Abstract:
A motorcycle modification kit, primarily for Harley Davidson frames, having an oversized wide swing arm for pivotal mounting to a motorcycle frame for supporting a rear wheel having a wide series rear tire. The invention uses offset spacers for the transmission pulley and brake rotor such that the tire remains aligned along the center line of the motorcycle.

Description:
This application claims benefit of Provisional application No. 60/116,044 filed Jan. 14, 1999. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     This invention relates generally to kits and components thereof for retrofitting motorcycle factory frames with wide rear tires. Specifically, this invention relates to such kits and components for retrofitting such frames with true center wide drives and rear tires. 
     2. Related Art 
     It is known in the art of motorcycle maintenance that wider rear tires can be installed by modifying the rear swing arm for the motorcycle&#39;s rear wheel. However, these shop modifications are often done to inexact specifications, posing safety hazards. Further, these modifications to the swing arm only do not compensate for misalignment of the rear wheel and tire caused by inherent offset. For example, the Desrosiers 5,996,718 patent discloses a swing arm for customizing the rear wheel of a motorcycle using a triangular shaped swing arm typical to Harley-Davidson Softail™ motorcycles. However, the Desrosiers &#39;718 patent does not compensate for the inherent offset orientation oblique to the motorcycle centerline. This causes the front and rear tires to be aligned on different center lines, resulting in poor stability and balance. It would therefore be a new and useful improvement over prior art for an after-market modification kit to include both a wider rear swing arm for the rear wheel and an offset transmission pullet to move the drive belt/chain outward t allow even swing arm spacing on both sides of the rear tire. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a top view of the drive kit and components. 
     FIG. 2 is the top view of the wide swing arm. 
     FIG. 3 is an isometric view of the drive kit and components 
     FIG. 4 is a side view of the offset pulley. 
     FIG. 5 is a top view of the offset pulley, the strut spacer, and the offset brake rotor spacer. 
     FIG. 6A is a cross-sectional view of the assembled strut spacer taken along line  6 A— 6 A of FIG.  6 B. 
     FIG. 6B is an exploded view of the strut spacer. 
     FIG. 7 is a side view of the offset brake rotor spacer. 
     FIG. 8 is a top view of a motorcycle showing the wider rear tire aligned along the center line of the motorcycle. 
     FIG. 9 is a cutaway view of the motorcycle transmission and the widened frame cross-member. 
    
    
     DESCRIPTION OF THE INVENTION 
     The True Center Wide Drive for Motorcycles is shown generally in FIG. 1 as  10 . The Drive  10  comprises a wide swing arm  20 , offset pulley  30 , strut spacer  60 , and offset brake rotor spacer  50 . 
     The wide swing arm  20  is shown in FIGS. 1,  2 , and  3 . Wide swing arm  20  comprises two legs  22  joined by a leg connecting member  24 . Preferably, leg connecting member  24  is of uniform thickness. Importantly, leg connecting member  24  is wider than the corresponding piece in factory made frames. The wider length enables wider rear tire  21  to be placed inside of the wide wing arm  20 . Of course, a wider swing arm  20  will require a longer rear axle  150 . 
     Offset pulley  30  is shown in FIGS. 1,  3 , and  4 . Offset pulley  30  includes an inner surface  31 , an outer surface  32 , an offset  33 , a main drive gear hole  34 , and a transmission sprocket surface  35 . Offset pulley  30  is generally cylindrical in shape. Pulley inner surface  31 , once installed, is adjacent to the motorcycle&#39;s transmission  29  so that pulley outer surface  32  is proximate the exterior of motorcycle  74 . Adjacent the pulley inner surface  31  is the offset  33 . Intermediate the offset  33  and the pulley outer surface  32  is the transmission sprocket surface  35 . The main drive gear hole  34  is located through the pulley inner surface  31  and the offset  33 . 
     In typical pulleys, the corresponding pulley inner surface is flush with the inner side  36  of the transmission sprocket surface  35 . Offset pulley  30  includes offset  33  which provides an additional spacing  37  between the inner side  36  and the pulley inner surface  31 . Thus, typical pulleys do not include the offset  33  or the additional spacing  37 . 
     Offset pulley  30  may also be adjustable so that offset  33  can be moved in relation to pulley inner surface  31  thereby changing the additional spacing  37 . In this embodiment, offset  33 , including pulley inner surface  31 , can be removed and are separate from the remainder of offset pulley  30 . The offset  33  is locked into place to the remainder of the offset pulley  30 , thereby also defining a specific spacing  37 , by releasable locking means which may comprise set screws, splined, threads, or key ways. 
