Abstract:
A snow vehicle is disclosed comprising a vehicle frame, a propulsion unit coupled to the frame, and a front ski steered by a steering mechanism. The front of the vehicle includes a first front suspension and a second front suspension coupled to the ski. The rear suspension includes a bumper assembly preventing bottoming out of the rear suspension. The rear suspension is coupled to the vehicle frame such that the longitudinal spacing between the vehicle frame and rear suspension is adjustably controllable.

Description:
BACKGROUND 
       [0001]    The present disclosure relates to snow vehicles including snowmobiles and or snow bikes. 
         [0002]    Many types of vehicles are configured with tracks to drive in the snow. Regardless of whether the vehicle is a snowmobile or a wheeled vehicle converted to a tracked vehicle, tracked vehicles typically include a drive shaft mounted to a suspension system that supports the endless track. The drive shaft typically includes drive sprockets that engage the endless track. Irregularities in the snow and ice covered terrain cause the suspension system to move. Shock absorbers are typically used to absorb the movement of the suspension system. Common suspension systems are configured to collapse towards the tracked vehicle when absorbing the movement. However, in some situations, the irregularities in the terrain cause movement in the suspension away from the tracked vehicle that is not accommodated by the suspension system. 
         [0003]    In the case of snow bikes, the front suspension comprises the suspension of the motorbike or dirt bike, that is, a front shock absorber. In the case of snowmobiles, the front suspension is typically includes two control arms, also known as double A-arms. However the front snowmobile suspension can also be a trailing arm suspension. The suspension described herein would typically supplement any of the front suspensions discussed above, although it could also be the primary suspension. 
         [0004]    One such snow vehicle is shown in our U.S. Pat. No. 8,910,738, the subject matter of which is incorporated herein by reference. This patent discloses a conversion of a motorbike into a snow vehicle where the motorbike powertrain is utilized to power the track of the converted snow vehicle. 
       SUMMARY 
       [0005]    In a first embodiment, a snow vehicle comprises a vehicle frame; a propulsion unit coupled to the frame; at least one front ski; a steering mechanism coupled to the frame; a first front suspension coupled to the frame; a second front suspension coupled to the at least one ski; a rear suspension coupled to the frame, the rear suspension comprising: at least one slide rail; at least one control arm coupled between the slide rail and the frame; at least linear force element coupled between the slide rail and the frame; and at least one carrier roller coupled to the at least one slide rail and the frame; a bumper assembly preventing bottoming out of the rear suspension; and a drive system comprising a drive track slidably guided by the at least one slide rail and drivably coupled to the propulsion unit. 
         [0006]    In another embodiment, a snow vehicle comprises a vehicle frame; a propulsion unit coupled to the frame; at least one front ski; a steering mechanism coupled to the frame; a first front suspension coupled to the frame; a second front suspension coupled to the at least one ski; a rear suspension coupled to the frame, the rear suspension comprising: at least one slide rail; at least one control arm coupled between the slide rail and the frame; at least linear force element coupled between the slide rail and the frame; and at least one carrier roller coupled to the at least one slide rail and the frame; and a drive system comprising a drive track slidably guided by the at least one slide rail and drivably coupled to the propulsion unit; wherein the longitudinal spacing between the vehicle frame and rear suspension is adjustably controllable. 
         [0007]    In another embodiment, a kit for converting a motorcycle into a snow vehicle comprises at least one front ski; a front suspension for dampened coupling between a frame of the motorcycle and the at least one ski, the front suspension comprising a coupler for coupling the front suspension to the ski; a rear suspension for coupled to the frame of the motorcycle, the rear suspension comprising: at least one slide rail; at least one control arm coupled between the slide rail and the frame; at least linear force element coupled between the slide rail and the frame; and at least one carrier roller coupled to one of the slide rail and the frame; and a drive system comprising a drive track slidably guided by the at least one slide rail and drivably coupled to a propulsion unit of the motorcycle. 
         [0008]    In another embodiment, a rear suspension for a snow vehicle, comprises at least one slide rail; a frame; at least one control arm coupled between the slide rail and the frame; at least linear force element coupled between the slide rail and the frame; at least one carrier roller coupled to one of the slide rail and the frame; a drive system comprising a drive track slidably guided by the at least one slide rail and drivably coupled to the propulsion unit; and a bumper assembly coupled to the rear suspension and positioned to prevent contact of the at least control arm and a remaining portion of the rear suspension. 
         [0009]    In another embodiment, a rear suspension for a snow vehicle comprises at least one slide rail; a frame; at least one control arm coupled between the slide rail and the frame; at least linear force element coupled between the slide rail and the frame; at least one carrier roller coupled to one of the slide rail and the frame; a drive system comprising a drive track slidably guided by the at least one slide rail and drivably coupled to the propulsion unit; and a chain tensioner coupled to the frame at a forward end thereof, the chain tensioner comprising at least one first elongate portion, at least one second elongate portion, a mounting portion coupled to the at least one second elongate portion, and fasteners coupling the at least one first elongate portion and at least one second elongate portion together, wherein the at least one second elongate portion is movable relative to the at least one first elongate portion to vary a distance between the mounting portion and the remainder of the frame. 
