVENTION 
   Vehicles in a variety of styles and sizes have been made for many years. However, despite improvements in design of vehicles over the years, vehicles remain unduly expensive to construct, expensive to maintain. Furthermore, vehicles, in particular, remotely controlled vehicles such as models and other reduced-size vehicles, do not have optimum handling characteristics and are unduly difficult to adjust to obtain optimum handling characteristics under different driving conditions. 
   Accordingly, it is an object of the present invention to overcome the foregoing limitations of the prior art. 
   SUMMARY OF THE INVENTION 
   These and other objects and advantages are achieved in accordance with an embodiment of the present invention, wherein a throttle linkage for a vehicle engine is provided comprising a vehicle engine and a throttle actuation arm secured for pivotal movement about an axis substantially fixed relative to the engine, the throttle actuation arm having an axis extending from the pivotal axis. A throttle control arm extending from the engine and capable of actuation to adjust engine power is also provided, the throttle arm having an axis extending from a point of connection to the throttle and substantially intersecting the throttle actuation arm axis, along with a coupling for engaging the throttle control arm and throttle actuation arm at approximately the point of intersection of their respective axes, the coupling allowing sliding of the arms along their respective axes, relative to each other. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which: 
       FIG. 1  is in isometric view of a portion of the vehicle showing an engine mount supporting an engine on a chassis, wherein the engine is coupled to a transmission assembly; 
       FIGS. 2A  through E illustrate an engine mount allowing adjustment of the center distance between the engine crankshaft and the transmission input shaft or engagement and disengagement of a vehicle engine with a transmission; 
       FIGS. 3A  and B are respectively a partial section view, taken along the section lines of  FIG. 2B , and in isometric view of a partial section view; 
       FIGS. 4A  through C are top, front elevation and side views of that portion of the vehicle chassis on which the engine and transmission are mounted; 
       FIG. 5  is a partial section view of the engine and any amount, taken along the section lines of  FIG. 4B ; 
       FIGS. 6A  through D are isometric, front elevation, side, and top views of an engine and throttle link assembly of a vehicle; 
       FIG. 7  is a detail perspective view of a portion of the throttle link assembly illustrated in  FIG. 6A ; 
       FIG. 8  is a partial section view of the throttle link assembly, taken along the section lines of  FIG. 6C ; 
       FIGS. 9A  through D are perspective, front elevation, side and top views of a front portion of the vehicle, on which is mounted a bumper assembly; 
       FIG. 9E  is a section view, taken along the section line of  FIG. 9C ; 
       FIG. 10  is a perspective view of a vehicle chassis with the body shell removed; 
       FIG. 11  is a sectional view of the vehicle chassis of  FIG. 10 , taken through the portion of the vehicle chassis including the fuel tank, filler cap and finger pull tab, with the cap open, along the line  10 - 10 ; 
       FIG. 12  is a perspective sectional view of a vehicle chassis, with the body shell installed, taken through the portion of the vehicle chassis including the fuel tank, filler cap and finger pull tab, with the cap open, and showing one half of the opening through with the finger pull tab can pass when the body shell is installed or removed; 
       FIG. 13A  is a plan view of the fuel tank, filler cap and finger pull tab, with the cap open; 
       FIG. 13B  is a side view of the fuel tank, filler cap and finger pull tab, as viewed from the rear of the vehicle, with the cap open; 
       FIG. 13C  is a perspective view of the fuel tank, filler cap and finger pull tab, with the cap open; 
       FIG. 13D  is a side plan view of the fuel tank, filler cap and finger pull tab, as viewed from the right side of the vehicle, with the cap open; 
       FIG. 14  is a partially sectional view of the fuel tank, filler cap and finger pull tab, taken along the line  14 - 14 , with the cap open; 
       FIG. 15  is a perspective sectional view of a vehicle chassis, with the body shell installed, showing the cap opened; 
       FIG. 16  is a plan view of a vehicle chassis with the body shell and suspension components removed; 
       FIG. 17  is a sectional view of the vehicle chassis of  FIG. 16 , taken along the line  16 - 16 , with a detail circle K around the secured double looped fuel line in accordance with an embodiment of the present invention; 
       FIG. 18  is a perspective view of the vehicle chassis of  FIGS. 16 and 17 , showing the secured double looped fuel line; 
       FIG. 19A  is a detailed perspective view showing the secured double looped fuel line; 
       FIG. 19B  is a detailed cross-sectional view taken within the detail circle of  FIG. 17 , showing a cross-section of the secured double looped fuel line as secured in its chassis mount; 
       FIGS. 20A  through C are front, side in perspective views of a slipper clutch assembly for use in a vehicle; 
       FIGS. 21A  and B are exploded in perspective views of the slipper clutch assembly; 
       FIG. 22  is a section view, taken along the section lines of  FIG. 20A ; 
       FIG. 23  is an enlarged detail illustration of a portion of  FIG. 22 ; 
       FIG. 24  is a partial section view of the slipper clutch assembly; 
       FIG. 25A  is an axial view, looking along the axis of the brake disk from the outboard side, of a brake pad support assembly in accordance with one embodiment of the present invention; 
       FIG. 25B  is a side view of the brake pad support assembly depicted in  FIG. 25A ; 
       FIG. 25C  is a plan view of the brake pad support assembly depicted in  FIG. 25A ; 
       FIG. 25D  is a perspective view of the brake pad support assembly depicted in  FIG. 25A , as viewed from the outboard side; 
       FIG. 26A  is a sectional view of the brake pad support assembly depicted in  FIG. 25A , taken along the line  25 A- 25 A of  FIG. 25A ; 
       FIG. 26B  is a sectional perspective view of the brake pad support assembly depicted in  FIG. 25D , taken along the line  25 D- 25 D of  FIG. 25D ; 
       FIG. 27  is an exploded perspective view of an embodiment of the brake pad support assembly and base, as viewed from the outboard side; 
       FIG. 28  is an exploded perspective view of an embodiment of the brake pad support assembly and base, as viewed from the inboard side; 
       FIGS. 29A  through D are rear elevation, side, top and perspective views of a front bulkhead assembly and suspension arm assembly of the vehicle; 
       FIGS. 30A  through D are front elevation, side, top and perspective views of a telescoping drive shaft of the vehicle; 
       FIGS. 31A  and B are section and perspective section views, taken along the section lines  31 - 31  of  FIG. 30A , of the telescoping drive shaft; 
       FIGS. 32A  and B are section and perspective section views, taken along the section lines  32 - 32  of  FIG. 30A , of the telescoping drive shaft; 
       FIGS. 33A  through D are rear elevation, side, top and perspective views illustrating coupling of the drive shaft to an axle assembly supporting a wheel of the vehicle; 
       FIG. 34  is a section view, taken along the section lines  34 - 34  of  FIG. 33C , illustrating coupling of the drive shaft to an axle assembly supporting a wheel of the vehicle; 
       FIG. 35  is a perspective section view, taken along the section lines  35 - 35  of  FIG. 33C , illustrating coupling of the drive shaft to an axle assembly supporting a wheel of the vehicle; 
       FIG. 36  is a section view substantially bisecting the ball joint and axle carrier assemblies of the vehicle; 
       FIG. 37  is a side view of the axle carrier shown in  FIG. 36 ; 
       FIG. 38  is a perspective exploded view of the axle carrier showing a sealing boot secured to the carrier; 
       FIGS. 39A  through C are front elevation, side and top views of the axle carrier shown in  FIG. 38 ; 
       FIG. 40A  is view of the front portion of the vehicle, with the chassis removed for clarity, showing the dual servos and center dual arm steering arm, viewed from underneath; 
       FIG. 40B  is view of the front portion of the vehicle, with the chassis removed for clarity, showing the dual servos and center dual arm steering arm, viewed from the front end of the vehicle; 
       FIG. 40C  is view of the front portion of the vehicle, with the chassis removed for clarity, showing the left side front wheel and left side servo and the center dual arm steering arm, viewed from the left side of the vehicle; 
       FIG. 40D  is a perspective view of the front portion of the vehicle, with the chassis removed for clarity, showing the dual servos and center dual arm steering arm, viewed from underneath the left side of the vehicle; 
       FIG. 41A  is an exploded perspective view of the components of the dual servos and center dual arm steering arm assembly, as viewed from above the vehicle; 
       FIG. 41B  is an exploded perspective view of the components of the dual servos and center dual arm steering arm assembly, as viewed from below the vehicle; 
       FIG. 42  is a perspective view of the dual servos and center dual arm steering arm assembly, with the other components of the front end of the vehicle removed for clarity, viewed from the rear left side of the vehicle; 
       FIG. 43A  is a plan view of a steering servo mounted on the right side of the chassis; 
       FIG. 43B  is a side view of a steering servo mounted on the right side of the chassis; 
       FIG. 43C  is a perspective view of a steering servo mounted on the right side of the chassis; 
       FIG. 43D  is an end view of a steering servo mounted on the right side of the chassis, viewed from the front of the vehicle; 
       FIG. 44  is a sectional view of the mounted steering servo of  FIG. 42A , taken along the line  41 A- 41 A; 
       FIG. 45  is a perspective view of a steering servo mounted on the right side of the chassis, and shows a front one of the mounting brackets; 
       FIG. 46  is an exploded perspective view of a steering servo, front and rear mounting brackets, and the portion of the chassis to which the steering servo is mounted; 
       FIGS. 47A  and B are side and top plan views showing the layout of various components supported by the vehicle chassis; 
       FIG. 48  is a perspective view of a vehicle chassis alone; 
       FIGS. 49A  through D are side, front, top and perspective views of the vehicle chassis supporting certain components of a vehicle; 
       FIGS. 50A  and B are section and perspective section views, taken along section lines of  FIG. 49C , illustrating the shape of the chassis and relative location of certain components supported by the chassis; 
       FIGS. 51A  and B are section and perspective section views, taken along section lines of  FIG. 49C , illustrating the shape of the chassis and relative location of certain components supported by the chassis; 
       FIG. 52  he is a section view, taken along section lines of  FIG. 49C , illustrating the shape of the chassis and relative location of certain components supported by the chassis; 
       FIG. 53 , depicts a perspective view of the front suspension assembly for the left front wheel; 
       FIGS. 54A-E  show detailed views of the axle carrier, pin and pivot link with various predetermined combinations of ring-shaped spacers; and 
       FIG. 55  is a table depicting an example of five different positionings of the pivot link for different combinations of caster angle and roll center settings, employing a thick spacer and a thin spacer in different configuration, as well as a standard configuration employing a tall center hollow ball type pivot link. 
       FIG. 56  is an exploded perspective view of the front left suspension assembly of the vehicle; 
       FIGS. 57A  through D are front elevation, side, top and perspective views of the front left suspension assembly of the vehicle in a full bump position; 
       FIGS. 58A  through D are front elevation, side, top and perspective views of the front left suspension assembly of the vehicle in a full droop position; 
       FIG. 59  is a dimensioned front elevation of the front left suspension assembly of the vehicle, shown at ride height; 
       FIG. 60  is a dimensioned rear elevation of the rear left suspension assembly of the vehicle, shown at ride height; 
       FIG. 61  is a dimensioned top view of the chassis of the vehicle showing the front and rear left suspension assemblies of the vehicle; 
       FIGS. 62  A and B are top and side views of a rocker arm employed in a rear suspension assembly of the vehicle; 
       FIGS. 63  A and B are top and side views of a rocker arm employed in the front suspension assembly of the vehicle; and 
       FIG. 64  is top view of a portion of the front left suspension assembly of the vehicle showing the damper and rocker arm employed therein. 
   

