drive ratio

[Red1974]

well my swingarm-side final drive splines are toast, so its respline or buy used. Theres a 34/14 final drive on e-bay with WAY better splines than I have, will it work with whatever rear wheel I have, Its a low mile Lester in really good shape. Thanks for any input folks. Red 1974

[boxermaf]

I don't know what model bike you have, but as far as I know, the tallest commercially available final drive ratio for /5 /6 /7 and later road-going BMWs was 2.91 - anything taller/lower numbered would likely be a custom final drive for racing purposes - it would be pretty tall for any airhead to pull with std transmission @ 34/14 = 2.43

[Red1974]

my bad 37/11........I have a 1974 r90/6

[51274]

Sounds pretty unusual to have the splines on the swingarm end of the drive go out (can't that nut be loosened and the drive gear replaced?). Perhaps the seal there is also gone, and the driveshaft oil drained into the rear drive - leaving it unlubricated?

I've got a used 37/11 rear drive unit that had the (lifetime?) Freeman spline conversion done sitting in a box. Came out of an 84 R80RT. If you're in the Chicago area and have an interest - Marty 63zero-291-nine263. Don't have pics handy but can make some if you're interested...

[beemerPhil]

Remember that changing your final drive ratio also changes your speedometer ratio- if you change one without changing the other, your speedometer will be even less accurate than it is now!

[Red1974]

Thanks Phil........no worries about the speedo,it doesn't work! I'm think I'll go with a vapor gps speedo dealie,they're cheap and by all accounts work. Thanks Nils-Red1974