Final drive ratio for '77 R100/7

[Kai Ju]

Quick questions regarding what the final drive ratio is supposed to be for a 1977 R100/7.
Both the Haynes and BMW Factory manual state that it's 34/11 while my bike is equipped with a 32/10.
Max's parts catalog lists 34/11, 34/8, 33/11 and 33/12
It certainly would explain my speedo error.
Who's right ?

[oldroadie]

According to Ian Falloon's Original Bmw Air-Cooled Boxer Twins 1950-1996 book the 32/10 was changed to 34/11 at unit number 6147575.

[CanadaBiker]

Originally Posted by oldroadie

According to Ian Falloon's Original Bmw Air-Cooled Boxer Twins 1950-1996 book the 32/10 was changed to 34/11 at unit number 6147575.

That would explain a lot for me. My bike is one of the first '77 R100 and has the 32/10. Thankfully, my bike has the matching speedo.

(I looked at Snowbum's chart, and it seems to suggest it should be a 33/11)

Originally Posted by Kai Ju

Quick questions regarding what the final drive ratio is supposed to be for a 1977 R100/7.
Both the Haynes and BMW Factory manual state that it's 34/11 while my bike is equipped with a 32/10.
Max's parts catalog lists 34/11, 34/8, 33/11 and 33/12
It certainly would explain my speedo error.
Who's right ?

Kai, besides the speedo error, how do you like the 32/10? I've only put a few miles on mine, but I always wondered if I might want to change it for something taller.

[Kai Ju]

oldroadie, mine is 6140566, sounds like I have an early VIN. Thanks for that tidbit of info.

CanadaBiker, I would like to have slightly taller gearing. On most of my street bikes I've changed the gearing to give me a more relaxed cruising rpm.