   DETAILED DESCRIPTION 
     FIG. 1  illustrates a vehicle engine  500  supported by an engine mount  510  (partially shown) on the vehicle chassis  300 . The engine  500  drive shaft  512  rotates a clutch bell  514  and drive gear  516  assembly that is coupled via a spur gear  518  to a transmission assembly  520 . The engine mount  510  is configured to allow generally vertical movement, shown by the arrows  522 , to accommodate drive and spur gears  516 ,  518  of different sizes or to allow engagement and disengagement of a vehicle engine with a transmission. Such gear mesh adjustment, in a generally vertical direction, reduces horizontal space needed on the chassis  300  and accommodates the multi-level design of the chassis  300 . 
   Referring now to  FIGS. 1 ,  2 A through E,  3 A and B and  4 A through C, the adjustable engine mount  510  is shown in more detail. The engine mount  510  comprises a front support  524 , a middle support  526  and a rear support  528 . The supports  524 ,  526  and  528  are preferably manufactured from cast aluminum; however, other suitable materials having the required strength and temperature resistance would also be suitable. The front and rear supports  524 ,  528  are generally rib-shaped and are secured on the chassis  300  by outboard flanges  530  and inboard flanges  532 . Bolts  534  are inserted into threaded apertures  535  formed in the flanges  530 ,  532  from and through the bottom of the chassis  300 . The middle support  526  is pivotally mounted to the front and rear supports  524 ,  528  by a pivot bolt  536  extending through a hinge aperture  538  of a middle support  526  and aligned apertures  540 ,  542  through the front and rear supports  524 ,  528  respectively. The pivot bolt  536  comprises a threaded end  554 , but preferably has a smooth surface that extends through the hinge aperture  538 . The threaded end  554  secures the pivot bolt  536  to a threaded shank  546  extending laterally from and in alignment with the aperture  540  of the front support  524 . The smooth surface of the pivot bolt  536  reduces friction, thereby facilitating pivoting of the middle support  526  between the front and rear supports  524 ,  528 . 
   The middle support  526  includes a pivot arm  547  extending generally downwardly and inboard from the remainder of the support  526 . The pivot arm  547  positions the hinge aperture  538  so as to impart a horizontal component to the pivotal movement of the engine  500  when the middle support  526  is pivoted from the lowest to the uppermost position. The rotational axis of the drive gear  516  is offset in the outboard direction from the rotational axis of the spur gear  518 . Thus, the horizontal component of movement of the engine  500  as the middle support  526  pivots upwardly, moves the drive gear  516  axis more directly toward the spur gear  518  axis than would otherwise be the case, facilitating meshing of the gears with reduced interference. The pivot arm  547  also positions the hinge aperture  538  inboard, to impart greater movement of the engine  500  as the middle support  526  is pivoted. The pivot arm  547  is formed from a plurality of structural ribs  549 , to reduce the weight of the middle support  526 . 
   Setting of the position of the engine mount  510  is accomplished by an adjustment bolt  546 , which extends through an aperture  548 , an adjustment slot  550  and an aperture  552 , through the respective rear support  528 , middle support  526  and front support  524 . The adjustment slot  550  is located near the outboard end of the middle support  526 , for ease of access and clearance from the engine  500 . A lock washer (not shown) is positioned over the adjustment bolt  546 , between the surfaces of the rear and middle supports  528 ,  526  and between the services of the middle and front supports  526 ,  524 , to secure the surfaces against relative movement when the adjustment bolt  546  is tightened. The adjustment bolt  546  comprises a threaded end  554 , but preferably has a smooth surface that extends through the adjustment slot  550 . The threaded end  554  secures the adjustment bolt  546  to a threaded shank  556  extending laterally from and in alignment with the aperture  552  of the front support  524 . The smooth surface of the adjustment bolt  546  reduces friction, thereby facilitating pivoting of the middle support  526  between the front and rear supports  524 ,  528 . 
   The engine  500  is supported by inboard and outboard engine support surfaces  558 ,  560  formed on the engine mount  510  middle support  526 . Threaded engine fastening bores  562  are formed through the support surfaces  558 ,  560 , to receive threaded engine fastening bolts  564 . The fastening bolts  564  are tightened into the engine fastening bores  562  and through outboard and inboard flanges  566  extending laterally from the engine  500 , to secure the engine  500  to the pivotable middle support  526  of the engine mount  510 . The engine mount  510  is generally U-shaped between the engine support surfaces  558 ,  560 , to receive the lower end of the engine  500 . 
   In use, the engine mount  510  may be employed to position the engine  500  drive gear  516  toward and away from the spur gear  518 . The adjustment bolt  546  is loosened, allowing the outboard end of the middle support  526  of the engine mount  510  to be pivoted to a desired position, about the pivot bolt  536 , parting the drive gear  516  and the spur gear  518 . The middle support  526  acts as a hinge relative to the chassis  300  and the transmission assembly  520 , which is fixed to the chassis  300 . The range of pivotal movement of the middle support  526  is determined by the length of the adjustment slot  550 . The length of the adjustment slot  550  is determined, primarily based on the variety of teeth or sizes of the drive gear  516  and spur gear  518 . The centerline of the adjustment slot  550  substantially tracks a constant radius from the pivot bolt centerline  536 , to allow pivotal movement of the middle support  526  without substantial interference between the surfaces of the adjustment bolt  546  and the adjustment slot  550 . Once substitution of a different sized drive gear  516  or spur gear  518  is made, or other modifications or maintenance is completed, the engine  500  is pivoted upwardly to mesh the drive gear  516  and spur gear  518 , connecting the engine  500  to the transmission assembly  520 . The adjustment bolt  546  is then tightened, securing the middle support  526  in the desired position for operation of the vehicle engine  500  and transmission assembly  520 . 
   Referring now to  FIGS. 6A  through D,  7  and  8  a throttle link assembly  600  is shown that accommodates vertical movement of the engine  500  by the engine mount  510  without being uncoupled from the engine  500 . The throttle link assembly  600  is mounted to the middle support  526  of the engine mount  510 , for movement with the engine  500  and the throttle arm  602  extending downwardly from the engine throttle  604 . The middle support  526  includes a throttle link support surface  606  (shown in  FIGS. 1 through 3B ) extending towards the front of the vehicle. The throttle link support surface  606  includes a threaded aperture into which is threaded a throttle link bolt  608 , securing the throttle link assembly  600  for pivotal movement about an axis generally perpendicular to the throttle link support surface  606 . 
   The throttle link assembly  600  includes a bell crank  610  secured for pivotal movement about the bolt  608 , to actuate the throttle arm  602  in response to actuation of a servo-link  612 . The bell crank  610  includes a central cylindrical shaft  614 , through which the bolt  608  extends. The bell crank  610  pivots about bolt  608 . A servo-link arm  616  and a throttle actuation arm  618  extend in substantially perpendicular directions from bell crank  610 . The servo-link  612  and the throttle arm  602  are both pivotally connected to the servo-link arm  616  and the throttle actuation arm  618 , respectively. The servo-link  612  is preferably manufactured from a length of steel wire, which is bent into an aperture  620  formed through the servo-link arm  616  and secured for pivotal movement. 
   The throttle actuation arm  618  is positioned higher than the servo-link arm  616 , to provide clearance from the servo-link  612  when the engine throttle  604  is actuated towards an open position. A slot  622  is formed through the throttle actuation arm  618 , to allow the throttle arm  602  to travel in a relatively straight line of motion as the throttle actuation arm  618  rotates about the throttle link bolt  608 . The slot  622  is open at the distal end of the actuation arm  618 , to allow the throttle arm  602  to be easily removed. The slot  622  also allows the engine  500  to be removed from the vehicle without disrupting the throttle link assembly  600 , which is secured to the engine mount  510 , rather than to the engine  500 . 
   The throttle  604  is actuated to an open position by servo-link  612  pushing against the servo-link arm  616 , rotating the bell crank  610  to move the throttle actuation arm  618  towards the servo-link  612 . The servo-link  612  is secured by a guide  624  and stop  625  to a servo actuation arm  626  of a servo mechanism  613 . The guide  624  allows the servo-link  612  to slide, while the stop  625  clamps the servo-link  612 , preventing further sliding nearer the throttle  604 . 
   The servo mechanism  613  rotates the servo actuation arm  626  about a servo mounting aperture  628  to move the actuation arm  626  towards the bell crank  610 . The servo actuation arm  626  slides along the servo-link  612  until the guide  624  abuts the stop  625 , at which point, continued movement of the actuation arm  626  pushes the servo-link  612  to actuate the bell crank  610 . As the bell crank  610  actuates, the throttle actuation arm  618  moves towards the servo-link  612  and the throttle arm  602  follows, opening the throttle  604 . The guide  624  allows the servo actuation arm  626  to be actuated in an opposite direction, such as to actuate a braking mechanism (not shown), while leaving the throttle  604  and the throttle link assembly  600  in the engine idle position (closed) shown. A spring  615  connected between an enclosure  617  holding the servo and the end of the servo-link  612  extending out of aperture  620  of the bell crank  610  returns the throttle  604  and a throttle link assembly  600  to the engine idle position. 
   The configuration and position of the throttle link assembly  600  and the servo actuation arm  626  allow adjustment of the position of middle support  526  of the engine mount  510  and the engine  500 , without requiring decoupling of the throttle link assembly  600  from the engine or the servo actuation arm  626 . Contributing to this is that the pivot points of the bell crank  610  and servo actuation arm  626  (excepting the pivot point at the throttle arm  602 ) form a substantially rectangular configuration in the unactuated position shown in  FIG. 6D . When actuated, the pivot points form a trapezoid. In addition, the axis of the servo-link  612  is substantially perpendicular to the axis of rotation of the bell crank  610  about the bolt  608 . Thus, adjusting the position of the engine  500  by the engine mount  510  does not require adjustment of the throttle control link assembly  600 . 
     FIGS. 9A  through E illustrate a bumper assembly  650  that cooperates with a skid plate  652  to protect the front end of the vehicle shown from impacts. It will be apparent that the bumper assembly  650  may also be mounted on the rear end of the vehicle, to protect the back of the vehicle from impacts as well. The bumper assembly  650  comprises a bumper support  654  and a bumper  656  that are secured to a bumper chassis mount  658  attached to the vehicle chassis  300 . Below the bumper assembly  650  and mounted to the bulkhead assembly  658  is the skid plate  652 . 
   Referring additionally to  FIG. 9E , the bumper support  654  is formed in a generally oval-shape loop and is mounted to the bulkhead assembly  658  in a horizontal orientation relative to the chassis  300 . The inboard length  670  of the bumper support  654  includes two integrally formed mounting collars  672  extending vertically across the width of the bumper support  654 . The mounting collars  672  are longer than the width of the bumper support  654 , to provide greater resistance to and strength during vertical flexing and twisting of the bumper support  654 . The mounting collars  672  extend vertically, to avoid interference with flexing of the inboard length  670  of the bumper support  654 . A pair of fastening bolts  673  extending through the mounting collars  672  and portions of the bulkhead assembly  658  secure the bumper support  654  to the front of the vehicle. The bumper support  654  also includes C-shaped, curved lateral ends  674 , each of which act as a curved leaf spring. The mounting collars  672  are positioned to allow inboard deflection of the lateral ends  674 . The outboard length  676  of the bumper support  654  extends between the lateral ends  674  and bends in a slightly convex curve relative to the bumper  656 . The inboard and outboard lengths  670 ,  676  of the bumper support  654  also act as leaf springs to absorb an impact. The outboard length  676  of the bumper support  654  includes two integrally formed mounting collars  678  extending horizontally and outwardly from the front of the bumper support  654 . The mounting collars  678  preferably extend outwardly from the outboard length  676  of the bumper support  654  a sufficient distance to maintain clearance between the surfaces of the bumper  656  and the bumper support  654  in extreme impact conditions, when maximum deflection of the components occurs. The bumper support  654  is preferably manufactured from a strong, elastic plastic, such as super tough Nylon® (Zytel ST 801), available from DuPont. 
   The bumper  656  is secured to the mounting collars  678  by a pair of fastening bolts  680 . The bumper  656  includes a frame member  682 , surrounding a middle section of the length of the bumper  656 . The frame member  682  adds rigidity and strength to the middle section of the bumper  656 , as well as supporting a pair of substantially parallel, horizontally extending bumper stays  684 . The outboard lengths of the bumper stays  684  each act as leaf springs to absorb an impact. The bumper  656  is formed in a generally convex curve facing the front of the vehicle, to aid in deflecting the vehicle away from objects upon impact and to aid in deflecting movable objects from the path of the vehicle. The rear bumper can be flat, which is more stable for wheelies. The bumper  656  is preferably manufactured from a strong, elastic plastic, such as super tough Nylon® (Zytel ST 801), available from DuPont. 
   The skid plate  652  is generally rectangular in shape, is substantially uniform in thickness and is secured to and extends forwardly from the bulkhead assembly  658 . The skid plate  652  is positioned below and rearward of the bumper  656 , and extends upwardly from the bulkhead assembly  658  toward the lower edge of the bumper  656 . This orientation causes the front surface of the skid plate  652  to face forwardly and downwardly, to deflect obstacles away from the vehicle and to lift the vehicle&#39;s front end upwardly over obstacles in the path of travel. The skid plate  652  acts as a leaf spring to absorb and protect the front end and bulkhead assembly  658  from impacts. Sufficient clearance is provided between the upper edge of skid plate  652  and the bumper  656 , to avoid interference as the skid plate  652  flexes. The skid plate  652  is preferably manufactured from a strong, elastic plastic, such as super tough Nylon® (Zytel ST 801), available from DuPont. 
   In use, the bumper assembly  650  is capable of extreme deflection upon impact. The outboard length  676  of the bumper support  654  will deflect into contact with the inboard length  670 , if necessary, on impact. The lateral ends  674  will deform into a smaller radius, upon impact, while both the inboard and outboard lengths  670 ,  676  will deform or bow inwardly toward the center of the bumper support  654 . Deflection of the outboard length  676  of the bumper support  654  allows total deflection of the bumper support  654  in inboard direction greater than the deflection of the lateral ends  674 . The bumper support  654  will elastically return to substantially the same position and shape following impact. The stays  684  of the bumper  656  will also elastically deflect rearwardly, into a more bowed shape, upon impact. Following impact, bumper stays  684  will substantially return to the original shape. 
   Turning now to  FIGS. 10-15 , and initially to  FIG. 10  thereof, a perspective view of a vehicle chassis  300  with the body shell  850  removed is depicted, from the right side of the vehicle chassis  300 . Vehicle chassis  300  has a fuel tank  852  secured thereon. Fuel tank  852  has a fill opening  854  and a hinged filler cap  856 . In one embodiment, the fill opening  854  has a rim  855  tipped toward a lateral side of the body shell  850 , at an angle with respect to the horizontal plane. In one embodiment, this angle is between about 10 degrees and 80 degrees and more preferably between about 40 degrees and 50 degrees. By making the opening  854  at an angle, the opening is more easily accessible for the outside of the body shell  850  for filling. Furthermore, placing the opening  854  at an angle allows the fill opening  854  to be placed at the side of the body shell  850 . The angle permits a fuel filler bottle nozzle to be inserted into the opening  854  without turning the bottle upside down over the vehicle, which reduces spillage. Furthermore, the angle makes the fuel cap easier to open by means of a direct upward pull on a finger ring pull, in a manner to be described below. 