         [0010]    In another embodiment, a snow vehicle comprises a vehicle frame; a foot peg positioned on the vehicle frame for a rider&#39;s foot; a propulsion unit coupled to the frame; at least one front ski; a steering mechanism coupled to the frame; a front suspension coupled to the frame; a rear suspension coupled to the vehicle frame, the rear suspension comprising: a suspension frame; at least one slide rail; at least one control arm coupled between the slide rail and the frame; at least linear force element coupled between the slide rail and the frame; and at least one carrier roller coupled to the at least one slide rail and the frame; a drive system comprising a drive track slidably guided by the at least one slide rail and drivably coupled at a drive axis (A 1 ) to the propulsion unit; wherein a vertical distance (Y 1 ) between a top of the foot peg to the drive axis (A 1 ) is less than 5″ (inches), and a vertical distance (Y 2 ) between the drive axis (A 1 ) and a bottom of the drive track is greater than 11″ (inches). 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    The invention will now be described in relation to the drawing figures where: 
           [0012]      FIG. 1  is a side view of one of the embodiments of snow vehicle as disclosed in the present disclosure; 
           [0013]      FIG. 2A  shows a left front perspective view of the front suspension coupled to the snow vehicle; 
           [0014]      FIG. 2B  is a front suspension similar to that of  FIG. 2A  showing the front suspension coupled to a conventional snowmobile; 
           [0015]      FIG. 3  is a front left perspective view of the suspension assembly; 
           [0016]      FIG. 4  is a rear right perspective view of the suspension assembly of  FIG. 3 ; 
           [0017]      FIG. 5  is a view similar to that of  FIG. 3  showing the suspension in an exploded manner; 
           [0018]      FIG. 5A  is an enlarged portion of the linkage assembly shown in  FIG. 5 ; 
           [0019]      FIG. 5B  is an enlarged portion of the shock absorber mounting as shown in 
           [0020]      FIG. 5 ; 
           [0021]      FIG. 6A  shows a side view of the front suspension coupled to a ski in the fully extended position; 
           [0022]      FIG. 6B  shows the front suspension of  FIG. 6 a    in a full trounce position; 
           [0023]      FIG. 7  shows a front left perspective view of the rear suspension shown in  FIG. 1 ; 
           [0024]      FIG. 8  shows a rear right perspective view of the rear suspension shown in  FIG. 7 ; 
           [0025]      FIG. 9  shows a left side plan view of the suspension shown in  FIG. 7 ; respectively; 
           [0026]      FIG. 10  shows a left side plan view of the suspension shown in  FIG. 7 ; 
           [0027]      FIG. 11  shows a front left perspective view of the rear suspension of  FIG. 7  in an exploded manner; 
           [0028]      FIG. 12  shows a front left perspective view of an upper frame portion of the rear suspension assembly; 
           [0029]      FIG. 13  shows a rear right perspective view of the upper frame portion shown in  FIG. 12 ; 
           [0030]      FIG. 14  shows a rear suspension coupler coupled to the slide rails; 
           [0031]      FIG. 15  shows an enlarged perspective view of the bumper assembly; 
           [0032]      FIG. 16  is an exploded view of the bumper assembly of  FIG. 15 ; 
           [0033]      FIG. 17  is a cross-sectional view of the bumper assembly shown through lines  17 - 17  of  FIG. 15 ; 
           [0034]      FIG. 18  shows a side view of the bumper assembly in full extension (dotted lines) and in full trounce (solid lines); 
           [0035]      FIG. 19  shows a front left perspective view of a second embodiment of the rear suspension; 
           [0036]      FIG. 20  shows an enlarged portion of the front of the suspension shown in  FIG. 19 ; 
           [0037]      FIG. 21  shows an enlarged view of the chain tensioner located at the front of the rear suspension assembly of  FIG. 19 ; 
           [0038]      FIG. 22  shows an exploded view of the chain tensioner shown in  FIG. 21 ; 
           [0039]      FIGS. 23 and 24  show opposite views of the chain tensioner bar; 
           [0040]      FIGS. 25A and 25B  show extreme positions of the chain tensioner in use; 
           [0041]      FIG. 26  shows a front perspective view of the bumper assembly of the rear suspension of  FIG. 19 ; 
           [0042]      FIG. 27  shows an enlarged view of the mounting of the bumper assembly to the rear control arm; 
           [0043]      FIG. 28  shows an exploded view of the bumper assembly of  FIG. 27 ; 
           [0044]      FIG. 29  shows an underside perspective view of the rear control arm; 
           [0045]      FIG. 30  shows a side view of the bumper assembly in contact with the slide rail in a trounce position (solid lines) and prior to contact (dotted lines); 
           [0046]      FIG. 31  shows a front perspective view of a third embodiment of rear suspension; 
           [0047]      FIG. 32  is an exploded view of the rear suspension of  FIG. 31 ; 
           [0048]      FIG. 33  shows an enlarged view of main frame portion of the third rear suspension; 
           [0049]      FIG. 34  shows a rear perspective view of the main frame portion of  FIG. 33 ; 
           [0050]      FIG. 35  shows a rear perspective view of the suspension assembly coupled to the rear control arm; 
           [0051]      FIG. 36  shows a front perspective view of the suspension assembly shown in  FIG. 35 ; 
           [0052]      FIG. 36A  shows an alternate embodiment of the rear suspension assembly of  FIG. 36 ; 
           [0053]      FIG. 37  shows a rear perspective view of the suspension assembly shown in  FIG. 36 ; 
           [0054]      FIG. 38  shows an exploded view of the suspension assembly shown in  FIGS. 36 and 37 ; 
           [0055]      FIG. 39  shows the suspension assembly of  FIGS. 37 and 38  when in an extended position; 
           [0056]      FIG. 40  shows the suspension assembly of  FIG. 39  when in the trounce position; 
           [0057]      FIG. 41  shows an enlarged front left perspective view of a front end of  FIG. 31 ; 
           [0058]      FIG. 42  shows a partially exploded view of  FIG. 41 ; and 
           [0059]      FIG. 43  shows an enlarged front right perspective view of a front end of  FIG. 31 . 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0060]    With reference first to  FIG. 1 , a snow vehicle is shown generally at  2  as comprised of a motorcycle portion  4  having a propulsion unit  5 , which is shown as a two-cylinder motorcycle engine, a frame  6 , an operators seat  8 , and a steering assembly  10  which includes a front fork  12 . A first suspension member is shown at  14  as a shock absorber assembly axially coupled with the forks  12 . A second front suspension assembly is shown at  16  which couples the steering assembly  10  directly to a ski  18 . A rear suspension assembly  20  is shown having an upper frame portion  22 , slide rails  24 , side panels  26 , control arms  28 ,  30 , linear force elements  32  and  34  (shown as shock absorbers) and an endless belt or drive track  36 . With reference still to  FIG. 1 , the snow vehicle  2  includes a foot peg  38  for the rider to position their foot thereon during a ride. 
