RTP final drive for non-RTP

[CoarsegoldKid]

I need a final drive for my 2005 RT.  It needs a bearing rebuild.  A buddy has a final drive sitting on his work bench.  If I remember the ratio correctly the final drive on the RTP is "lower geared" than the civilian RT. Lower gearing would be a benefit when loaded with luggage.  I was wondering what else the result would be to put a RTP final drive on my RT.  Would it mess with the computer or the ABS?

[dirtrider]

1 hour ago, CoarsegoldKid said:

I need a final drive for my 2005 RT.  It needs a bearing rebuild.  A buddy has a final drive sitting on his work bench.  If I remember the ratio correctly the final drive on the RTP is "lower geared" than the civilian RT. Lower gearing would be a benefit when loaded with luggage.  I was wondering what else the result would be to put a RTP final drive on my RT.  Would it mess with the computer or the ABS?

 

 

Afternoon Joe

 

There were a few different RT-P final drives so knowing  the ratio would tell us a lot.

 

As far as effecting the ABS?-- the drive ratio itself will have no effect as it's wheel speed input that  counts. So (IF) it will effect the ABS is based on the pulses-per-mile that the final drive speed sensor inputs into the ABS system. And (THAT) would depend on the number of teeth on  the final drive internal tone ring  (unfortunately I don't know offhand if the RT-P & the standard RT use the same tooth count internal tone ring. (You could probably mark a tooth on both final drives then spin the spool 1 complete revolution while looking into the speed sensor hole then counting the number of teeth as they pass the hole). If the tooth count is the same then that drive should work OK with your ABS. As long as the other final drive is also the early I-ABS era drive & not the later I-ABS gen2 era final drive (pre 08/2006 final drive).

 

Final drive gear ratio is marked on the bottom of the drive casting__  Divide the larger number by the smaller number to get the  ratio.  Picture shows 34/13 so that is a 2.61 ratio.

 

 

 

 

 

 

 

[CoarsegoldKid]

Thanks DR, I saw the markings on the housing I just don't remember what it was.  I'll see it tomorrow and give it another check to make sure I don't hear anything.   I'll get back with more info.

[dirtrider]

11 hours ago, CoarsegoldKid said:

Thanks DR, I saw the markings on the housing I just don't remember what it was.  I'll see it tomorrow and give it another check to make sure I don't hear anything.   I'll get back with more info.

 

Evening Joe

 

Find out what year bike the other final drive came out of.

 

You might also find out if the spare drive has the steel wheel flange. If the spare drive needs the steel wheel flange installed yet (still has the alloy one)  then that might help your decision as BMW probably won't  honor the recall on the replacement drive's wheel flange  if it has already been done on your bike.

 

Swapping the wheel flange at home is a pain.

[CoarsegoldKid]

I checked on the RT-P drive and only the housing is usable plus it's a 33/12 so RT-P lower drive ratio would not have the right tooth count for proper ABS function.  Thanks