   The angle also allows greater freedom of body shell styles since a vertical opening would require a fuel neck extension to accommodate taller body shell styles, such as SUV styles, or some other cumbersome method of refueling. However, with the angled opening, many body shell styles of different heights can be used on the same chassis, without changing the fill opening  854  or adding a fuel neck extension. 
   During fueling, air often becomes entrained in the fuel as it is squeezed into the tank, causing bubbles. These bubbles can cause foam and “burping” during filling, resulting in spills. To minimize this problem, the fuel tank  852  can include channels  853  along the inside upper surface of the top wall of the fuel tank  852 , sloped upwardly leading to the inside of the opening  854 . These channels allow a path for entrained air in the tank to escape, toward the inside edges of opening  854 , where the escaping air is less likely to cause foaming or “burping” during filling. 
   The fuel tank  852  can have a resiliently closeable cap, such as a hinged fuel cap  856 . Fuel cap  856  can be pivotably attached to molded eyes  857  of the top of fuel tank  852  and attached with hinge pins  864 . A spring  866  can be installed between the fuel cap  856  and the tank  852  to resiliently urge fuel cap  856  into a closed position when it is not being intentionally physically opened for filling. The cap can also be closed by a clip that snaps over the opposing end of the cap from the hinge and maintains the cap closed position. 
   Fuel cap  856  also includes a nozzle  858  to which is attached one end of a pressurization tube  860 . The other end of pressurization tube  860  leads to a nozzle  861  on exhaust muffler  882 . During operation of the engine  500 , a slight amount of back pressure will be present in exhaust muffler  882 . Pressurization tube  860  causes this back pressure to pressurize fuel tank  852 , thus assisting fuel flow without the need to rely on gravity alone and without the need for fuel pumps. 
   A finger pull tab  868  having an elongated shaft member  870  is attached to the fuel cap  856 . This pull tab  868  permits an operator to open the fuel cap  856  while keeping the users hands at a safe distance from hot or rotating objects that could injure them. This is advantageous because, after operation, the fuel cap can be soaked with fuel and sufficiently hot to risk injury from touching the fuel cap or, at the least, an unpleasant burning sensation. 
   In accordance with an embodiment of the present invention, the fuel cap  856  can be opened and closed, and the tank refilled, without the need to remove the body shell  850 . However, if desired, the body shell  850  can be removed and replaced for access to the fuel tank  852 , or other components on chassis  300 , without the need to either open the cap  856  or to remove the finger pull tab  868 . However, as can be seen if  FIG. 12 , the body shell  850  and the fill opening  876  in the body shell  850  are spaced apart from opening  854  sufficiently so that the cap  856  can be pulled open inside the shell  850  sufficiently to allow insertion of a fuel filling line or nozzle, without removing the body shell  850 . As depicted in  FIG. 12 , opening the cap  856  to an approximately horizontal position is sufficient to provide substantially unimpeded access to the opening  854 , but any degree of opening sufficient to allow insertion of a fuel filling line or nozzle will suffice. 
   As can be seen in  FIG. 12 , the cap  856  can be opened by means of pulling up on finger pull tab  868 , which extends through an opening  874  in the body shell  850 . Because  FIG. 12  is a sectional view, only one half of opening  874  is depicted, but it is to be understood that the remainder of the slot (not shown) is substantially a mirror image of the one half of a opening  874  shown. Opening  874  is sized to permit the tab portion  872  of pull tab  868  to pass without undue interference, to permit removal and replacement of the body shell  850  without removal of pull tab  868 . However, since pull tab  868  can be made from a resilient material, such as plastic or rubber, some deformation of tab portion  872  as it passes through opening  874  is permissible. Furthermore, having a separate opening for the finger pull tab  868  provides greater access to the fuel tank opening  854 , since the finger pull tab  868  is safely inside the slot  876 , away from opening  854 , and thus does not interfere with the fuel tank opening  854 . The body shell  850  has a fill opening  876  approximately aligned with the opening  854  in the tank  852 . 
   Turning to  FIGS. 16-18  and  19 A-B, a vehicle chassis  300  having a secured double looped fuel line  800  in accordance with an embodiment of the present invention is depicted. Fuel line  800  has an intake end  802  attached to a nozzle  804  which extends into fuel tank  852 , from which fuel can be withdrawn. Fuel line  800  has an exit end  806  that is attached to a carburetor  898  on engine  500 . Fuel line  800  can be made from any suitable material, including a plastic or rubber material generally resistant to the type of fuel employed. 
   As can be seen in  FIGS. 19A  and B, the middle of fuel line  800  does not run straight between the fuel tank  852  and the carburetor  898 , but rather is coiled into a loop portion  808 . In the event the vehicle turns over during operation, fuel generally can no longer be drawn into the entrance of the fuel line  800 . Accordingly, the engine will soon stop running. Normally, the vehicle will be operated by radio control and the operator may be several hundred feet away from the vehicle at the time the vehicle turns over. Often, this is too far to reach the vehicle to turn it upright before the engine stops. In the present invention, the loop portion  808  of the fuel line will retain additional fuel, giving the operator additional time to reach and right the vehicle before the engine stops running from lack of fuel. It should be understood that, although a double loop is depicted, a single loop or more loops could also be employed. 
   Although the loop portion  808  will retain additional fuel, the coiling of the fuel line undesirably causes the fuel line to attempt to uncoil. Because the fuel line is nearby many hot surfaces, including the engine  500  and exhaust pipe, the fuel line could easily come in contact with these hot surfaces during rough drives. Accordingly, in accordance with the present invention, the double loop is secured to the chassis by upper double clip  810  and lower double clip  812 , which are affixed to a support member such as roll bar  899  which is attached to chassis  300 . 
   With the loop portion  808  secured, the advantages of using the loop portion  808  to provide additional fuel capacity in the fuel line is achieved, without the risk of fuel fires caused by unintended contact between the fuel line and a hot surface. 
   As can be seen in  FIG. 17 , the upper double clip  810  can have a first fastener having a pair of opposed arcuate surfaces to grip a first loop of the loop portion  808  and a second fastener having a pair of opposed arcuate surfaces to grip a second loop of the loop portion  808 . The lower double clip  812  can have a third fastener having a pair of opposed arcuate surfaces to grip a lower portion of the first loop of the loop portion  808  and a fourth fastener having a pair of opposed arcuate surfaces to grip a lower portion of the second loop of the loop portion  808 . At least a portion of one of the opposing surfaces of the third fastener is spaced farther from the other opposing surface to receive and retain the curved surface of a portion of the tube retained by the third fastener. Also, at least a portion of one of the opposing surfaces of the fourth fastener can be spaced farther from the other opposing surface to receive and retain the curved surface of a portion of the tube retained by the fourth fastener. 
   The first and third fasteners can be formed as one integral piece and the second and fourth fasteners can also be formed as one integral piece. Thus, the third fastener can form an entrance for placement of a portion of a tube in the first fastener and the fourth fastener can form at least a portion of an entrance for placement of a portion of a tube in the second fastener. Conveniently, either or both double clips  810  and  812  can be molded integrally with roll bar  899 , which is conveniently made of a plastic material. Because both the fuel line  800  and the double clips  810  and  812  are somewhat resilient, the fuel lines can be resiliently inserted into the clips and resiliently retained there during rough driving, while still being removable intentionally by the operator without difficulty 
     FIGS. 20A-C  through  24  illustrate a slipper clutch assembly  900  for transferring torque from the spur gear  518  shown in  FIG. 1  to a transmission input shaft  902 , during operation of the vehicle. The slipper clutch assembly  900  protects the spur gear  518  and the engine  500  shown in  FIG. 1  from acute shocks to the drive train, such as when the wheels of the vehicle are abruptly slowed from a high speed spin to a much lower rotation when the vehicle lands following a jump. The slipper clutch can also serve as a torque limiting traction control aid. The slipper clutch assembly  900  interposes a friction coupling between the spur gear  518  and the transmission input shaft  902 , which momentarily slips, allowing the spur gear  518  to rotate at a speed faster than the input shaft  902  until the speed is slowed by the friction coupling of the slipper clutch assembly  900 . When acute shocks to the drive train are not experienced, the slipper clutch assembly  900  preferably transmits rotational torque with little or no slippage. 
   The slipper clutch assembly  900  is configured to allow removal of the spur gear  518  without changing the compression setting of the slipper clutch assembly  900 . The spur gear  518  is secured directly to the drive plate  904  by bolts  906  extending through substantially equidistant locations on the body of the spur gear  518 . The bolts  906  are threaded into similarly located receptacles  908  formed on the surface of the drive plate  904 . The spur gear  518  can be removed from the slipper clutch assembly  900 , for service or replacement, by removing the bolts  906  from the receptacles  908 . 
   The slipper clutch assembly  900  transfers torque between the spur gear  518  and the input shaft  902 , depending upon the compressive force applied to the drive plate  904  and the driven plate  910 . The compressive force is adjusted by an adjustment nut  912  threaded on the end of the input shaft  902  extending from the vehicle transmission (not shown). The adjustment nut  912  abuts and compresses a pair of springs  916  mounted on the input shaft  902  to maintain the desired compressive force. Although springs  916  are spring washers, it will be apparent that other suitable springs, such as helical springs and the like, could be employed. The springs  916 , in turn, press a radial ball bearing assembly  918  against the drive plate  904 . The drive plate  904 , in turn, presses clutch pads  920  against a clutch disc  922  held by the driven plate  910  of the slipper clutch assembly  900 . Frictional resistance to movement between the contacting surfaces of the clutch pads  920  and the clutch disc  922  couples the spur gear  518  to the transmission input shaft  902 . The rotational and axial position of the driven plate  910  is secured by a pin  926  that extends through a diametrically extending hole  928  through the transmission input shaft  902 . Opposing ends of the pin  926  extend from the hole  928 , against the driven plate  910  and prevent movement of the plate axially along the shaft  902  away from the adjustment nut  912 . The greater the compressive force applied to the clutch pads  920  and the clutch disc  922 , the more torque will be required to cause slippage of the slipper clutch assembly  900 . 
   The ball bearing assembly  918  supports the spur gear  518  for rotation about the transmission input shaft  902 , in addition to transmitting compressive forces from the spring(s)  916 . An aperture  924  in the center of the spur gear  518  preferably fits snugly over the ball bearing assembly  918 . The ball bearing assembly  918  also fits snugly over the transmission input shaft  902 . This configuration reduces the total clearance encountered between the input shaft  902  and the teeth of the spur gear  518 , reducing the risk of run out by the spur gear  518 . 
   The clutch pads  920  are each supported by a flange  929  extending outwardly from a central, circular body portion of the drive plate  904 . The clutch pads  920  each include a pair of indexing holes  930  in their surfaces opposite the clutch plate  922 . Indexing posts  932  extending from the flanges  929  insert into the indexing holes  930 , secure the clutch pads  920  from sliding out of position during operation. 
   The clutch disc  922  is secured against movement by the driven plate  910  of the slipper clutch assembly  900 . The clutch disc  922  has a circular outer perimeter substantially matching the circular perimeter of the driven plate  910 . However, a central portion is cut from the clutch disc  922  in an irregular pattern, substantially matching a similar pattern  934  extending from the surface of the driven plate  910  toward the drive plate  904 . The perimeter of the irregular pattern cut in the clutch disc  922  fits around the similar pattern extending from the driven plate  910 , to secure the clutch disc  922  for rotation with the driven plate  910 . 
   The driven plate  910  is secured for rotation with the transmission input shaft  902  by the pin  926 , the ends of which engage an opposing pair of slots  936  formed in a collar  938  extending around the input shaft  902  and away from the drive plate  904 . The pin  926  and the slots  936  cooperate to index rotation of the driven plate  910  to the input shaft  902 . Rotation of the driven plate  910  rotates both the pin  926  and the input shaft  902 . 
   Extending from the surface of the driven plate  910  are a number of integrally formed vanes  940 . The vanes  940  trace spiral paths outwardly over the area of the driven plate  910  supporting the clutch disc  922 . As the driven plate  910  rotates, the spiral vanes  940  act as cooling fins to dissipate heat caused by friction between the clutch disc  922  and the clutch pads  920  during operation of the vehicle. 
   The slipper clutch assembly  900  provides reduced size, low inertia and enhanced heat dissipation. These features are provided by use of a semi-metallic, high-friction material to form the clutch pads  920 . Use of such a high-friction material allows placement of the clutch pads  920  closer to the axis of rotation of slipper clutch assembly  900 , reducing the diameter of the slipper clutch assembly  900 . The reduced diameter contributes to both reduced size and low inertia. Both the drive and driven plates  904 ,  910  are preferably manufactured from cast aluminum, which is light-weight and a good heat conductor, further contributing to low inertia and enhanced heat dissipation. 
   In prior model vehicle braking pad assemblies, a thin piece of friction material is supported by a pad support constructed of a thin piece of sheet metal. A small piston, actuated by a cam, applies force to the sheet metal plate. The plate applies force to the friction material and disk. A problem with such prior braking pad assemblies is that the use of thin and flexible material for the pad support and friction material results in poor distribution of pressure, overheating and uneven wear. As a result, the area directly under the piston wears quickly and overheats. 
   In order to overcome these disadvantages of prior model vehicle braking pad assemblies, in an embodiment of the present invention, the friction material can be supported by a very rigid cast pad holder (also called a caliper). The pad holder geometry is more three dimensional than typical pads that are stamped from sheet metal. This structure also provides the caliper with a high thermal capacity and better thermal conductivity for cooling. Furthermore, in an embodiment of the present invention, the caliper can employ an integrated post with ribs providing additional stiffness to help evenly distribute the forces from the actuating cam. In another embodiment, an integrated cam receiving surface on the caliper also helps to evenly distribute the forces from the cam. 
     FIGS. 25A-D ,  26 A-B and  27 - 28  depict a model vehicle braking pad caliber assembly  1000  in accordance with in an embodiment of the present invention. The braking pad caliper assembly  1000  has outboard pad made of a friction material  1002  supported by a very rigid cast pad holder or caliper  1004  on the outboard side of braking disk  1006 . On the inboard side, an embodiment of the invention can include a pad of friction material  1008  supported by an opposing very rigid cast pad holder or caliper  1010  on the inboard side of braking disk  1006 . The braking disk  1006  can be made from strong material, such as steel, aluminum or titanium. The braking disk further can have slots  1001  and holes  1003  for, respectively, reduction of weight and assisting cooling of the disk. The calipers  1008  and  1010  can be made from a strong material, such as steel, aluminum or titanium. In an embodiment, the calipers  1008  and  1010  can be made from cast aluminum, which has a higher thermal conductivity than steel as well as a high strength to weight ratio. 