         [0061]    With reference now to  FIGS. 2A and 3-5 , the front suspension assembly  16  will be described in greater detail. As shown best in  FIGS. 3 and 4 , front suspension assembly  16  generally includes a spindle body  40 , a lower linkage portion  42 , and a mounting portion  44 . As shown best in  FIG. 5 , spindle portion  40  is generally comprised of two plates  50  and  52  where each plate includes a plurality of apertures. Namely, plate  50  includes apertures  50   a - 50   g  together with an enlarged aperture at  50   h.  Likewise, plate  52  includes apertures  52   a - 52   g  and an enlarged aperture at  52   h.  Spindle portion  40  also includes a plurality of spacers to space the plates  50  and  52  apart, namely spacers  54   a,    54   b,    54   c,  and  54   g.  An enlarged spacer is provided at  54   h.  It should be noted each of the spacers  54   a,    54   b,    54   c,  and  54   g  are somewhat spool-shaped having an enlarged head portion  56  at each end as well as threaded openings  58  at each end. Enlarged spacer  54   h  is embossed at each end to define a reduced diameter section  60  defining shoulders  62 . 
         [0062]    Thus, the spindle portion may be preassembled by placing the reduced diameter portion  60  of spacer  54   h  into respective apertures  50   h  and  52   h.  This positions the reduced diameter portion  60  through the corresponding apertures  50   h  and  52   h  as shown in  FIGS. 3 and 4 . Spacers  54   c  and  54   g  may then be aligned with corresponding apertures  50   c,    52   c;  and  50   g,    52   g.  Fasteners and washers may then be positioned against plates  50  and  52  to retain the two plates together and coupled to the spacers. Namely, fastener  70   c  and washer  72   c  may be aligned with aperture  52   c  and brought into threaded engagement with threaded aperture  58  of spacer  54   c.  Likewise, fasteners  70   g  and washers  72   g  may be received through apertures  50   g  and  52   g  to be received into the threaded ends  58  of spacer  54   g.  The fasteners should be brought into engagement with the threaded apertures of their corresponding spacers but not fully torqued down at this position as other spacers and assembly is required within the spindle assembly. 
         [0063]    With reference still to  FIG. 5 , mounting portion  44  is shown including clamp halves  80 ,  82 ;  84 ,  86 . Each of the pairs of clamp halves includes semi-cylindrical openings which may encompass the front forks of the motorcycle frame as described above with reference to  FIG. 1 . Thus, spacers  54   a  and  54   b  are now aligned with respective pairs of apertures  50   a,    50   b;    52   a  and  52   b;  and fasteners  70   a  and  70   b  are received through their respective apertures as shown in  FIG. 5 . This brings fasteners into engagement with the threaded ends  58  of the corresponding spacers  54   a  and  54   b  to a position where the clamp may be closed. 
         [0064]    With reference now to  FIG. 5A , the link assembly  42  is shown and will be described in greater detail. As shown best in  FIG. 5A , link assembly  42  includes front links or control arms  100  and rear links or control arms  102 . Each control arm  100  includes an upper coupling  100   a  and a lower coupling at  100   b.  Likewise, control arms  102  include upper couplings at  102   a  and lower couplings at  102   b.  Each of the upper couplings  100   a  and  102   a  receive sleeves  104  which are profiled to be received in the couplings  100   a,    102   a.  Spacers  106  and  108  respectively, are then inserted through corresponding couplings  100   a,    102   a  and into sleeves  104 . Likewise, spacer  108  is received into couplings  102   a,  and into sleeves  104 . Thus, control arms  100  and  102  may be aligned with respective apertures  50   e,    52   e,  and  50   f,    52   f  ( FIG. 5 ) and fastened to the spindle assembly by way of fasteners and washers  70   e,    72   e  and  70   f,    72   f.    
         [0065]    With reference again to  FIG. 5A , linkage assembly  42  further includes a knuckle  110  having a front pivot coupling  110   a  having an aperture at  110   b  and a rear pivot coupling  110   c  having an aperture  110   d.  Sleeves  112  may be received in lower couplings  100   b  of control arms  100  (in the orientation shown in  FIG. 5A ) and then couplings  100   b  may be received in alignment with apertures  110   b  whereupon fasteners  114   a  and washers  114   b  may be aligned with threaded apertures  110   b  to couple control arms  100  with the knuckle  110 . In a like manner, sleeves  116  may be received in lower couplings  102   b  (in the orientation shown in  FIG. 5A ) whereby couplings  102   b  and sleeves  116  are received over rear pivot coupling  110   c  and in alignment with threaded apertures  110   d.  Thereafter, fasteners  120   a  and washers  120   b  may be aligned with sleeves  116  to couple alignment arms  102  with knuckle  110 . 
         [0066]    Finally, with reference to  FIG. 5B , linkage  42  further includes a shock absorber  124  having a lower coupling at aperture  124   a  and an upper coupling at aperture  124   b.  Split sleeves  126  include reduced diameter portions  126   a  and threaded apertures at  126   b.  Split sleeves  126  may be positioned with reduced diameter portions  126   a  in apertures  124   b  and the shock may be coupled to the spindle assembly by way of fasteners  70   d  and washers  70   e  positioned through apertures  50   d  ( FIG. 5 ) and into threaded engagement with threaded apertures  126   b.  The lower aperture  124   a  of shock  124  may then be coupled to bracket arms  102   c  as shown in  FIG. 5B . Sleeves  130  are positioned with reduced diameter portions  130   a  within the shock aperture  124   a.  The sleeves  130  and the shock aperture  124   a  are then aligned with apertures  102   d  whereupon fastener  140  may be received through sleeves  130 , apertures  102   d  and receive a fastener  142  and lock washer  144 . Thus, the entire assembled second suspension system  16  is shown in  FIGS. 3 and 4  where knuckle  110  is shown as providing an aperture  110   e  for coupling to ski  18  as shown above in  FIG. 2A . That is, ski  18  includes ski rails  18   a  whereby a pin  18   b  may be received through the rails and into aperture  110   e  for retaining ski  18  to the second suspension system  16 . Ski  18  could be similar to that shown in U.S. Pat. No. 8,381,857, the subject matter of which is incorporated herein by reference. 
