The New And Improved Unofficial R65 Forum V2

Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: Breezerider on May 29, 2009, 08:24:47 PM

Title: Possible to change gear ratios?
Post by: Breezerider on May 29, 2009, 08:24:47 PM

I'd like to change the gear ratios on my '79 R65 and heard that at one time racing gears were available.  5th gear is more like an overdrive and I'd like to drop 3rd and 4th gear down a notch.  Are gear swaps done on the early 5 speeds?

Title: Re: Possible to change gear ratios?
Post by: Bob_Roller on May 29, 2009, 09:19:18 PM

Haven't seen any information on successful swaps of gears .

You may want to make a posting on Boxerworks, someone there may be able to give you some guidance on this .

Title: Re: Possible to change gear ratios?
Post by: benita on May 30, 2009, 01:09:25 PM

Have you considered expirimenting with different rear drive units?You can get similar results going this route.

Title: Re: Possible to change gear ratios?
Post by: nhmaf on May 30, 2009, 11:23:45 PM

As you've got a '79 R65, you could probably swap out your 3.44 (31/9) or 3.56 (32/9) final drive with that of an R80/7, or R80RT from the early 80s,  which I think came standard with a 3.37 or 3.3 final drive ratio.   Of course, you'd need to swap the speedo to get accurate speed and odometer readings, too.  Final drive swapping is the "quick and easy" (and much cheaper) way to change the gearing on these bikes.   I don't think that I'd go any 'taller' on the final drive ratio than this, though.  The R100 of the period that had taller ratios (3.2:1 or 3:1) had much more torque and could pull that gearing effectively, which your R65 won't, especially if 2-up.

Title: Re: Possible to change gear ratios?
Post by: Justin B. on May 30, 2009, 11:32:54 PM

I think the only "different" gears I've ever seen discussed have been an overdrive 5th gear to replace the stock 1:1 fifth gear.