   Disk  1006  is slidably mounted over drive shaft  1012  but not affixed to it. That is, the disk  1006  is free to slide axially on the shaft  1012  to a limited degree. Drive shaft  1012  has opposite flat surfaces  1013  and  1015  on its end  1011  for receiving a coupling (not shown). The coupling has two pin keys (not shown) that extend into opposite ends  1018  and  1020  of slot  1022 , that extends from hole  1017  in disk  1006 . These pin keys force the disk  1006  to rotate with the coupling, and hence with the drive shaft  1012  but permit a limited degree of axial sliding of the disk  1006  with respect to drive shaft  1012 . 
   As can be seen in  FIG. 27  and  FIG. 28 , in one embodiment, the brake pad support calipers  1004  and  1010  each support a brake pad of friction material  1002  and  1008  on first inner faces  1005  and  1009 , respectively, to which the friction material  1002  and  1008  is disposed. In one embodiment, the calipers  1004  and  1010  can each be a single piece of cast aluminum. 
   In one embodiment, the inboard caliper  1010  has a cam receiving post or follower  1016  extending from its outside face  1045 . The post  1016  has a cam receiving surface for receiving compressive force from an actuating cam  1025 . 
   The actuating cam  1025  can take a variety of forms. In one embodiment, the cam  1025  is the flat surface  1027  of a half-shaft portion of a cam shaft  1023 . The cam shaft  1023  is retained in base  1032  for pivoting about the axis of cam shaft  1023 . In one embodiment, base  1032  is the transmission housing, which is secured to chassis  300 . The cam shaft is pivoted by means of a force applied to yoke  1021 , which is secured to one of the ends of cam shaft  1023 . 
   As the cam shaft is pivoted, one side of the flat surface  1027  will compressively press against the cam receiving surface of post  1016 . This will, in turn, displace the inboard caliper  1010  and the friction material  1008  on it toward the disk  1006 . 
   The brake calipers  1004  and  1010  can further include a plurality of fastening points  1024 ,  1026  and  1028  and  1030  at which the respective caliper is secured directly or indirectly to the chassis  300  of a model vehicle. As can be seen in  FIGS. 25A-D , for example, the fastening points  1024  and  1026  for the outboard caliper  1004  are where the caliper is attached to the base  1032  by means of screws through screw holes  1051  and  1053 . In the case of the inboard caliper  1010 , the caliper has securing holes  1028  and  1020  at each of its ends, which can slide over the shafts  1038  and  1040  of securing screws  1034  and  1036 . However, the caliper  1020  is not fixedly secured to the shaft portion of the screws, but instead is axially free to slide along the shafts of the screws so that the friction material disposed on the caliper can be pressed against the disk  1006  during brake actuation. 
   As indicated above, the disk  1006  is free to slide axially to some degree along the axis of drive shaft  1012 . Thus, as the inboard caliper  1010  and its friction material  1008  are forced toward the disk  1006 , the disk will be free to slide towards the friction material  1002  on the outboard caliper  1004 , which is fixed in place by means of the heads of the screws  1034  and  1026  securing it to base  1032 . Thus, when the brake is actuated by the cam, the axially slidable disk  1006  will be “sandwiched” in between the movable inboard caliper  1010  and the fixed outboard caliper  1004 , effectively applying braking force to stop rotation of the disk. This will stop rotation of the drive shaft  1012  which will also cause stopping of the rotation of all the wheels (not shown) connected to the drive shaft. 
   As can be seen in  FIGS. 25  A through D,  26 A and B,  27  and  FIG. 28 , one or more ribs  1042  and  1007  extend outwardly across substantially the entire length of the outer surface of the caliper  1004 . The term “inner”, when referring to either caliper  1004 ,  1010 , means the surface in contact with the friction material. “Outer” means the other surface of the caliper plate  1004 ,  1010 . Ribs  1007  extend substantially parallel to the circumference of an axle of shaft  1012  to be braked, while ribs  1042  extend substantially tangentially to the circumference of the axle or shaft  1012 . The ribs  1042  act to stiffen the caliper  1004  to distribute compressive forces applied to the outside face at one or more locations on the caliper, as well as to provide cooling. As can be seen best in  FIG. 25C , one or more of the ribs  1042  can be tapered in height as the rib approaches one of the plurality of plate fastening points  1034 ,  1036 . Thus, the ribs  1042  are the highest at the middle of the span, where the bending moment would be the highest. Furthermore, the one or more ribs  1042  extend across at least a portion of the outer faces of the calipers in substantial alignment with an imaginary line drawn through the center point of each of the plurality of fastening points  1034  and  1036 . The plurality of ribs  1007  extend across at least a portion of the outer surface of the calipers  1004  and  1010 , which can facilitate cooling of the calipers, as well as providing stiffening reinforcement. The ribs  1007  can each extend from the nearest rib  1042  on the outer surface of caliper  1004  to curve circumferentially about the axis of drive shaft  1012  toward an edge of caliper  1004 , thus providing additional stiffness in the direction of applied frictional force, in addition to providing cooling. 
   In order to retain the friction material  1002  and  1008  in position on the respective calipers, the calipers can include one or more brake pad bosses  1048  extending from the inner face of the caliper for engaging at least a portion of the perimeter of a pad of friction material  1002  or  1008  supported on the inner face of the caliper, to resist lateral movement of a brake pad  1002  or  1008  across the inner surface of the respective caliper. The bosses  1048  have space between them so that an operator can visually determine the degree of wear of friction material without the need for disassembly. The brake pad bosses  1048  can be sufficient alone to retain the friction material in position on the caliper without the need for reliance on other means for fastening the friction material to the caliper. However, if desired, the friction material can also be secured to the caliper by adhesive, screws, rivets or other convenient means 
   Co-pending U.S. patent application of Brent W. Byers entitled “A Model Vehicle Suspension Control Link” (Docket No. TRAX 3175000), filed concurrently herewith, is hereby incorporated by reference for all purposes. Components depicted in this application having substantially similar construction and function to those shown in the co-pending application hereby incorporated by reference are identified with the same reference numeral, followed by a prime (′) designation (e.g.,  100 ′). For example, various components employed in the construction and operation of the rear suspension arm assembly  100  in the co-pending application are substantially similar in construction and operation to the components employed in the front suspension arm assembly  100 ′ shown in  FIGS. 29A  through D. 
   Referring now to  FIGS. 29A  through D, shown is a front bulkhead assembly  658 , from which laterally extends a suspension arm assembly  100 ′ and a telescoping drive shaft  1100 . The telescoping drive shaft  1100  extends and retracts with upward and downward movement of the suspension arm assembly  100 ′. The drive shaft  1100  is secured by a Cardan joint  1102  (sometimes referred to as a “universal joint”) to a transmission differential assembly shown in  FIGS. 29A-D  mounted in a fixed position on the front bulkhead assembly  658 . The outboard end of the drive shaft  1100  is secured by a Cardan joint  1102  to an axle assembly  1104  (shown in one or more of  FIGS. 33D ,  34  and  35 ) mounted for rotation within an axle carrier  140 ′. The axle carrier  140 ′ is supported on the outboard end of the suspension arm assembly  100 ′. Extension and retraction of the telescoping drive shaft  1100  accommodates a different pivotal path followed by the axle carrier  140 ′ as the suspension arm assembly  100 ′ moves between uppermost and lowermost positions. 
   Referring now to  FIGS. 30A  through D,  31 A and B, and  32 A and B, the telescoping drive shaft  1100  is shown in greater detail. The drive shaft  1100  comprises an inboard yoke  1106  for securing a tubular external segment  1108  to the front transmission differential of the vehicle. An outboard yoke  1110  forms the outboard end of the drive shaft  1100  for securing a tubular internal segment  1112  to the Cardan joint  1102  coupling of the drive shaft  1100  to the axle assembly  1104 . The inboard and outboard yokes  1106 ,  1110  are integrally formed with the remainder of the external and internal segments  1108 ,  1112 , respectively, in a single-piece construction. 
   As is best shown in  FIGS. 32A and 32B , curved splines  1114 ,  1116  extend from the internal and external surfaces, respectively, of the external segment  1108  and the internal segment  1112  of the drive shaft  1100 . The splines  1114 ,  1116  extend at least along the lengths of the external and internal segments  1108 ,  1112  that will overlap when the suspension arm assembly  100 ′ travels between the uppermost and lowermost positions. The splines  1114 ,  1116  are aligned with the longitudinal axis of the shaft segments  1108 ,  1112 , respectively, in a parallel formation. In the embodiment shown, the splines  1114  extend along substantially the entire length of the inner wall of the external segment  1108 . The curved surfaces of the splines  1114 ,  1116  are complementary, each mating with a corresponding groove formed between adjacent splines of the external and internal segments  1108 ,  1112 , respectively. The splines  1114 ,  1116  vary in radius of curvature at approximately 180° intervals about the rotational axis of the drive shaft  1100 . In the embodiment shown, for example, indexing splines  1118  of the external segment  1108  and indexing splines  1120  of the internal segment  1112  have a smaller radius of curvature relative to other of the splines  1114 ,  1116 . The radius of curvature of the corresponding grooves with which the indexing splines  1118 ,  1120  mate, have a similarly smaller radius of curvature. This indexes the external and internal segments  1108 ,  1112  when mated, to assure alignment of the yokes  1106 ,  1110  in substantially the same rotational position. 
   The curved splines  1114 ,  1116  transfer torque between the yokes  1106 ,  1110 , while allowing the segments  1108 ,  1112  of the drive shaft  1100  to slide with respect to each other, in telescopic fashion. The curved surfaces of the splines  1114 ,  1116  allow more splines to be formed than if rectangular splines were used. The curved surfaces and number of the splines  1114 ,  1116  and corresponding grooves reduce or eliminate stress concentrations experienced by telescopic drive shafts employing rectangular splines. Stress reduction and accommodation of a greater number of splines  1114 ,  1116  is provided by a relatively larger than typical diameter employed by the drive shaft  1100 . These attributes also allow the walls of the internal and external segments  1108 ,  1112  to be thinner and lighter in weight. 
   The segments  1108 ,  1112  of the drive shaft  1100  are preferably manufactured from a low-friction, high impact strength plastic, or other similar material. In the embodiment shown, the segments  1108 ,  1112  are made from a suitable Nylon material. The low-friction attributes of these materials substantially eliminates the need to lubricate the surfaces of the segments  1108 ,  1112 . 
   The drive shaft  1100  is sealed to prevent dust, dirt, debris and the like from entering and causing abrasion of and friction between the surfaces of the segments  1108 ,  1112 , which would reduce performance and longevity. The ends of the drive shaft  1100  next to the yokes  1106 ,  1110  each include respective apertures  1122 ,  1124  that are sealed by elastomeric plugs  1126 ,  1128  secured by a compression fit. The seam between the surfaces of the external and internal segments  1108 ,  1112  is sealed by a bellows seal  1130 . 
   The bellows seal  1130  includes a substantially cylindrical central portion  1132 , having laterally extending folds, allowing both expansion and retraction of the bellows seal  1130  with expansion and contraction of the drive shaft  1100 . Extending from the inboard and outboard ends, respectively, of the bellows seal  1130  are substantially cylindrical, smooth sealing collars  1134 ,  1136 . The sealing collars  1134 ,  1136 , respectively, fit snugly over substantially cylindrical, smooth landing surfaces  1138 ,  1140  formed on the external surfaces of the segments  1108 ,  1112 . A seal is formed between the sealing collars  1134 ,  1136  and the landing surfaces  1138 ,  1140 , by a compression seal. In addition, the sealing collars  1134 ,  1136  are secured to the landing surfaces  1138 ,  1140 , by a suitable glue or adhesive. The bellows seal  1130  is preferably made from a suitable rubber compound, such as nitrile rubber, and the like. 
     FIGS. 33A  through D,  34  and  35  illustrate coupling of the drive shaft  1100  via the Cardan joint  1102  to a drive axle assembly  1104  for driving a wheel  120 ′ on the front end of the vehicle. The Cardan joint  1102  comprises the outboard yoke  1110  of the drive shaft  1100  coupled to a drive axle yoke  1142 . The drive axle assembly  1104  is supported by the axle carrier assembly  140 ′ for rotation. A drive pin  1144  couples the drive axle yoke  1142  to the drive axle assembly  1104  to transfer torque from the drive shaft  1100  to the wheel  120 ′. The drive axle yoke  1142  is supported for rotation within the axle carrier  140 ′ by an internally mounted radial ball bearing assembly  1146 . Supporting the drive axle assembly  1104  for rotation is a ball bearing assembly  1148  mounted in the axle carrier  140 ′ adjacent the wheel  120 ′. 
   In addition to transferring torque from the yoke  1142  to the axle assembly  1104 , the drive pin  1144  secures the yoke  1142  to the axle assembly  1104 . The drive pin  1144  comprises a substantially smooth, cylindrical pin extending through an aperture extending diametrically through the outboard shank of the drive axle yoke  1142  and an aligned aperture extending diametrically through a portion of the axle assembly  1104  inserted into the shank. The interior surfaces of the apertures of the shank of the drive axle yoke  1142  and the axle assembly  1104  are preferably smooth and provide sufficient clearance to allow the drive pin  1144  to be inserted and removed without difficulty. 
   The ball bearing assembly  1146  serves the dual purpose of supporting the drive axle yoke  1142  shank for rotation and securing the drive pin  1144  within the shank. This configuration allows replacement of the drive axle yoke  1142 , for example, if damaged, without the need to replace the drive axle assembly  1104  as well. Various manufacturing steps and associated costs are also reduced or eliminated 
     FIG. 36  illustrates substantially identical ball joint assemblies  1150  pivotally supporting the axle carrier  140 ′ on the outboard ends of the upper and lower suspension arms  102 ′,  104 ′. In  FIGS. 36 and 37 , the yoke  1142 , axle assembly  1104  and related components have been removed. The ball joint assemblies  1150  allow universal movement of the axle carrier  140 ′ relative to the suspension arms  102 ′,  104 ′ to allow steering, wheel alignment and suspension travel. 
   The ball joint assemblies  1150  each include a substantially spherical ball  1152  having a threaded shank  1154  securing each of the balls  1152  to one of the suspension arms  102 ′,  104 ′. Formed into each of the balls  1152  is a socket  1156 , preferably hexagonal, substantially aligned with the central axis of the threaded shank  1154 . The socket is used to secure the shanks  1154  to the suspension arms  102 ′,  104 ′ and to adjust the distance between the balls  1152  and the suspension arms  102 ′, 104 ′. Adjustment of the balls  1152 , in turn, allows adjustment of the camber of a wheel supported by the suspension arms  102 ′,  104 ′, in particular. Removal of the balls  1152  from their respective suspension arms  102 ′,  104 ′ facilitates maintenance and replacement of parts. 
   An inboard portion of each of the balls  1152  slides into a correspondingly shaped inboard end of a ball housing  1158 . Each ball housing  1158  is generally cylindrical and extends from the outboard surface of the axle carrier  140 ′, beginning with a diameter large enough to accommodate insertion of the ball  1152  and forming a substantially a spherical surface ending in an inboard aperture through which the ball shank  1154  extends. Formed in the surfaces of each housing  1158  are threads  1160  for receiving and securing a pivot ball cap  1162  for retaining each ball  1152  within the respective housing  1158 . 