         [0067]    Thus, in operation and with reference to  FIGS. 6A and 6B , ski  18  is shown in a fully extended position in  FIG. 6A  and in a full trounce position in  FIG. 6B . As shown in  FIG. 6B , control arms  100  and  102  are shown collapsed with the shock absorber  124  in a stroked position. Advantageously, the ski is lifted up and rearwardly relative to spindle assembly  40 . It is lifted upwardly in the sense that it rotated (in the clockwise sense as viewed in  FIG. 6B ). It is rotated in the range of 1-5°. It also moves rearwardly, for example, the position of the pin  18   b  which couples the ski to knuckle  110  moves rearwardly from the positions shown in  FIG. 6A  to the position shown in  FIG. 6B . That is, the distance in  FIG. 6A  between the upper pivot point of front control arm  100  (about fastener  70   e ) is shown as X 1 , whereas in  FIG. 6 b    the distance is shown as X 2 , where X 2  is greater than X 1 . This provides an enhanced suspension system in that the ski is lifted up and rearward; for example, if the snow bike is going over a rock or log, the ski is lifted up and over the log rather than pushing the ski into the log. This movement also reduces the friction between the ski and the snow due to the lifting of the ski. 
         [0068]    It should be understood that the spindle assembly may also be usable on a conventional snow mobile, and as shown in  FIG. 2B , spindle  16 ′ is shown coupled to upper and lower alignment arms or control arms  150 ,  152 , where upper control arm  150  is coupled to spindle assembly  16 ′ by way of a ball joint at  154 . Although not shown in  FIG. 2B , lower control arm  152  would also be coupled by way of a ball joint to spindle assembly  16 ′. It should be further understood that spindle assembly  16  or  16 ′ could be adapted for use with a trailing arm type snowmobile suspension of the type shown in U.S. Pat. No. 6,328,124, the subject matter of which is incorporated herein by reference. A full description of the front suspension is described in our co-pending patent application Ser. No. ______, filed Nov. 6, 2015 (Attorney Docket Number PLR-01-27450.02P), incorporated herein by reference. 
         [0069]    With reference now to  FIGS. 7-19 , rear suspension  20  will be described in greater detail. As shown, and in particular with reference to  FIGS. 9-11 , rear suspension  20  includes an upper portion  154 , an intermediate suspension portion  156  and a lower portion  158 . As shown, intermediate suspension portion  156  is coupled to the upper and lower portions  154 ,  158  in a four bar linkage fashion allowing the upper and lower portions  154 ,  158  to move relative to each other in dampened fashion. In addition to the items already described on rear suspension  20 , rear suspension  20  includes a drive system  160  which is input from the propulsion unit  6  by way of a chain; a belt drive system  162  driven by drive system  160  through gear casing or chain case  164  and a chain tensioner  166  ( FIG. 7 ) which is moveable into the drive chain for taking up slack. As shown best in  FIG. 8 , a disc brake  168  is shown on the backside of drive system  160  for braking the snow bike. Furthermore, a bumper system  170  is shown which as described herein, prevents a crash between upper and lower portions  154 ,  158  of the rear suspension  20 . 
         [0070]    With reference now to  FIGS. 12 and 13 , upper frame member  22  will be described in greater detail. As shown, upper frame  22  includes two longitudinal frame members  180  extending lengthwise the entire length of the frame member  22 . Frame member  180  is interrupted at a front end thereof by way of front cross bar  182  which couples to a front end portion  180   a  of frame member  180 . Frame portions  180   b  extend forwardly from cross-bar  182  and include front coupling members  184  which couple to a rear section of motorcycle portion  4  ( FIG. 1 ). Frame members  186  reinforce frame members  180   b  and cross tube  182  in a triangular manner, and while shown as frame tubes, gussets could also be used such as a triangular plate portion welded in place between frame members  180   b  and cross tube  182 . As shown best in  FIG. 13 , cross tube  190  couples together frame members  180 , where an end of cross tube  190  includes a threaded aperture at  190   a.  As shown best in  FIG. 12  a cross tube portion  192  is positioned above frame member  180  and includes a threaded aperture at  192   a.  As shown in both  FIGS. 12 and 13  a cross tube  196  is positioned rearwardly of cross tube  190  and also couples together frame members  180 . Cross tube  196  includes a threaded aperture at  196   a.  Finally, a cross tube  198  is positioned at a rear of frame member  22  and includes threaded apertures  198   a.  Brackets  200  are positioned intermediate cross tubes  182  and  190  to retain chain tensioner  166  and bracket  202  is attached to frame member  180  to attach drive member  160 . Upper frame members  210  extend from cross tube  182  rearwardly to cross tube  198  and include reinforcing frame members  212   a,    212   b,  and  212   c.    
         [0071]    Upper frame portion  154  ( FIGS. 9-11 ) further includes the side panels  26  and more particular left side panel  26   a  and right side panel  26   b  coupled to the upper frame member  22 . As shown best in  FIGS. 9 and 11 , side panel  26   a  is formed of a panel, such as an aluminum or stainless steel panel and is configured to couple to the left side of upper frame member  22 . In particular, panel  26  includes apertures to receive fasteners  222   a  which couples to threaded aperture  192   a  ( FIG. 12 ), fastener  222   b  to couple threaded fastener  196   a  ( FIG. 12 ) and fastener  222   c  to fasten to threaded aperture  198   a  ( FIG. 12 ). As shown in  FIG. 11 , left side panel  26   a  further includes apertures  230   a  and  230   b  for coupling to the intermediate suspension portion  156  as will be described herein. As shown in  FIG. 11 , side panel  26   a  further includes apertures  230   c  and  230   d  for receipt therethrough of a driveshaft for drive member  160  and an aperture for receipt of drive shaft for belt drive  162 . 