     Offset brake rotor spacer  50  is shown in FIGS. 1,  3 ,  5 , and  7 . Rotor spacer  50  is annular in shape and includes an inner surface  51  and an outer surface  52  that also defines a spacing  58 . Rotor spacer  50  also includes a plurality of countersunk wheel holes  53 , a plurality of adapter rotor holes  54 , and a lip  55 . When attached, rotor spacer inner surface  51  is adjacent to the wider motorcycle tire. A plurality of first bolts  56  are inserted through the countersunk wheel holes  53  and into the original brake rotor bolt holes on rear wheel  28 . Thus, the brake rotor spacer  50  is attached to the tire. It is important that the wheel holes  53  be countersunk so that rotor spacer outer surface  52  can fit flush with the rotor. Lip  55  extends outwardly from the rotor spacer outer surface  52  and provides center alignment to the rotor as the tire rotates. The rotor fits flush with rotor spacer outer surface  52 . A plurality of bolts  57  are inserted through the original rotor holes and into the plurality of adapter rotor holes  54 . Thus, the rotor is attached to the offset brake rotor spacer  50 . 
     It is noted that rotor spacer  50  in FIGS. 1 and 3 includes five holes and that it includes ten holes are included in FIG.  5 . For the embodiment of FIGS. 1 and 3, it is understood that holes  54  and holes  53  may comprise the same holes and that bolts  57  and bolts  56  may comprise the same bolts so that such bolts are inserted through the rotor through the rotor spacer and into rear wheel  28 . Countersinking is not necessary in this embodiment. FIG. 5 illustrates the embodiment including different holes,  53  and  54 , and bolts,  56  and  57 . 
     Strut spacer  60  is shown in FIGS. 5,  6 A,  6 B and  9 . Strut spacer  60  is attached to frame cross-member  59  of the motorcycle. Strut spacer  60  includes an inner cylindrical element  61 , and two opposing semi-cylindrical outer elements  62 . The two outer elements  62  are identical to each other, and each includes a hole  63  proximate each of its two ends. Inner element  61  and outer elements  62  are sized and constructed so that the inner element  61  can snugly fit within the outer elements  62 . In other words, the two outer elements  62  together form a generally cylindrical shape that completely surrounds the inner element  61 . When surrounded, the inner element outer surface  64  should abut the inner surface  65  of each outer element  62 . The inner element  61  should be shorter in length so that, when the inner element  61  is surrounded by the two outer elements  62 , the inner element  61  is located intermediate the holes  63  and does not obstruct such holes  63 . In addition, when the inner element  61  is surrounded by the two outer elements  62 , the holes  63  on corresponding ends of the two outer elements  62  should align. Once aligned, bolts  66  should be inserted through the holes  63  and should be tightened with nuts  67 . Upon tightening, the inner element  61  will be securely held in place within the outer elements  62 . 
     Inner element  61  includes a length  100 . Length  100  is the additional width that is necessary to enable the reception of wider rear tire  21  and rear fender by the struts and wide swing arm  20 . Essentially, the struts spacer  60  widens the distance between the struts of motorcycle  74  in order to enable wider rear tire  21  and fender to fit. However, once the distance between the struts is widened, several components, including the original rotor, the original pulley, and the original swing arm, of the original drive are also not properly aligned. Thus, the wider swing arm  20 , which includes the additional width, is installed instead of the original swing arm. In addition, the offset pulley  30  is installed instead of the original factory pulley. And the rotor spacer  50  is installed in between rear wheel  28  and the rotor. 
     Drive  10  allows for the centered installation of wider rear tire  21  because [1] the wider swing arm  20  is also centered onto rear wheel  28 ; and [2] the distance of rotor spacer spacing  58  is substantially equal to the distance of offset spacing  37 . Thus, rotor spacer spacing  58  and offset spacing  37  each encompasses one-half of the total additional width necessary to enable the installation of wider rear tire  21 . And, because the rotor spacer spacing  58  is at one side of the wider rear tire and the offset spacing  37  is at the other side of wider rear tire  21 , equal spacing at each side of wider rear tire  21  is achieved which results on the centering of wider rear tire  21  along center line  23 , as shown in FIG.  8 . 
     Other components of motorcycle  74  may also have to be spaced out of their original location in order to allow the insertion of wider rear tire  21 . These components include the battery box, which can be offset by the battery box spacers (comprising regular annular spacers with corresponding bolts and nuts); the pulley cover, which can be offset by the pulley cover spacer  120 ; and the muffler mounting bracket, which can be offset by the muffler bracket nut and bolt spacer  140 .