   Each pivot ball cap  1162  is generally tubular, having external threads  1164  mating with housing threads  1160  and an inboard bearing surface  1166  for securing a ball  1152  within the respective housing  1158 . The bearing surface  1166  is formed about the open, inboard end of each cap  1162  and is substantially flush with the spherical surface of the associated ball  1152 . The pivot ball caps  1162  are tightened to just take up excess clearance with the balls  1152 , the threads have a mild interference fit with the housing threads  1160  to prevent loosening of the caps  1162 . Removal of the caps  1162  allows the balls  1152  to be removed from the housings  1158  for maintenance, repair and replacement. Extending from the perimeter of the outboard end of each of the caps  1162  are a number of fingers  1167 , forming a castle gear that is used to thread and unthread each of the caps  1162 . It will be apparent that the number of fingers  1167  and their configuration may be varied, as desired. 
   Seated in each cap  1162  is a self-healing cap seal  1168  to prevent dust, debris, dirt and other contaminants from entering the housings  1158 . Each cap seal  1168  includes a head portion  1170  having a radial lip extending to the fingers  1167  of the cap  1162 . The head portions  1170  rest on and form a seal against the throat portions  1172  of the caps  1162  extending inwardly and inboard of the fingers  1167 , forming a landing for the head portions  1170 . Extending from the head portion  1170  of each cap seal  1168  is a neck  1174  extending through and contacting the surfaces of the cap throat portion  1172 , forming a further seal. Each cap seal  1168  includes a retaining lip  1176  extending radially from the neck  1174  to assist in retaining the seal within the respective cap  1162 . The cap seals  1168  are preferably manufactured from a pliable nitrile rubber that can be deformed, but will elastically return to the original shape. 
   Formed in the head portion  1170  of each cap seal  1168  is a self-healing aperture  1178 . The self-healing aperture  1178  is preferably formed by a pair of slits cut through the head portion  1170  intersecting at substantially 90°. The slits normally abut to maintain a seal. However, a hexagonal wrench, lubricating nozzle or other tool can be inserted through the self-healing aperture  1178 , parting the lips of the slits, to adjust, remove, maintain or lubricate the associated ball  1152 . When the tool is removed, the self-healing aperture  1178  elastically returns to the original, sealed position. 
   The inboard end of each housing  1158  is sealed by an elastic boot  1180  that extends between the shank  1154  of each ball  1152  and a landing  1182  formed on the axle carrier  140 ′ about the inboard aperture of the ball joint housing  1158 . Each boot  1180  is generally conical in shape, extending from a wider opening adjacent the axle carrier  140 ′, to a smaller opening that surrounds the associated shank  1154 . Each boot is preferably manufactured from a material similar to that of the cap seals  1168 . The walls of each boot preferably form a number of folds, allowing the boot  1180  to flex easily with movement of the axle carrier  140 ′, and without tearing or binding. 
   Referring now to  FIGS. 37 ,  38  and  39  A through C, each boot  1180  is secured to the landing  1182  by a ring  1184  which fits over and compresses a cylindrical portion of the boot  1180  into sealing engagement with the landing  1182 . A lip  1186  extends radially from the cylindrical portion of the boot  1180  and is compressed against a shoulder  1188  formed on the surface of the axle carrier  140 ′. Each ring  1184  is held in this position by a pair of clips  1190  extending substantially perpendicularly from and on diametrically opposed points on the ring. The clips  1190  are pressed over a pair of clip receptacles  1192  positioned on opposite sides of the associated ball housing  1158 . The rings  1184  and clips  1190  are preferably manufactured from a strong, impact-resistant plastic. 
   The inboard ends of the boots  1180  are each secured to the associated shanks  1150  by an elastic collar  1194  integrally formed at the narrower opening of each of the boots  1180 . The elastic collars  1194  are substantially thicker than the walls of their respective boots  1180  and form a compression seal against the underlying surface of the associated shank  1154 . Each collar  1194  is retained by an annular insert  1196  formed about the circumference of the associated shank  1154  at a location preferably outboard of the respective suspension arms  102 ′,  104 ′. The shoulders of the annular inserts  1196  retain the collars  1194  from sliding over the associated shanks  1154   
   Turning now to  FIGS. 40A-D ,  41 A-B and  42 , a dual arm centrally mounted steering arm  1200  driven by a pair of servos  1202  is depicted. The centrally mounted steering arm  1200  is pivotally mounted to a mounting bracket  1204  by means of a mounting screw  1206 , which passes through a bushing  1208 , a center hole  1207  in a retainer  1209 , and a center hole  1210  in steering arm  1200 . 
   At each of the ends  1211  of steering arm  1200  are yokes  1212 , to which can be attached a rod assembly  1214 . Each rod assembly  1214  includes two ball joint ends  1216  and a center rod portion  1218 . In one embodiment, the ball joint ends  1216  employ hollow ball bushings  1220 . One of the ball joint ends  1216  is pivotally connected to one of the yokes  1212  by means of screw  1222 , which passes through the yoke  1212  and through the hole in the hollow ball bushing  1220 . The other of the ball joint ends  1216  is pivotally connected to an actuator arm  1217  of one of the pair of servos  1202  by means of screw  1219  through yoke  1225  at the end of actuator arm  1217 . Actuator arm  1217  is, in turn, attached to the output shaft  1224  of the servo by means of attachment screw  1226 . 
   In operation, when the operator desires to turn the vehicle, a signal is sent to both of the servos  1202  at substantially the same time. Each of the servos  1202  will cause their output shafts  1224  to pivot in opposite directions, at about the same time. This will cause rod assembly  1214  to extend and retract, applying force to the yokes  1212  of the steering arm, respectively, pivoting the centrally mounted steering arm  1200 . 
   In order to minimize the potential for damage to the servos or their connecting rods and arms, a spring and cam servo saver  1240  assembly is used to connect to a driven steering arm  1242 . Driven steering arm  1242  is, in turn, connected to a pair of hollow ball end steering control tie rods  1244 , one of which controls the steering position of one of the two front wheels  120 ′, and the other of which controls the steering position of the other of the two front wheels. The ball end of each of the tie rods  1244  is attached to an end  1246  of driven steering arm  1242  by means of screws  1248 . Driven steering arm  1242  pivots about bushing  1208 , which passes through a hole  1250  in driven steering arm  1242 . 
   The servo saver assembly includes retainer  1209 , spring  1252 , centrally mounted steering arm  1200  and driven steering arm  1242 . Centrally mounted steering arm  1200  includes a pair of axially rotable arcuate lugs  1254 , which act as cam surfaces, which fit into cooperatively designed hollows  1256  in the facing surface of driven steering arm  1242 , which act as mating cam surfaces. Retainer  1209  is then secured to driven steering arm  1242  by means of screws  1258 , with conical spring  1252  resiliently urging centrally mounted steering arm  1200  against driven steering arm  1242  so that lugs  1254  center themselves into hollows  1256 . 
   Under normal steering, the resilient force of spring  1252  is sufficient to keep lugs  1254  in place in hollows  1256  so that pivoting of centrally mounted steering arm  1200  by driving it with servos  1202  will cause driven steering arm  1242  to simultaneously pivot, ultimately resulting in steering of the wheels through steering control links  1244 . However, when the vehicle wheel strikes an obstruction during rough driving for example, excessive forces can be imposed on the steering components that might cause damage to the components. When this occurs, the driven steering arm  1242  will pivot relative to centrally mounted steering arm  1200 , causing lugs  1254  to rise out of the hollows  1256  against the resilient force of spring  1252 . This relative pivoting limits transmission of force from driven steering arm  1242  to the rest of the steering components, thus minimizing the potential for damage. However, immediately upon removal of the excessive force, the lugs  1254  will “pop” back into hollows  1256  under the resilient force of spring  1252 , thus returning the steering assembly to normal operation. 
   By use of a pair of servos  1202  mounted on the left and right side of the chassis  300 , a symmetrical torque is applied to the steering arm  1200 . This results in a huge benefit to performance minded users due to crisp break away, strong centering and less looseness and/or hysteresis in the system. Furthermore, use of a centrally mounted steering arm permits use of a single, central servo saver, instead of a separate servo saver for each servo, eliminating additional parts and looseness and/or hysteresis in the system 
   Turning now to  FIGS. 43A-D  and  44 - 46 , a mounting system for securely mounting a servo  1202  to the chassis  300  by means of a clamp style bracket  1300  and a clamp style bracket  1301  is depicted. Servo  1202  includes a housing  1302 , which can conveniently be molded of plastic. Housing  1302  includes attachment ears  1304  extending from the ends thereof, which can conveniently be molded integrally with the ends of housing  1302 . 
   Rather than attach the attachment ears  1304  directly to the chassis  300  by means of screws, for example, as is conventional, in accordance with the present invention, a clamp style forward bracket  1300  and a clamp style aft bracket  1301  are employed to secure the attachment ears to the chassis  300 . Forward bracket  1300  has an upper flange  1306  and a lower flange  1308 . Upper flange  1306  has a pair of threaded holes  1309  which are adapted to receive the threaded end of a screw  1311 . Upper flange  1306  and lower flange  1308  are connected at one end by an arcuate live hinge  1310 , which can conveniently be molded integrally with upper flange  1306  and lower flange  1308  from plastic material. In addition, lower flange  1308  can includes one or more downwardly extending boss portions  1329 A and  1329 B, which extend below the upper surface of chassis  300 , into the openings  1307 A and  1307 B of the chassis, to fix the forward bracket  1300  against forward/aft movement. Lower flange  1308  has a hole  1313  disposed through it for accepting the shaft  1315  of screw  1311 . Hole  1313  need not be threaded. 
   Aft bracket  1301  has an upper flange  1316  and a lower flange  1318 . Upper flange  1316  has a pair of threaded holes  1319  which are adapted to receive the threaded end of a screw  1311 . Upper flange  1316  threaded and lower flange  1318  are connected at each of their sides by an arcuate live hinge  1320 , which can conveniently be molded integrally with upper flange  1316  and lower flange  1318  from plastic material. Lower flange  1318  can have one or more downwardly extending lateral bosses  1330  and  1331 , which extend below the upper surface of chassis  300 , into respective openings  1333  and  1335  of the chassis, to fix the aft bracket  1300  against forward/aft movement. Lower flange  1318  has a hole  1323  disposed through it for accepting the shaft  1325  of screw  1311 . Hole  1323  need not be threaded. 
   To secure the body  1302  of servo  1202 , forward bracket  1300  is put onto the end of one of the attachment ears  1304 , and bracket  1301  is put onto the end of the other of the attachment ears  1304 . Then, screws  1311  are secured, securely clamping one of the ears  1304  between upper flange  1306  and lower flange  1308 , and the other of the ears between upper flange  1316  and lower flange  1318 . 
   Brackets  1300  and  1301  can be manufactured from Zytel 70 G 33 (33% Glass) available from DuPont, which retains shape and grips screw threads better than plastics without a glass reinforcing fill. 
   By use of the clamping type brackets of an embodiment of the present invention, a wide range of aftermarket dimensions of servos can be accommodated without requiring additional parts and without compromise in the mounting integrity. Furthermore, the clamp style interface distributes loads over the entire mounting ear thereby reducing breakage/distortion of the mounting ears, overall improvement in durability. In addition, the clamp style mounting type brackets also improve control performance by increasing the stiffness of the servo-vehicle interface. Of course, the forward and aft brackets could be reversed, if desired 
     FIGS. 47A  and B illustrate a vehicle  1400  incorporating the various features described herein, including in Appendices A, B, C and D hereto, which are incorporated herein by reference. 
   Referring now also to  FIGS. 1 and 47A  through  52 , illustrated is a chassis  300 , which is also described elsewhere in connection with other features and components comprising portions of the vehicle  1400 . The chassis  300  is configured to provide a lower center of gravity than can typically be provided by conventional chasses resembling a relatively flat surface or plate. This is accomplished by providing chassis  300  with flanges  302  extending laterally from a central channel area  304 . The lateral flanges  302  extend from downwardly sloping lateral walls  306  of the central channel area  304  at a substantially lower level relative to an underlying surface. The lateral flanges  302  provide support for relatively heavy components that do not require placement near or in alignment with the drive train of the vehicle  1400 . In general, the flanges  302  lower the mounting points of various components on the chassis  300 , at least relative to the transmission assembly  520  and transmission output shaft  521 . In addition, the flanges  302  preferably incline gradually as they extend laterally from the channel area  304 . Upward sloping of the flanges  302  causes the components supported on the flanges  302  to extend both upwardly and inwardly toward the center of the vehicle  1400 , more tightly packaging the components on the chassis  300 . 
   The flanges  302  preferably include openings  308 , for example, through which the lower portions of components can extend, in addition to being secured to the flanges  302  at a lower level than the central channel area  304 . Where convenient, chassis  300  weight is reduced by configuring one or more flanges  302  as a support arm, such as arms  302 A, that cooperates with other flanges  302  to support components on the chassis  300 . Further, the flanges  302  may preferably extend laterally and substantially without upward inclination, if desired to enhance performance of the component or to satisfy structural or packaging preferences. 
   The flanges  302  are capable of supporting numerous components of the vehicle  1400  at a level substantially lower than the central channel area  304 . In the embodiment shown, the flanges  302  support at a lower level, an electronics and battery package  1402 , a fuel tank, the engine assembly  500 , a servo and battery package  1404  and steering servos  1202 . Of these components, the flanges  302  tilt inwardly the engine assembly  500  and the steering servos  1202 . 
   An advantage of the configuration of the chassis  300  is the ability to mount the engine assembly  500  lower with respect to the transmission assembly  520 . Preferably, the transmission assembly  520  is centrally mounted on the central channel area  304 , while the engine assembly  500  is mounted to the chassis  300  at a lower point on one or more of the flanges  302 . The chassis  300  is configured in this manner to preferably position the drive shaft  501  of the engine assembly  500  within the range of about 3 mm to 13 mm vertically above (of relative to the ground) the level of the transmission output shaft  521 . The chassis  300  is preferably press-formed and cut from a sheet of anodized aluminum. It will be apparent that the flanges  302  and a central channel area  304  may be configured in other the variations and configurations to achieve a lower center of gravity overall for the vehicle  1400 . 
   In addition to providing a lower center of gravity for the vehicle  1400 , the chassis  300  includes forward and rearward extension plates  310 ,  312  positioned at substantially the same vertical level as the central channel area  304 . The forward and rearward extension plates  310 ,  312  are preferably formed integrally with the upper surface of the central channel area  304  and support various components of the front suspension, steering and rear suspension assemblies of a vehicle  1400  at a higher vertical level than if those assemblies were secured to the flanges  302 . Thus, the chassis  300  maintains desirable ground clearance beneath the suspension and drive assemblies, while providing a relatively low center of gravity. 
   In steering systems, for optimum performance, it is important to maintain geometric parameters within certain desired ranges. Some of these well-known parameters are toe-in, camber, caster and roll center. Toe-in is the angle that the wheels make with respect to a line through the centerline the vehicle, when viewed from above. 
   Camber is the inclination of the wheel, from vertical, as viewed from the front of the vehicle. It is usually designed to vary with wheel travel in order to help keep the tire squarely on the ground. As described elsewhere in this application, camber is adjustable on the vehicle. 