         [0072]    With reference now to  FIG. 10 , right hand side panel  26   b  includes apertures for receipt of fasteners  240   a  (for coupling with aperture  198   a ); fastener  240   b  (for coupling with threaded aperture  196   a ) and fastener  240   c  (for coupling with threaded aperture  198   a ). Side panel  26   b  also includes apertures for receipt of fasteners  242   a  and  242   b  which couple with intermediate suspension portion  156  as described herein. Side panel  26   b  also includes a mounting area  244  for coupling belt drive  162  ( FIG. 7 ). 
         [0073]    With reference again to  FIG. 11 , intermediate suspension  156  is comprised of a front control arm  250 , a front shock absorber at  252 , a rear control arm  254 , and a rear shock absorber at  256 . As shown, front control arm  250  has an upper axle at  260  and a lower axle at  262 . Upper axle  260  includes threaded apertures  260   a  and lower axle  262  includes threaded apertures  262   a.  Shock absorber  252  is coupled to upper axle  260  at  266  and includes a lower axle at  268  having a threaded aperture  268   a.  Rear control arm  254  includes an upper axle  270  having a threaded aperture at  270   a  and a lower axle  272  and mounted between slide rails  24 , as described herein. 
         [0074]    With reference now to  FIG. 14 , lower axle assembly  272  includes a spacer  274  having threaded apertures at  274   a  and axle  276  is slidably receivable over spacer  274  and sleeves  278  which are received in open ends  280  of axle member  276 . As shown, when spacer  274  is received through sleeves  278  and axle member  276 , fasteners  282   a  and  282   b  may be received through washers  284 , through apertures  286  of slide rails  24  such that axle member is rotatable about spacer  274 . It should be appreciated that the spacer  274  is slightly longer than the axle  276 , allowing the axle  276  to rotate about spacer  274 . Axle member  276  includes link arms  288  having apertures at  288   a  for coupling to rear control arm  254 . With reference again to  FIG. 11  rear control arm  254  includes threaded apertures  254   a  at a lower end thereof that may be coupled to apertures  288   a  ( FIG. 14 ) with fasteners (not shown). With respect still to  FIG. 11 , rear shock absorber  256  includes a lower axle  290  having a threaded aperture at  290   a.    
         [0075]    In addition to apertures  286  ( FIG. 14 ) slide rails  24  also include apertures  300 ,  302 , and  304  ( FIG. 11 ). Thus, and with reference to  FIG. 11 , intermediate suspension portion  156  may be coupled to slide rails  24  by way of fasteners through apertures  302  into threaded apertures  268 , by fasteners extending through apertures  304  into threaded apertures  262   a  and fasteners through apertures  300  and into threaded aperture  290   a.    
         [0076]    With reference now to  FIGS. 15-18 , bumper assembly  170  will be described in greater detail. As shown in  FIG. 15 , bumper assembly  170  is shown mounted to slide rail  24  above a slot  310  of slide rail  24 . Bumper assembly  170  generally includes a plunger at  312 , a spring grommet  314  and a carrier mount at  316 . With reference now to  FIG. 16 , the bumper assembly  170  is shown exploded away from slide rail  24 . As shown, plunger  312  includes a head portion  312   a,  a shank portion  312   b  and a threaded aperture at  312   c  (see  FIG. 17 ). Spring grommet  314  includes a pair of resilient bellows  314   a  and  314   b  coupled to a base portion  314   c  with an aperture  314   d  extending downwardly through spring grommet  314  and profiled to receive plunger  312 . Carrier mount  316  includes flanges  316   a  which flank a base portion  318  which includes an aperture  320  profiled to receive shank portion  312   b  of plunger  312  as described herein. 
         [0077]    To assemble the bumper assembly, plunger  312  is installed through aperture  314   d  of spring grommet  314  with base portion  314   c  positioned on base  318  of carrier mount  316 . If desired, a thrust washer could be positioned under the head portion  312   a  and above the spring grommet  314 . Fastener  322  may then be positioned through washer  324  and threadably received into threaded aperture  312   c  of plunger  312 . Fasteners  326  are then positioned through apertures  316   b  of flanges  316   a  to couple the bumper assembly to threaded apertures  328  on slide rail  24 . A cross-sectional view of  FIG. 17  shows the bumper assembly as applied to the side of slide rail  24 . As should be appreciated from  FIG. 17 , flanges  316   a  are offset asymmetrically with base  318  of mount  316  such that the plunger is centered with the slot  310 . Thus, as shown in  FIG. 18 , during a jounce, rear control arm  254  collapses and is aligned with bumper assembly  170 , and in particular with the head portion  312  of plunger  312 , causing spring grommet  314  to compress causing the shank portion  312   b  to extend into slot  310 . 
         [0078]    With reference now to  FIGS. 19-30 , a second embodiment of a rear suspension will be described. With reference to  FIG. 19  a second rear suspension is shown at  420  having a frame  422  with a single slide rail  424  where carrier rollers  425  flank single side rail  424 . Rear suspension  420  further includes side panels  426 , a front control arm  428 , rear control arm  430 , front shock absorber  432  and rear shock absorber  434 . As in the first embodiment, rear suspension  420  includes an input drive  460 , belt drive  462  coupled together by way of chain case  464 , a chain tensioner  466  and a braking system  468 . Rear suspension  420  further includes a rear bumper assembly  470  as described herein. With reference now to  FIGS. 20-25 , chain tensioner  466  will be described in greater detail. 
         [0079]    As shown first in  FIGS. 20 and 21 , frame  422  includes a front cross bar at  482  with elongate extension bars  488  coupled to cross bar  482  and extending generally forward. Sliding mounts  490  are coupled to elongate extension bars  488  and are slidable relative thereto. Chain tensioner  466  further includes a locking mechanism at  492  and a chain guide at  494 . 
