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Old 03-12-2015, 09:37 PM
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Davezilla Davezilla is offline
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Join Date: Mar 2014
Location: San Antonio Texas
Posts: 2,710
Default Re: unique jackshafted bmx/dual suspension drive idea

You could also try using one way bearings to eliminate the parasitic drag if no freewheels are available for your size requirements... These things come in all sizes and configurations so if you got some welding and fab skills, this shouldn't be too hard to come up with a working setup... Just find one that meets your inside and outside diameter needs as well as one that has a fairly high torque rating for the front sprocket since pedaling can produce some pretty good amounts of torque... like a Lot more torque than the engine can produce. For the drive side tho you just need one that can hold about 10 to 15 ft/lb of torque, basically your engine's torque x 4 is what's coming off the output sprocket of a typical China Girl engine since the clutch is reduced 4:1... you'll need to know the friction drive engine's torque output and multiply by the gear ratio to get the right torque rating for the output shaft bearing if a one way is used here.
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