   Caster is defined as the inclination, from vertical, of the wheel&#39;s steering axis as viewed from the side of the vehicle. That is, generally speaking, caster is a tilt of the steering axis toward the front or back of the vehicle. Basically viewing from the side of the vehicle, draw a line through the upper and lower ball joint of the axle carrier. The angle off of vertical is the caster. The caster angle is adjusted by moving the mounting point of the upper arm (effectively the upper ball joint) generally fore and aft with the spacers on the hinge pin of the upper arm. Adjusting caster changes the steering characteristics of the vehicle. 
   Roll center is adjusted by moving the inner mounting point of the upper arm up and down. This changes the front view Instant Center (IC) of the suspension. The IC partially defines the roll center. 
   “Bump steer” can be defined as undesirable steering (toeing in or toeing out) of the wheel/tire during travel (vertical) of the suspensions, assuming that the steering wheel or actuation mechanism is being held fixed. Bump steer occurs because the toe change is caused by geometric differences in the motion arc of the steering control link (toe control link) and the suspension arms during bump travel of the suspension. Basically, if the vehicle is going straight and then hits a bump with a wheel, the raising of the wheel due to the bump changes the toe, causing the vehicle to tend to veer off without any movement of the steering wheel/steering actuator. Bump steer tends to be more sensitive to caster and roll center changes than other parameters. 
   Bump steer is usually impossible to eliminate due to packaging and design limitations. Generally, a compromise setting is made to optimally minimize at the standard suspensions settings. However, having a way to adjust bump steer is desirable due to the range of caster and roll center adjustments available in the suspension. 
   It is known to attempt to minimize bump steer by varying the vertical position of the mounting points (front view) of the steering control link on the axle carrier  140 ′ of the front wheels. Thus, minimizing bump steer while adjusting caster and roll center is difficult and complicated, requiring extensive trial and error on the part of the operator. For example, once an adjustment to caster and/or roll center is made, bump steer is reintroduced by the new settings unless there is a provision for “tuning” it back out. 
   An embodiment of the present invention incorporates an adjustment feature that allows the bump steer to be optimized (minimized) for a substantially complete set of possible combinations of suspension settings; i.e., from 5 degrees to 15 degrees of caster, in 2.5 degree increments and for either an “upper” or “lower” roll center position. Referring to  FIGS. 53 ,  54 A-E and  55 , this is accomplished by providing the attachment pin of the axle carrier  140 ′, to which the pivot link  154  at the end of the control link is attached, with clearance for permitting movement of the pivot link  154  up and down on the attachment pin  1390 . Ring-shaped spacers A, B or C, taken from a predetermined set of spacers having predetermined thickness are disposed on the pin  1390  above and/or below the pivot link  154  to take up the clearance and position the pivot link  154  at the optimum position on the pin. The predetermined thicknesses for the spacers A, B and C are predetermined for each combination of caster and roll center adjustments by geometric calculations and spacers having the appropriate thicknesses are in a kit, along with a table indicating which spacers to use and where to position them on the pin. 
   Referring to  FIGS. 53 ,  54 A-E and  55 , and initially to  FIG. 53  thereof, a perspective view of the suspension assembly  1380  for the left front wheel is depicted. Suspension assembly  1380  includes upper and lower suspension arms  1382  and  1384 , to which is attached an axle carrier  140 ′. Axle carrier  140 ′ has an arm  1386  having generally vertical pin  1390  thereon. Control link  110 , which extends from a driven steering arm  1242  (not shown) includes a pivot link  154  pivotably attached to pin  1390 . 
     FIGS. 54A-E  show detailed views of the axle carrier  140 ′, pin  1390  and pivot link  154  with various predetermined combinations of ring-shaped spacers A-B positioned on the pin, above and/or below the pivot link  154 . It should be noted that, to replace the spacers, pin  1390  is first removed, the spacers and pivot link  154  (or  154 ″″) placed onto it, and then the pin is replaced. 
   In  FIG. 53A , a thick spacer of thickness A is disposed above pivot link  154  and a thin spacer of thickness B is disposed below the pivot link  154 . As shown in  FIG. 55 , this combination is used where there is a 5 degree caster and the roll center setting is at the “lower” setting. This combination is also used where there is a 7.5 degree caster and the roll center setting is at the “lower” setting. 
   In  FIG. 54B , a thick spacer of thickness A is disposed above pivot link  154  and a thin spacer of thickness B is also disposed above the pivot link  154 . As shown in  FIG. 55 , this combination is used where there is a 5 degree caster and the roll center setting is at the “upper” setting. 
   In  FIG. 54C , a thick spacer of thickness A is disposed below pivot link  154  and a thin spacer of thickness B is also disposed below the pivot link  154 . As shown in  FIG. 55 , this combination is used where there is a 10 degree caster and the roll center setting is at the “lower” setting. This combination is also used where there is a 12.5 degree caster and the roll center setting is at the “upper” setting. 
   In  FIG. 54D , a thick spacer of thickness A is disposed below pivot link  154  and a thin spacer of thickness B is disposed above the pivot link  154 . As shown in  FIG. 55 , this combination is used where there is a 10 degree caster and the roll center setting is at the “lower” setting. This combination is also used where there is a 12.5 degree caster and the roll center setting is at the “upper” setting. 
   In  FIG. 54E , a “standard” configuration can be employed, where a standard hollow ball pivot link  154 ″″ is used that has approximately equal length collars  155  and  157  at its upper and lower sides that form part of the pivot link  154 ″″. Alternatively, spacers can be used that have the same, medium thickness “C,” thus, positioning the pivot link at the approximate midpoint of pin  1390 . Such a medium positioning is listed in the table of  FIG. 55  as “tall center hollow ball.” This centered combination is used where there is a 7.5 degree caster and the roll center setting is at the “lower” setting. This combination is also used where there is a 10 degree caster and the roll center setting is at the “upper” setting. 
   Of course, because the caster angles and roll center settings will vary by vehicle geometry, weight and other parameters, the above caster angles and roll center settings are only examples for a particular vehicle of a particular geometry, weight and other parameters. Of course, finer increments (such as 1 degree increments for caster and more increments for the roll center setting) could be employed, resulting in more spacer thicknesses and combinations thereof. 
     FIGS. 56 ,  57 A through D and  58 A through D, illustrate one configuration of a front suspension assembly  1500  secured to a front bulkhead assembly  1502  of the vehicle  1400 . The suspension assembly  1500  comprises upper and lower suspension arms  1504  and  1506  pivotally mounted to the bulkhead assembly  1502 . A rocker arm  1508  is pivotally mounted to a post or boss  1510  extending at an angle into the bulkhead assembly  1502 , inboard and above the point of connection of the upper suspension arm  1504  to the bulkhead assembly  1502 . The rocker arm  1508  is pivotally coupled to a push rod  1512  and a damper assembly  1514 . The outboard end of the push rod  1512  is pivotally secured to the outboard end of the lower suspension arm  1506 , urging the suspension arm  1506  outwardly and downwardly. Upward movement of the suspension arm  1506  displaces the push rod  1512  inwardly toward the rocker arm  1508 , which in turn pivots to compress the damper  1514  against a pivot pin  1516 . Downward movement of the suspension arm  1506  displaces the push rod  1512  outwardly, which in turn pivots the rocker arm  1508  to release the damper  1514 . The rocker arm  1508  is generally triangular in shape. The portion of the rocker arm  1508  pivotally connected to the push rod  1512  is referred to as the input arm. A portion of the rocker arm  1508  pivotally connected to the damper assembly  1514  is referred to as the output arm. 
   The damper  1514  is generally aligned with the longitudinal axis of the vehicle  1400  and a substantially horizontal position, with a slight upward inclination from the point of connection to the bulkhead assembly  1502  toward the point of pivotal connection to the rocker arm  1508 . The substantially horizontal position of the damper  1514 , mounted adjacent the points of connection of the suspension arms  1504 ,  1506  to the bulkhead assembly  1502 , reduces vertical space requirements and protects the damper  1514  from damage. 
   The rocker arm  1508  pivots about an axis substantially perpendicular to the axis of the push rod  1512  at some point during operation of the suspension assembly  1500 . The rocker arm  1508  pivotal axis is oriented to translate movement of the damper assembly  1514  into substantial alignment with the push rod  1512  as the rocker arm  1508  pivots. The push rod  1512  is mounted to the rocker arm  1508  for pivotal movement along vertical and horizontal axes relative to the rocker arm  1508 . As the suspension assembly  1500  moves, the push rod  1512  pivots upwardly and downwardly relative to its point of connection to the rocker arm  1508 , following vertical movement of the outboard end of the suspension arm  1506 . 
   Referring now to  FIGS. 57A  through D, the suspension assembly  1500  is shown in the full bump position, with the suspension arms  1504 ,  1506  displaced to their uppermost extent. This position corresponds with the vehicle  1400  reaching a lowermost position relative to an underlying surface. In this position, the push rod  1512  rotates the rocker arm  1508  toward a damper  1514 , substantially fully compressing the damper  1514 . 
   Referring now to  FIGS. 58A  through D, the suspension assembly  1500  and is shown in the full droop position, with the suspension arms  1504 ,  1506  extended to their lowermost extent. This position corresponds with the vehicle  1400  reaching its highest position relative to an underlying surface. In this position, the damper  1514  rotates the rocker arm  1508  to fully extend the push rod  1512 . 
   A position intermediate to the full bump and full droop positions is the ride height position. In the ride height position, the suspension assembly  1500  reaches an equilibrium position in which the force exerted by the push rod  1512  counteracts the vehicle weight placed on the suspension arms  1504 ,  1506 . In general, relative proportions of total travel distance of the outboard ends of the suspension arms  1504 ,  1506  at the axle carrier  140 ′ (i) from ride height to full bump and (ii) from the ride height to full droop is referred to as the up/down travel distribution. The travel distribution of the suspension assembly  1500  is approximately two-thirds to one third. A ride height of the vehicle  1400  can be adjusted by changing the point of connection of the outboard end of the push rod  1512  to the outboard and of the suspension arm  1506 . This is accomplished by movement of the push rod  1512  outboard end between a number of positioning apertures  1518  to which the push rod is secured by a pin  1520 . 
   The suspension assembly configuration of  FIGS. 56 through 64  provides numerous advantages. Amongst many advantages too numerous to list, but that will nevertheless be apparent to those skilled in the art, the configuration of the suspension assembly  1500  is capable of providing relatively large motion ratios (MR), a relatively large range of travel between full bump and full droop positions, enhanced progressiveness of the suspension, as well as the ability to relatively accurately adjust the suspension progressiveness over the range of movement. The motion ratio (MR) is generally described as the ratio of vertical displacement of the wheel to displacement of a corresponding suspension spring member. Depending on the suspension design, motion ratios often vary over the range of suspension travel. Accordingly, it is often useful to define the motion ratio at various points in the suspension travel. The motion ratio at a particular point in the travel range is referred to as the instantaneous motion ratio. A progressive suspension is generally one in which the suspension spring force at the wheel increases non-linearly as the suspension spring member is displaced by vertical wheel travel. Progressiveness can be defined as a change in motion ratio (MR) of the suspension over some range of travel. 
   Furthermore, a variety of performance characteristics can be independently adjusted in the assembly  1500 , without substantially affecting other performance characteristics. For example, the ride height of the assembly  1500  can be adjusted without significantly affecting the travel distribution or the wheel rate. This is because adjustment of the ride height has a relatively insignificant effect on a motion ratio of the suspension assembly  1500 . 
   For example, progression of the suspension assembly  1500  is primarily affected by the angle between the input and output arms of the rocker arm  1508 , along with the starting angle between the damper  1514  and the output arm, as shown by angle A in  FIG. 64 . The progression rate can be relatively easily varied accurately by substitution of rocker arms having appropriate dimensions. 
   As described in pages 42 through 43 of the REVO Owners Manual, appended hereto as Appendix A and incorporated herein by reference for all purposes, and on pages 42-43 thereof, the progression rate (or progressiveness) of the suspension determines the extent to which the spring force produced at the wheel by one or more suspension spring members being displaced will vary with suspension travel, or vertical travel of the wheel. A suspension configuration functions progressively when the spring force at the wheel (or suspension force) increases with movement toward the full bump position, at a progressively increasing, non-linear rate. The non-linearly increasing suspension force of a progressively functioning suspension can be achieved using one or more associated suspension spring members that become progressively stiffer (i.e., the spring rate increases, as does the perceived stiffness of the spring member) with displacement. By comparison, a suspension configuration functions linearly or at constant-rate when the spring force at the wheel (or suspension force) increases with movement toward the full bump position, at a substantially steadily increasing, linear rate. This linearly increasing suspension force can be achieved using one or more associated suspension spring members that do not become substantially stiffer with displacement and an associated suspension assembly linkage that substantially does not function progressively. 
   It will be apparent to those skilled in the art, that a suspension can be configured to function progressively through one or more segments of wheel travel or throughout the entire range of wheel travel. Moreover, the degree of progressiveness can be varied as desired with wheel travel. The configuration of the suspension and/or variation in the stiffness of the one or more associated spring members can be employed to produce the degree of progressiveness associated with suspension wheel travel desired. 
     FIGS. 62A  and B and  63 A and B illustrate, respectively, rear suspension assembly and front suspension assembly rocker arms. Variation of the dimensions A, B, C, D and E, as well as the lengths of associated pushrods will vary the progressiveness of the suspension assemblies. Dimensions associated with a variety of progressiveness and suspension travel are listed in Table 1. The dimension values listed in Table 1, except for dimension C (in degrees), can be for millimeters in an embodiment, or for centimeters in another embodiment, or for other units of measure in yet other embodiments, depending upon the desired scale or size of the vehicle. Further, the values presented illustrate the relative proportions of the various components of corresponding embodiments; however, it will be apparent to those skilled in the art that other dimension values can be substituted, if desired and that the suspension disclosed is not limited to the dimension values provided. 
     FIGS. 59 through 61  identify dimensions of the left front and rear suspension assemblies having motion ratios of approximately 4.5 to 1 and high-performance progressiveness curves. The numerical values of the dimensions identified in  FIGS. 59 through 61  are shown in Tables 2 through 5 below. The dimensions listed in Tables 2 through 5 can be for millimeters in an embodiment, or for centimeters in another embodiment, or for other units of measure in yet other embodiments, depending upon the desired scale or size of the vehicle. Further, the values presented illustrate the relative proportions of the various components of corresponding embodiments; however, it will be apparent to those skilled in the art that other dimension values can be substituted, if desired, and that the suspension disclosed is not limited to the dimension values provided. Variations of these dimensions will yield various motion ratios and progressiveness curves in the suspension assembly  1500 . 
   