         [0080]    As shown best in  FIG. 22 , elongate extension bars  488  include an inner end at  500  which is coupled to the cross bar  482 , an inner surface  502  which is substantially flat, and an outer surface at  504  having triangulated edges at  506 . Each of the bars  488  includes apertures at  510 . As shown in  FIGS. 23 and 24 , sliding mounts  490  are shown, where in  FIG. 23  an inner surface  514  is shown having an integrated channel at  516 . The channel  516  includes upper and lower surfaces  516   a,  an inner flat surface at  516   b,  and triangulated surfaces  516   c,  which as should be appreciated, align with and cooperate with triangulated surfaces  506  on bars  488 . Apertures  520  extend through inner surface  516   b  and are slotted in a longitudinal direction. 
         [0081]    As shown in  FIG. 24 , sliding mounts  490  include an outside flattened surface at  522 . A front end  524  of the sliding mount  490  includes a coupler at  526  which is substantially similar to coupler  184  ( FIG. 12 ) to couple the rear suspension  420  to the motorcycle frame. However, in this embodiment, the chain is tightened by providing longitudinal flexibility in the position of the rear suspension relative to the motorcycle frame. In that regard, fasteners  528  ( FIG. 22 ) are provided which are receivable through slotted apertures  520  and into threaded engagement with threaded apertures  510 . The triangulated surfaces  506 ,  516   c  allows vertical alignment of the sliding mounts relative to the bars  488  and positioning fasteners  528  into threaded engagement with threaded apertures  510  allows sliding mounts  490  to be moveable longitudinally to the extent of the slotted apertures  520 , as described further herein. 
         [0082]    With reference now to  FIG. 22 , locking mechanism  492  will be described. As shown in  FIG. 22 , cross bar  482  includes an aperture at  482   a  and has an undercut portion at  482   b.  The locking mechanism is comprised of O-rings  530 , a rod  532 , a locking cam  534  and fasteners  536 ,  538 . Rod  532  has an aperture at  532   a  and a flattened surface at  532   b.  Locking cam has an eccentric lobe at  534   a  and an aperture at  534   b  having flattened inner surfaces at  534   c.  Fastener  536  has flattened surfaces at  536   a.    
         [0083]    Thus, once the rear suspension  420  is positioned on the motorcycle frame, the rear suspension can be moved rearwardly to tighten the chain whereupon the threaded fasteners  528  can be tightened to the position to retain sliding mounts  490  relative to bars  488 . At this point, the O-rings  530  can be received over each end of the cross bar  482  and be received in the undercut portion  482   b.  Rod  532  is then received into aperture  482   a  and locking cams  534  are positioned over the ends of rod  532  aligning the flattened surfaces  532   b,    534   c.  Fasteners  536  may be received in aperture  534   b  and fasteners  538  may be brought into threaded engagement with threaded apertures  532   a  of rod  532 . Two wrenches may now be used to bring the locking mechanism into a full locking condition, for example, a box wrench or adjustable wrench may be used with fastener  536  whereby a torque may be applied to the locking cam  534  to position it against the sliding mount  490 . At the same time, a second wrench such as an allen wrench may be used to tighten the fasteners  538  to bring the locking mechanism in a fully locked position. 
         [0084]    This is shown in diagrammatic form in  FIGS. 25A and 25B  where in the position of  FIG. 25A  sliding lock  490  is moved to the full left position into the direction of arrow A and locking cam  534  is rotated in the counter-clockwise direction until it abuts the end of sliding  490 . In this position, a distance between the center of the mounting member  526  and the fastener  538  is a distance D 1 . With reference now to  FIG. 25   b,  the sliding mount  490  is moved to the fully right hand position in the direction of arrow B and locking cam  534  is rotated in a clockwise position to accommodate the lateral movement of the locking mount  490 . The corresponding distance in this position is D 2 , where D 1  is greater than D 2 . 
         [0085]    With reference now to  FIGS. 26-39 , bumper assembly  470  will be described in greater detail. As opposed to the first embodiment of rear suspension  20  where the bumper assembly  170  was provided on the slide rail, and the control arm rotated into the bumper assembly, this embodiment is exactly the opposite; that is, the bumper assembly  470  is mounted to the control arm  430  and the movement of the control arm downwardly provides contact between the slide rail  424  and the bumper assembly  470 . 
         [0086]    As shown best in  FIGS. 27-29 , the control arm  430  includes two arm members  550  ( FIG. 29 ) with a lower coupler  552  which mounts to a link assembly  554  ( FIG. 26 ) and an upper coupler at  560  which couples to side panels  426  ( FIG. 26 ). Rear control arm  430  further includes a mount or bracket at  562  having a base portion  564  with an aperture  566  extending therethrough. Bumper assembly  470  is substantially similar to bumper assembly  170  including a plunger  582 , spring grommet  584 , fastener  592  and washer  594 . The fully assembled position of the bumper assembly  470  is shown in  FIG. 27  where plunger  582  is positioned through spring grommet  584  with fastener and washer positioned against base portion  564  and fastener  592  threaded into threaded engagement with threaded aperture  590  ( FIG. 28 ). 
         [0087]    As shown in  FIG. 30 , in this embodiment, when rear control arm  430  rotates in the direction downwardly in the direction of arrow C, plunger  528  contacts an upper edge  424   a  of slide rail  424 . The extent of travel upwardly of plunger  528  is shown by the difference between the plunger  528  in solid lines versus plunger  528  in phantom lines. 
         [0088]    With reference now to  FIGS. 31-40 , a third embodiment of a rear suspension will be described. With reference to  FIG. 31  a third rear suspension is shown at  620  having a frame  622 , slide rails  624 , top tunnel portion  625 , side panels  626 , a front control arm  628 , rear control arm  630 , front shock absorber  632  and rear shock absorber  634 . A progressive rate linkage  635  is coupled between the rear control arm and the frame as described herein. As in the first embodiment, rear suspension  620  includes an input drive  660 , belt drive  662  coupled together by way of chain case  664 , and a chain tensioner  666 . With reference now to  FIGS. 32-34 , frame  622 , side panels  624  and top tunnel  625  will be described in greater detail. 
