R1100GS and R1100RS Final Drives Compatible?

[JimMoore]

Folks,

I'm trying to put together a list of spares for a little trip next Summer. From the MaxBMW fiche, the final drives for the R1100GS and 1100RS have different part numbers. They also have different gear ratios. If that's the only difference it makes me wonder if I can bolt a GS final drive on an RS or vice versa in the event of emergency. Does anyone know?

Thanks,

Jim Moore
Jax, FL

[bikerfish1100]

Jim-
not 100% positive, but i believe that they will physically swap betwixt one another. Those FD ratios are the likely reason that the PNs are different. Highly unlikely that BMW would bother to put different connecting pieces in there, or changes in th casting- as that would then also require differences in the drive shafts, etc. Don't see that happening.
One resulting issue, which would be relatively minor in the big scheme of things, would be that given different final ratios, your speedo would be inaccurate; which is to say "even more inaccurate than it currently is."
Now- don't tell me that you're planning on a road trip, and intend to carry a spare pumpkin around the country with you in the unlikely eventuality of a total and complete FD melt-down, are you? You were just wondering about the viability of having a spare shipped to you on the road in case you met Mr or Ms Disaster in your travels, right?

[JimMoore]

Now- don't tell me that you're planning on a road trip, and intend to carry a spare pumpkin around the country with you in the unlikely eventuality of a total and complete FD melt-down, are you? You were just wondering about the viability of having a spare shipped to you on the road in case you met Mr or Ms Disaster in your travels, right?
Yeah, I figure I'll buy one, have it boxed up with the appropriate tools, and have Mrs. Moore ship it to me one-day-air if I have a breakdown somewhere. I'm also considering the possibility of simply bringing a big final drive bearing and attempting a roadside repair if necessary. What do you thinK?

I'm collecting a bunch of spares. The tough thing is trying to figure out what to bring and what to leave for shipping.

[bikerfish1100]

to do that job, you need to get the pumpkin off to open it up. "off" requires heat to break the loctite on the pivot pins. "open" requires a jig to hold the FD, and about 150-180 lb ft of torque to break the big nut free.
no, this is not a "roadside repair"- unless the road you fortuitously break down upon is right next to a BMW shop, or someone properly equipped is within Anonymous distance.

personally- i would do all necessary maintenance before leaving, tidy up any known litle concerns that might grow into big concerns.... and then not worry about it at all, have a great time, and carry a credit card with big limits and little balance.

[JimMoore]

Check out page 2 of this thread on advrider:

http://www.advrider.com/forums/showthread.php?t=87214&page=2

Of course, he's Steptoe and I'm me, so there's a huge difference there.

[kgadley01]

One good thing about having a spare is that part will never break. :thumb

[PGlaves]

The mechanical bolt-up will be identical from most years. Be sure the brake disk mounts thesame way. RS is on wheel. Don't know about the GS. Also make sure the ABS sensor mount is the same.

Swapping the drive can be done on the road - you must have a good 12mm allen socket, sizable breaker for that socket, and a propane torch to heat the pivots. And a rag to prop up the driveshaft front half when you reinsert the FD and rear shaft-half.

I carry the allen socket. You can usually buy or borrow a propane torch and 1/2 drive bar if you have to.

I would also do an emergency (get me home) big bearing replacement on the road. The case cover comes off with 6 7mm allen bolts and then the entire crownwheel comes off with it - don't drop it. Heat to remove cover - then heat to remove bearing. Assemble in reverse.

Shimming ought to be measured, but as a get-me-home I would use the old shimming and send it off or take it in when I got home. Thoroughly flushing any grit out of the case and around the pinion is the other essential difficult thing.

[bikerfish1100]

thanks for the tips Paul. I guess the lesson here is "where there's a busted-up FD, there's a way to get it home"

[brainfish]

the speedo runs from the front wheel on rt & rs & r's I do not know aboput a gs but I would guess so

[amiles]

Yeah, I figure I'll buy one, have it boxed up with the appropriate tools, and have Mrs. Moore ship it to me one-day-air if I have a breakdown somewhere. I'm also considering the possibility of simply bringing a big final drive bearing and attempting a roadside repair if necessary. What do you thinK?

I'm collecting a bunch of spares. The tough thing is trying to figure out what to bring and what to leave for shipping.


Reading your post I am wondering if your concern is based on any actual signs of deterioration of your present drive? Or are you a consummate belt and suspenders type of guy?

If you are seeing signs that suggest disaster you should bite the bullet and do the work now rather than fear it your entire trip. If no bad signs are present your shipping plan sounds very good, and should be food for thought for the rest of us.

[JimMoore]

Reading your post I am wondering if your concern is based on any actual signs of deterioration of your present drive? Or are you a consummate belt and suspenders type of guy?

If you are seeing signs that suggest disaster you should bite the bullet and do the work now rather than fear it your entire trip. If no bad signs are present your shipping plan sounds very good, and should be food for thought for the rest of us.
Nah, everything is running great right now. It's just that I don't get the chance to do this type of thing very often, and I don't want to spend six days of my two week vacation in Amarillo waiting on a final drive.