     
       
         
             
           
             
               TABLE 1 
             
           
          
             
                 
             
             
               Dimensions of Front and Rear Suspension Assembly Rocker Arms 
             
          
         
         
             
             
             
             
             
             
             
             
          
             
                 
                 
               Pushrod 
                 
                 
                 
                 
                 
             
             
               End 
               Rocker 
               Length 
               A 
               B 
               C 
               D 
               E 
             
             
                 
             
             
               Front 
               Progressive 1 
               115.55 
               38.20 
               20.00 
               98.00 
               8.10 
               16.20 
             
             
                 
               Progressive 2 
               120.50 
               38.40 
               20.00 
               88.65 
               8.10 
               16.20 
             
             
                 
               Progressive 3 
               125.25 
               39.45 
               20.00 
               80.50 
               8.10 
               16.20 
             
             
                 
               Long travel 
               115.55 
               40.00 
               15.20 
               92.50 
               8.10 
               16.20 
             
             
               Rear 
               Progressive 1 
               115.55 
               30.60 
               19.00 
               85.00 
               3.60 
               16.70 
             
             
                 
               Progressive 2 
               120.50 
               30.90 
               19.00 
               72.80 
               3.60 
               16.70 
             
             
                 
               Progressive 3 
               125.25 
               32.00 
               19.00 
               63.00 
               3.60 
               16.70 
             
             
                 
               Long travel 
               115.55 
               43.40 
               19.00 
               81.00 
               3.60 
               16.70 
             
             
                 
             
          
         
       
     
   
   Referring now to  FIG. 59 , values of the dimensions x 1 -x 9  and y 1 -y 8  appear in the first part of Tables 2 through 5 below. Table 2 lists the values of various dimensions of the suspension utilizing P 1  (Progressive  1 ) rocker arms. Table 3 lists the values of various dimensions of the suspension utilizing P 2  (Progressive  2 ) rocker arms. Table 4 lists the values of various dimensions of the suspension utilizing P 3  (Progressive  3 ) rocker arms. Table 5 lists the values of various dimensions of the suspension utilizing LT (Long Travel) rocker arms. 
   Referring now to  FIG. 60 , values of dimensions x 1 -x 9  and dimensions y 1 -y 8  appear in the second part of Tables 2 through 5 below. Table 2 lists the values of various dimensions of the suspension utilizing P 1  (Progressive  1 ) rocker arms. Table 3 lists the values of various dimensions of the suspension utilizing P 2  (Progressive  2 ) rocker arms. Table 4 lists the values of various dimensions of the suspension utilizing P 3  (Progressive  3 ) rocker arms. Table 5 lists the values of various dimensions of the suspension utilizing LT (Long Travel) rocker arms. 
   Referring now to  FIG. 61 , values of dimensions x 1 -x 2  and z 1 -z 10  appear in the third part of Tables 2 through 5 below. Table 2 lists the values of various dimensions of the suspension utilizing P 1  (Progressive  1 ) rocker arms. Table 3 lists the values of various dimensions of the suspension utilizing P 2  (Progressive  2 ) rocker arms. Table 4 lists the values of dimensions of the suspension utilizing P 3  (Progressive  3 ) rocker arms. Table 5 lists the values of various dimensions of the suspension utilizing LT (Long Travel) rocker arms. 
   
     
       
         
             
           
             
               TABLE 2 
             
           
          
             
                 
             
             
               Suspension Dimensions with P1 Rocker Arms 
             
          
         
         
             
             
             
             
             
             
          
             
               Name 
               Value 
               What 
               Name 
               Value 
               What 
             
             
                 
             
          
         
         
             
          
             
               Front suspension, view from front, P1 rocker arms 
             
          
         
         
             
             
             
             
             
             
          
             
               x1 
               5.5 
               LCA pivot 
               y1 
               52.3 
               Lower ball 
             
             
                 
                 
                 
                 
                 
               joint/pivot ball 
             
             
               x2 
               12.5 
               Damper on rocker 
               y2 
               58.0 
               Pushrod on LCA 
             
             
               x3 
               26.5 
               UCA pivot 
               y3 
               73.0 
               LCA pivot 
             
             
               x4 
               29.5 
               Rocker pivot 
               y4 
               113.3 
               UCA pivot 
             
             
               x5 
               39.9 
               Pushrod on rocker 
               y5 
               127.8 
               Pushrod on rocker 
             
             
               x6 
               131.8 
               Pushrod on LCA 
               y6 
               127.0 
               Rocker pivot 
             
             
               x7 
               154.0 
               Lower ball joint/pivot 
               y7 
               137.3 
               Damper on rocker 
             
             
                 
                 
               ball 
             
             
               x8 
               165.5 
               Center of tire contact 
               y8 
               97.3 
               Upper ball joint 
             
             
                 
                 
               patch 
             
             
               x9 
               153.3 
               Upper ball joint 
             
          
         
         
             
          
             
               Rear suspension, view from rear, P1 rocker arms 
             
          
         
         
             
             
             
             
             
             
          
             
               x1 
               5.5 
               LCA pivot 
               y1 
               52.0 
               Lower ball 
             
             
                 
                 
                 
                 
                 
               joint/pivot ball 
             
             
               x2 
               11.8 
               Damper on rocker 
               y2 
               50.8 
               Pushrod on LCA 
             
             
               x3 
               27.1 
               UCA pivot 
               y3 
               73.1 
               LCA pivot 
             
             
               x4 
               30.5 
               Rocker pivot 
               y4 
               106.8 
               UCA pivot 
             
             
               x5 
               33.9 
               Pushrod on rocker 
               y5 
               118.1 
               Pushrod on rocker 
             
             
               x6 
               127.8 
               Pushrod on LCA 
               y6 
               123.5 
               Rocker pivot 
             
             
               x7 
               155.3 
               Lower ball joint/pivot 
               y7 
               122.8 
               Damper on rocker 
             
             
                 
                 
               ball 
             
             
               x8 
               166.2 
               Center of tire contact 
               y8 
               97.7 
               Upper ball joint 
             
             
                 
                 
               patch 
             
             
               x9 
               154.5 
               Upper ball joint 
             
          
         
         
             
          
             
               Top view, P1 rocker arms 
             
          
         
         
             
             
             
             
             
             
          
             
               x1 
               16.5 
               Front Damper Mount 
               z1 
               90.0 
               Front Damper Mount 
             
             
               x2 
               11.8 
               Rear Damper Mount 
               z2 
               23.2 
               Pushrod on Front 
             
             
                 
                 
                 
                 
                 
               Rocker 
             
             
                 
                 
                 
               z3 
               16.4 
               Front Pushrod on LCA 
             
             
                 
                 
                 
               z4 
               11.9 
               Front Damper on 
             
             
                 
                 
                 
                 
                 
               rocker 
             
             
                 
                 
                 
               z5 
               13.6 
               Front Rocker pivot 
             
             
                 
                 
                 
               z6 
               88.5 
               Rear Damper Mount 
             
             
                 
                 
                 
               z7 
               16.2 
               Pushrod on Rear 
             
             
                 
                 
                 
                 
                 
               Rocker 
             
             
                 
                 
                 
               z8 
               14.7 
               Rear Pushrod on LCA 
             
             
                 
                 
                 
               z9 
               14.2 
               Rear Rocker pivot 
             
             
                 
                 
                 
               z10 
               8.6 
               Rear Damper on rocker 
             
             
                 
             
             
               LCA Lower control arm 
             
             
               UCA Upper control arm 
             
          
         
       
     
   
   
     
       
         
             
           
             
               TABLE 3 
             
           
          
             
                 
             
             
               Suspension Dimensions with P2 Rocker Arms 
             
          
         
         
             
             
             
             
             
             
          
             
               Name 
               Value 
               What 
               Name 
               Value 
               What 
             
             
                 
             
          
         
         
             
          
             
               Front suspension, view from front, P2 rocker arms 
             
          
         
         
             
             
             
             
             
             
          
             
               x1 
               5.5 
               LCA pivot 
               y1 
               52.3 
               Lower ball 
             
             
                 
                 
                 
                 
                 
               joint/pivot ball 
             
             
               x2 
               12.6 
               Damper on rocker 
               y2 
               58.0 
               Pushrod on LCA 
             