         [0089]    With reference first to  FIGS. 33 and 34 , frame  622  is shown as a unibody construction having an elongate frame member or spine  700  with a generally rectangular cross-section. Spine  700  has side walls  702  with a front-end at  704 , a rear end at  706 , a lower wall  708  and a top wall  710 . Frame member  700  could be manufactured from one or multiple sheets of rigid material such as aluminum or steel where portions of the sheet are stamped and formed into the box-shaped configuration shown in  FIGS. 33 and 34  and bonded together such as by welding or industrial adhesives and the like. Frame member  700  could also be manufactured from a casting, such as an aluminum casting. 
         [0090]    Side walls  702  include an enlarged aperture  720  extending therethrough encircled by apertures  722 . Apertures  720  is profiled to receive input drive  660  ( FIG. 31 ) and attached thereto by way of fasteners through apertures  722 . Frame  622  further includes four cross bars; a first cross bar  726 , a second cross bar  728 , a third cross bar  730 , and a fourth cross bar  732 . Each of the cross bars  728 - 732  include threaded apertures  728   a,    730   a,  and  732   a  respectively. 
         [0091]    As shown best in  FIG. 33 , a portion of chain tensioner  666  ( FIG. 31 ) is defined by a unitary member  740  which may be a casting or forging of metal or aluminum which includes a body portion at  742  having two coupling members  744  and  746  encircling the cross bars  726  and  728 . As shown, a portion of cross bar  728  protrudes beyond the coupler  744  whereas coupler  746  encapsulates an end portion of cross bar  726 . Couplers  744  and  746  may be coupled to their corresponding cross bars  728 ,  726  by such means as industrial adhesives, fasteners or welding. Extension bars  750  extend forwardly from couplers  746  and include elongated apertures at  752 . Chain tensioner  666  further includes slide mounts  756  ( FIG. 31 ) having apertures at  758 . Chain tensioner  666  operates in substantially the same way as chain tensioner  466  with the only difference being in the location of the slotted apertures  752 . 
         [0092]    With reference again to  FIG. 32 , right side panel  626  include apertures  626   a,    626   b  and  626   c  which align with corresponding apertures  728   a,    730   a  and  732   a  ( FIG. 34 ). Left side panel  626  includes a large aperture  762  to receive the chaincase  664 , and apertures  730   a  and  732   a.  Right side panel  626  includes an aperture  764  for receiving an opposite end of belt drive  662  ( FIG. 31 ). Each of the side panels  626  also include pairs of apertures  770   a,    770   b  and  772   a,    772   b  for coupling of the suspension as provided herein. Side panels  626  also include a plurality of apertures  774  for coupling of the top panel or tunnel portion  625 . 
         [0093]    As shown in  FIG. 32 , top panel  625  includes a stamped and formed piece of material such as aluminum or steel with a generally flat portion at  780  having folded flaps  782  at the marginal edges thereof. Inclined portions at  784  lead into top panel portions  786  having a slot  788  extending therebetween. The marginal edges  782  includes a plurality of apertures at  782   a  for coupling with the plurality of apertures  774  in side panels  626  to retain the top panel  625  to the side panels  626 . At the same time the slot  788  allows the top panel portions  786  to flank the frame portion  622  as best shown in  FIG. 31 . 
         [0094]    With reference now to  FIGS. 35-38 , progressive rate linkage  635  will be described in greater detail. With reference first to  FIG. 38 , rear control arm  630  will be described having a lower coupler  790  having openings at  792  with frame members  794  extending upwardly and forwardly terminating in couplers at  796  having openings at  798 . Midway up frame members  794  are two bracket members  800  having a portion  802  mounted to the frame member  794  and a portion  804  depending downwardly therefrom having a front aperture at  806  and a rear aperture at  808 . 
         [0095]    The mounting of rear control arm  630  to slide rails  624  is done by way of a link assembly  810  having a tubular portion  812  having threaded apertures at  812   a  and an upstanding bracket at  812   b  having apertures at  812   c.  An axle  816  is provided having threaded apertures at  816   a.  Thus, coupler  790  is coupled to brackets  812   b  by positioning axle  816  through coupler  790 , and by aligning apertures  816   a  and  812   c  together, whereupon fasteners  818  and washers  820  can couple control arm  630  to link assembly  810 . That combination may be coupled to the slide rails  624  by positioning a fastener (not shown) through apertures  822   a  ( FIG. 35 ) and threadably engaging threaded apertures  812   a.    
         [0096]    A triangular link assembly  830  is shown in  FIG. 35  coupled to bracket  800 . As shown in  FIG. 38 , triangular link assembly  830  includes a triangular link  832 , an adjustable link  834  and an axle at  836 . As shown best in  FIG. 38 , triangular link  832  has three pivotal points at  832   a,    832   b  and at enlarged opening  832   c.  Adjustable link  834  includes a shank portion at  834   a  and a coupler at  834   b.  Shank portion  834   a  includes a threaded aperture at  834   c  and coupler  834   b  includes an opening at  834   d.  Adjustable link  834  also includes a ball joint portion  834   e  having a ball joint with an aperture at  834   f.  Adjustable link is assembled by threading nut  834   g  onto threaded portion  834   e  and then threading threaded portion  834   e  into threaded aperture  834   c.  It should be appreciated that the linear length of the adjustable link  834  may be adjusted by the location of the lock nut  834   g  relative to the shank portion  834   a.  Adjustable link  834  is now positioned over axle  836  with bushings  838  positioned in apertures  834   d.  Couplers  840  may now be slidably received over axle member  836  and against coupler  834   b  and locked in place. 
         [0097]    Axle  836  may be coupled to slide rails  624  by inserting a fastener (not shown) through apertures  822   b  ( FIG. 35 ) and aligning them with the apertures  836   a  ( FIG. 38 ). It should be appreciated that ball joint opening  834   f  is coupled to triangular link aperture  832   a  by way of a fastener  832   d.  It should also be appreciated that aperture  832   c  of triangular link  832  is coupled to aperture  808  of bracket  800 . To that end, aperture  832   c  receives bearings  850   a,  spacer  852   a,  grommets  854   a  and washers  856   a.  That assembly is then positioned relative to aperture  808  of bracket  800 , whereby fasteners  858   a  may be received through apertures  808  and threaded into spacer  852   a.    
