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Gear Ratios Changed?
Posted: Sun Aug 06, 2017 12:44 pm
by vroomr
I have an '07 "model release" R1200R. Just to see if some poorly described features were described better in a later version of the owner's manual (they were), I downloaded the 4th edition of the manual, which has a 2010 revision date. I noticed that the primary and all six gear ratios were different in the two books. Did they really change those gears, or did they simply correct the documentation?
Re: Gear Ratios Changed?
Posted: Sat Aug 12, 2017 9:52 pm
by deilenberger
vroomr wrote:I have an '07 "model release" R1200R. Just to see if some poorly described features were described better in a later version of the owner's manual (they were), I downloaded the 4th edition of the manual, which has a 2010 revision date. I noticed that the primary and all six gear ratios were different in the two books. Did they really change those gears, or did they simply correct the documentation?
I really haven't noticed any difference in gearing, and my first R12R was an '07, and the current one is a '12. I do find it a bit easier to take off in 1st gear on the '12 - so perhaps they changed that ratio a bit. What sort of changes are shown?
Re: Gear Ratios Changed?
Posted: Sun Aug 13, 2017 8:54 am
by dbrick
vroomr wrote:Did they really change those gears, or did they simply correct the documentation?
I don't know. One might compare the p/n for the transmission gears in the parts fiches for the '07 with the p/n for the '10. BMW parts fiches can be found at
realoem.com and many dealer websites.
You'd have to look at both pieces of each pair of gears that mesh in the gearbox to create each of the gearbox's six speeds. If the part numbers are the same, I'd assume the gearbox ratios are the same. If, OTOH, the part numbers are different, the ratios may have been altered — "may" because another change to the gear (other than the dimensions of its teeth) may have been put in place.
Re: Gear Ratios Changed?
Posted: Wed Aug 16, 2017 1:13 pm
by vroomr
What sort of changes are shown?
Here are primary, 1st, and 6th. Final drive is the same in both revisions.
From the 2006 printing describing the 2007:
Transmission primary gear ratio 1.824 (31:17 teeth)
Gear ratio in 1st gear 2.277 (41:18 teeth)
Gear ratio in 6th gear 0.805 (29:36 teeth)
From the 2010 revision:
1,737, Primary gear ratio
2.375 (38:16 teeth), 1st gear
0.848 (28:33 teeth), 6th gear
Multiplying 1st & 6th by the respective primaries, I think the 2007 has a slightly lower 1st and a slightly higher 6th (did I do that correctly?). Or, both model years are identical and the documentation is the only thing that changed.