             
               x3 
               26.5 
               UCA pivot 
               y3 
               73.0 
               LCA pivot 
             
             
               x4 
               29.5 
               Rocker pivot 
               y4 
               113.3 
               UCA pivot 
             
             
               x5 
               35.7 
               Pushrod on rocker 
               y5 
               130.4 
               Pushrod on rocker 
             
             
               x6 
               131.8 
               Pushrod on LCA 
               y6 
               127.0 
               Rocker pivot 
             
             
               x7 
               154.0 
               Lower ball joint/pivot 
               y7 
               137.3 
               Damper on rocker 
             
             
                 
                 
               ball 
             
             
               x8 
               165.5 
               Center of tire contact 
               y8 
               97.3 
               Upper ball joint 
             
             
                 
                 
               patch 
             
             
               x9 
               153.3 
               Upper ball joint 
             
          
         
         
             
          
             
               Rear suspension, view from rear, P2 rocker arms 
             
          
         
         
             
             
             
             
             
             
          
             
               x1 
               5.5 
               LCA pivot 
               y1 
               52.0 
               Lower ball 
             
             
                 
                 
                 
                 
                 
               joint/pivot ball 
             
             
               x2 
               12.8 
               Damper on rocker 
               y2 
               50.8 
               Pushrod on LCA 
             
             
               x3 
               27.1 
               UCA pivot 
               y3 
               73.1 
               LCA pivot 
             
             
               x4 
               30.5 
               Rocker pivot 
               y4 
               106.8 
               UCA pivot 
             
             
               x5 
               29.7 
               Pushrod on rocker 
               y5 
               120.7 
               Pushrod on rocker 
             
             
               x6 
               127.8 
               Pushrod on LCA 
               y6 
               123.5 
               Rocker pivot 
             
             
               x7 
               155.3 
               Lower ball joint/pivot 
               y7 
               129.1 
               Damper on rocker 
             
             
                 
                 
               ball 
             
             
               x8 
               166.2 
               Center of tire contact 
               y8 
               97.7 
               Upper ball joint 
             
             
                 
                 
               patch 
             
             
               x9 
               154.5 
               Upper ball joint 
             
          
         
         
             
          
             
               Top view, P2 rocker arms 
             
          
         
         
             
             
             
             
             
             
          
             
               x1 
               16.5 
               Front Damper Mount 
               z1 
               90.0 
               Front Damper Mount 
             
             
               x2 
               11.8 
               Rear Damper Mount 
               z2 
               24.1 
               Pushrod on Front 
             
             
                 
                 
                 
                 
                 
               Rocker 
             
             
                 
                 
                 
               z3 
               16.4 
               Front Pushrod on LCA 
             
             
                 
                 
                 
               z4 
               10.9 
               Front Damper on 
             
             
                 
                 
                 
                 
                 
               rocker 
             
             
                 
                 
                 
               z5 
               11.3 
               Front Rocker pivot 
             
             
                 
                 
                 
               z6 
               88.5 
               Rear Damper Mount 
             
             
                 
                 
                 
               z7 
               17.0 
               Pushrod on Rear 
             
             
                 
                 
                 
                 
                 
               Rocker 
             
             
                 
                 
                 
               z8 
               14.7 
               Rear Pushrod on LCA 
             
             
                 
                 
                 
               z9 
               14.2 
               Rear Rocker pivot 
             
             
                 
                 
                 
               z10 
               7.7 
               Rear Damper on rocker 
             
             
                 
             
             
               LCA Lower control arm 
             
             
               UCA Upper control arm 
             
          
         
       
     
   
   
     
       
         
             
           
             
               TABLE 4 
             
           
          
             
                 
             
             
               Suspension Dimensions with P3 Rocker Arms 
             
          
         
         
             
             
             
             
             
             
          
             
               Name 
               Value 
               What 
               Name 
               Value 
               What 
             
             
                 
             
          
         
         
             
          
             
               Front suspension, view from front, P3 rocker arms 
             
          
         
         
             
             
             
             
             
             
          
             
               x1 
               5.5 
               LCA pivot 
               y1 
               52.3 
               Lower ball 
             
             
                 
                 
                 
                 
                 
               joint/pivot ball 
             
             
               x2 
               12.7 
               Damper on rocker 
               y2 
               58.0 
               Pushrod on LCA 
             
             
               x3 
               26.5 
               UCA pivot 
               y3 
               73.0 
               LCA pivot 
             
             
               x4 
               29.5 
               Rocker pivot 
               y4 
               113.3 
               UCA pivot 
             
             
               x5 
               31.8 
               Pushrod on rocker 
               y5 
               133.0 
               Pushrod on rocker 
             
             
               x6 
               131.8 
               Pushrod on LCA 
               y6 
               127.0 
               Rocker pivot 
             
             
               x7 
               154.0 
               Lower ball joint/pivot 
               y7 
               137.4 
               Damper on rocker 
             
             
                 
                 
               ball 
             
             
               x8 
               165.5 
               Center of tire contact 
               y8 
               97.3 
               Upper ball joint 
             
             
                 
                 
               patch 
             
             
               x9 
               153.3 
               Upper ball joint 
             
          
         
         
             
          
             
               Rear suspension, view from rear, P3 rocker arms 
             
          
         
         
             
             
             
             
             
             
          
             
               x1 
               5.5 
               LCA pivot 
               y1 
               52.0 
               Lower ball 
             
             
                 
                 
                 
                 
                 
               joint/pivot ball 
             
             
               x2 
               12.9 
               Damper on rocker 
               y2 
               50.8 
               Pushrod on LCA 
             
             
               x3 
               27.1 
               UCA pivot 
               y3 
               73.1 
               LCA pivot 
             
             
               x4 
               30.5 
               Rocker pivot 
               y4 
               106.8 
               UCA pivot 
             
             
               x5 
               25.7 
               Pushrod on rocker 
               y5 
               123.3 
               Pushrod on rocker 
             
             
               x6 
               127.8 
               Pushrod on LCA 
               y6 
               123.5 
               Rocker pivot 
             
             
               x7 
               155.3 
               Lower ball joint/pivot 
               y7 
               129.0 
               Damper on rocker 
             
             
                 
                 
               ball 
             
             
               x8 
               166.2 
               Center of tire contact 
               y8 
               97.7 
               Upper ball joint 
             
             
                 
                 
               patch 
             
             
               x9 
               154.5 
               Upper ball joint 
             
          
         
         
             
          
             
               Top view, P3 rocker arms 
             
          
         
         
             
             
             
             
             
             
          
             
               x1 
               16.5 
               Front Damper Mount 
               z1 
               90.0 
               Front Damper Mount 
             
             
               x2 
               11.8 
               Rear Damper Mount 
               z2 
               25.3 
               Pushrod on Front 
             
             
                 
                 
                 
                 
                 
               Rocker 
             
             
                 
                 
                 
               z3 
               16.4 
               Front Pushrod on LCA 
             
             
                 
                 
                 
               z4 
               10.9 
               Front Damper on 
             
             
                 
                 
                 
                 
                 
               rocker 
             
             
                 
                 
                 
               z5 
               13.6 
               Front Rocker pivot 
             
             
                 
                 
                 
               z6 
               88.5 
               Rear Damper Mount 
             
             
                 
                 
                 
               z7 
               17.9 
               Pushrod on Rear 
             
             
                 
                 
                 
                 
                 
               Rocker 
             
             
                 
                 
                 
               z8 
               14.7 
               Rear Pushrod on LCA 
             
             
                 
                 
                 
               z9 
               14.2 
               Rear Rocker pivot 
             
             
                 
                 
                 
               z10 
               7.3 
               Rear Damper on rocker 
             
             
                 
             
             
               LCA Lower control arm 
             
             
               UCA Upper control arm 
             
          
         
       
     
   
   
     
       
         
             
           
             
               TABLE 5 
             
           
          
             
                 
             
             
               Suspension Dimensions with LT Rocker Arms 
             
          
         
         
             
             
             
             
             
             
          
             
               Name 
               Value 
               What 
               Name 
               Value 
               What 
             
             
                 
             
          
         
         
             
          
             
               Front suspension, view from front, LT rocker arms 
             
          
         
         
             
             
             
             
             
             
          
             
               x1 
               5.5 
               LCA pivot 
               y1 
               52.3 
               Lower ball 
             
             
                 
                 
                 
                 
                 
               joint/pivot ball 
             
             
               x2 
               16.8 
               Damper on rocker 
               y2 
               58.0 
               Pushrod on LCA 
             
             
               x3 
               26.5 
               UCA pivot 
               y3 
               73.0 
               LCA pivot 
             
             
               x4 
               29.5 
               Rocker pivot 
               y4 
               113.3 
               UCA pivot 
             
             
               x5 
               40.2 
               Pushrod on rocker 
               y5 
               128.0 
               Pushrod on rocker 
             
             
               x6 
               131.8 
               Pushrod on LCA 
               y6 
               127.0 
               Rocker pivot 
             
             
               x7 
               154.0 
               Lower ball joint/pivot 
               y7 
               134.9 
               Damper on rocker 
             
             
                 
                 
               ball 
             
             
               x8 
               165.5 
               Center of tire contact 
               y8 
               97.3 
               Upper ball joint 
             
             
                 
                 
               patch 
             
             
               x9 
               153.3 
               Upper ball joint 
             
          
         
         
             
          
             
               Rear suspension, view from rear, LT rocker arms 
             
          
         
         
             
             
             
             
             
             
          
             
               x1 
               5.5 
               LCA pivot 
               y1 
               52.0 
               Lower ball 
             
             
                 
                 
                 
                 
                 
               joint/pivot ball 
             
             
               x2 
               12.7 
               Damper on rocker 
               y2 
               50.8 
               Pushrod on LCA 
             
             
               x3 
               27.1 
               UCA pivot 
               y3 
               73.1 
               LCA pivot 
             
             
               x4 
               30.5 
               Rocker pivot 
               y4 
               106.8 
               UCA pivot 
             
             
               x5 
               35.2 
               Pushrod on rocker 
               y5 
               118.4 
               Pushrod on rocker 
             
             
               x6 
               127.8 
               Pushrod on LCA 
               y6 
               123.5 
               Rocker pivot 
             
             
               x7 
               155.3 
               Lower ball joint/pivot 
               y7 
               129.1 
               Damper on rocker 
             
             
                 
                 
               ball 
             
             
               x8 
               166.2 
               Center of tire contact 
               y8 
               97.7 
               Upper ball joint 
             
             
                 
                 
               patch 
             
             
               x9 
               154.5 
               Upper ball joint 
             
          
         
         
             
          
             
               Top view, LT rocker arms 
             
          
         
         
             
             
             
             
             
             
          
             
               x1 
               16.5 
               Front Damper Mount 
               z1 
               90.0 
               Front Damper Mount 
             
             
               x2 
               11.8 
               Rear Damper Mount 
               z2 
               25.0 
               Pushrod on Front 
             
             
                 
                 
                 
                 
                 
               Rocker 
             
             
                 
                 
                 
               z3 
               16.4 
               Front Pushrod on LCA 
             
             
                 
                 
                 
               z4 
               10.9 
               Front Damper on 
             
             
                 
                 
                 
                 
                 
               rocker 
             
             
                 
                 
                 
               z5 
               11.0 
               Front Rocker pivot 
             
             
                 
                 
                 
               z6 
               88.5 
               Rear Damper Mount 
             
             
                 
                 
                 
               z7 
               29.0 
               Pushrod on Rear 
             
             
                 
                 
                 
                 
                 
               Rocker 
             
             
                 
                 
                 
               z8 
               14.7 
               Rear Pushrod on LCA 
             
             
                 
                 
                 
               z9 
               14.2 
               Rear Rocker pivot 
             
             
                 
                 
                 
               z10 
               8.0 
               Rear Damper on rocker 
             
             
                 
             
             
               LCA Lower control arm 
             
             
               UCA Upper control arm 
             
          
         
       
     
   
   Progressiveness can be defined as the change in motion ratio of the suspension over some range of travel, as described in Appendix C, “Revo Suspension Claims.” Two or more different ranges of travel can be considered. Moreover, at each point along any range of travel there is an instantaneous motion ratio (MR). Over a first range of travel, from fully extended (full droop) to fully compressed (full bump), the change in motion ratio is ΔMR 1 . Over a second range of travel, from ride height to fully compressed (full bump), the change in motion ratio is ΔMR 2 . Additionally, there is an average motion ratio (MR ave ), which is the ratio of the full range of wheel travel to the full range of damper (including one or more spring members) travel. The average motion ratio (MR ave ) is the ratio of vertical displacement of the wheel over its full range of travel to displacement of one or more corresponding suspension spring members (or associated damper) over its entire range of travel. It will be apparent to those skilled in the art that a measure of progressiveness can then be defined as a ratio of ΔMRn/MR ave , or the ratio of one change in motion ratio over a particular range of travel (ΔMRn) to the average motion ratio over an entire range of travel (MR ave ), where “n” signifies a particular range of motion. For example, if ΔMR 2  has a value of 0.49 and MR ave  has a value of 4.5:1, then the measure of progressiveness ΔMR 2 =0.49/4.5=11%. 
   Having thus described the present invention by reference to certain of its preferred embodiments, it is noted that the embodiments disclosed are illustrative rather than limiting in nature and that a wide range of variations, modifications, changes, and substitutions are contemplated in the foregoing disclosure and, in some instances, some features of the present invention may be employed without a corresponding use of the other features. Many such variations and modifications may be considered obvious and desirable by those skilled in the art based upon a review of the foregoing description of preferred embodiments. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the invention.