         [0098]    Linkage  635  further includes a link  870  having a coupler  872  and  874 . Coupler  872  may be coupled to aperture  832   b  of triangular link  832  by positioning bearings  850   b  in each of the couplers  872  and  874  followed by spacers  852   b  and washers  856   b.  A fastener  858   b  may then be positioned into aperture  832   b  through the spacer  852   b  and coupler  872  and into a threaded aperture on the opposite side of the triangular link  832 . 
         [0099]    Linkage  635  further includes a link  880  having a lower coupler at  882  having an aperture at  882   a  and two link arms  884  having apertures at  886  and  888 . Link  870  is coupled to link  880  by way of a fastener  858   b  extending through aperture  888  of link  880  and through bearing  850   b,  spacer  852   b,  washers  856   b  and coupling opening  874  of link  870 . Meanwhile, link  880  is coupled to bracket  800  by positioning bearings  850   c,  spacer  852   c,  grommet  854   c  and washer  856   c  in aperture  882   a,  whereupon a fastener  858   c  may be received through opening  882   a  of link  880  and through aperture  806  of bracket  800 . This couples both the triangular link  832  and the link  880  to the bracket  800 , with the link  870  coupled between the triangular link  830  and link  880 . 
         [0100]    Finally, shock absorber  634  may be installed in the assembly. Shock absorber  634  includes a coupling at  634   a  which couples to aperture  886  of link  880 . Upper end of shock  634  includes a coupling  634   b  coupled to an axle member  900  ( FIG. 36 ) which is shown in  FIG. 35  as coupled to an inside of side panels  626 . Namely axle  900  includes brackets  902  having apertures at  902   a  which may receive fasteners therethrough and into side panel  626 . 
         [0101]    In operation, and with reference to  FIGS. 36 and 37 , when the control arm  630  begins to rotate in a downward sense, triangular link  832  will rotate about bracket  800  causing link  870  to push the link  880  forward. As link  870  is coupled to a midpoint of link  880 , the shock is compressed or stroked at a greater rate than it would with a direct connection. This is also shown diagrammatically in  FIGS. 39 and 40  where control arm is moved from the position shown in  FIG. 39  to a collapsed position shown in  FIG. 40 . This movement causes triangular link  832  to rotate in the clockwise sense (as viewed in  FIGS. 39 and 40 ) which causes link  870  to push link  880  forward and due to the connection of the shock  634  to the upper end of link  880 , the shock is stroked at a greater rate and at a progressive rate. 
         [0102]    Alternatively, and with respect to  FIG. 36A , adjustable link  834  could be coupled directly to the tubular portion  812  of link assembly  810 . 
         [0103]    With reference now to  FIGS. 41-43 , the application of the chain case  664  to the belt drive  662  will be described in greater detail. As shown best in  FIG. 41 , chain case  664  includes a drive portion  920  and a cover  922 . Drive portion  920  includes housing  924  having an outer flange  926  that overlaps opening  762  and a reduced profile portion  930  ( FIG. 43 ) which protrudes through opening  762 . 
         [0104]    As shown best in  FIG. 42 , input drive  660  includes a sprocket  934  having an output coupler  936  for coupling to input driveshaft  938  of chain case  922 . A drive sprocket is shown as coupling to a sprocket  940  which is driven by a belt or chain. A driven sprocket  942  is coupled to the drive sprocket  940  which in turn drives belt drive  662  by way of a drive shaft  944  to sprockets  946 . An idler roller  950  is shown having a tensioner  952  for tensioning the chain or belt. Drive shaft has a shaft coupling  954  which couples to a bearing  956  mounted on an inside of side panel  626 . 
         [0105]    Due to the compactness of the suspension frame  622 , the volume of space beneath the frame  622  is open, which allows the belt drive  662  as assembled to the drive portion  920  (as shown in  FIG. 42 ) to be installed through the opening  762  and under the frame  622 , to a position where shaft coupling  954  couples to the bearing  956 . Drive portion  920  may be coupled to side panel  626 , by way of a fastener  960  positioned through aperture  962  and threadably engaged with threaded aperture  728   a;  as well as with fasteners  964  (such as rivets) positioned through aperture  968  and engaged with aperture  762   a.    
         [0106]    With reference now to  FIG. 1 , the location of the drive axis of the belt drive is shown as A 1 , where a vertical distance from the top of the foot peg  38  to drive axis distance A 1  is shown as Y, and a horizontal distance from the center of the foot peg  38  to drive axis A 1  is shown as X. An attempt has been made in the embodiments herein to move the drive axis A 1  up out of the snow of the snow as much as possible for deep snow applications. Thus for the embodiments of  FIGS. 7 and 31 , the dimension X is in the range of 6.222″ to 7.922″ and more specifically in the range of 7.000″-7.500″. In the embodiment shown X=7.422″. For the embodiments of  FIGS. 7 and 31 , the dimension Y is in the range of 3.400″-5.400″ and more specifically in the range of 3.750″-4.500″. In the embodiment shown Y=3.900″. 
         [0107]    Thus, as the foot peg  38  locates the rider, an attempt has been made to keep the distance Y to a minimum. As the foot peg  38  tends to dictate the location of the rider, the distance X was selected to center the driver&#39;s mass with the mass of the vehicle. 
         [0108]    Although a chain case is shown in the embodiments of  FIGS. 7, 19 and 31 , a belt drive could be used such as that shown in U.S. Pat. No. 8,919,477, the subject matter of which is disclosed herein by reference. This belt drive is designed to not require a tensioning device, such that the belt drive of U.S. Pat. No. 8,919,477 could replace any of the aforementioned chain cases  164 ,  464 , and/or  664 . 
         [0109]    While this invention has been described as having an exemplary design, the present invention may be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains.