Final drive - ok a problem - what to do?

[RavenGS]

Hi all,

Okay, it seems like there is issues with final drives. That said what should those of us whom have not had a problem do to catch it before it goes bad? I'd rather not break down out in the middle of nowhere if preventative maintenance could have prevented.

Any advice or any links for PM to be done on final drive?

RavenGS
Lino Lakes, MN
R1150GS

[MLS2GO]

My dealer recommends changing final drive oil every time you change the engine oil. Many scoff at this, but they believe it makes a difference. If it does, it's a small price to pay.

[ragtoplvr]

There is a bit more to that.

Look at the magnet, there should be a very slight amount of fuzz, if there is a lot of fuzz, then there is a problem. As you know your bike, you learn how much fuzz in 6K miles is normal. More than normal then time to go take a closer look

In addition, every time you check you tire pressure, something I do weekly with gauge, and with a kick before ever ride. You also check for slack. I do this by putting my finger between the caliper and disk, then try to wiggle top of tire. If I feel any movement between the caliper and disk, I order a bearing oring and seal, and park the bike. This check only takes 30 seconds. Not much time to prevent a failure with possible rider injury.

Pulling the bearing takes a machine shop a few minutes. Most bearing splitters are too small or too thick. Other than that, you can change it on the bike, actually labor once you have done it is 2 or 3 hours.

You can use the same shim. Or you can take out the shim, put in a ring of solder, assemble the drive (no seal or oring) and then disassemble, and measure the solder. There is very little if any rebound with solder. Then add the preload to the solder thickness and compare to your shim. If I get at least 40K per repair, I will be as happy as possible, considering this should not happen at all.

Last take your vin and milage and go to the national highway traffic safety site and file a complaint

http://www-odi.nhtsa.dot.gov/ivoq/index.cfm

it is the only way to hope BMW will man up and make a good final drive.

I honestly think there is nothing wrong with the basic design, just sloppy assembly and machine work on BMW part.

Rod

[DarkCloud]

PM ? Change the oil every 6,000 miles

Eliminate mechanical abuse. Speed shifting, power shifting, excessive engine braking, engine lugging. Match engine speed to ground speed when shifting gears. Fast acceleration, and high speed riding all take their toll on the final drive.

Then a contingency plan to put your mind at rest. What will I do if the final drive goes out?

1) Have the bike hauled to the nearest BMW dealer

2) Rent a U Haul van and take it to the nearest dealer or back to my servicing dealer.

3) Buy a dirt farmer pickup truck and haul the bike home.

4) Fix the bike myself on the road. Since the odds of the final drive going south and having a flat tire are about the same why doesn't BMW put a spare final drive on the bike with the tire plugging kit.

5) Trade the bike in

6) Donate the bike to charity

7) Set the bike on fire, or have an accident and let the insurance company sort it out.

[GlobalRider]

Look at the magnet, there should be a very slight amount of fuzz.

Why even a slight amount of fuzz? After the first few thousand miles, I'm not getting any at all with one final drive oil change per year.

I honestly think there is nothing wrong with the basic design, just sloppy assembly and machine work on BMW part.

There is. They used a ball bearing where they should have used a tapper roller bearing.

[nrpetersen]

There is. They used a ball bearing where they should have used a tapper roller bearing. I don't think there is a tapered roller bearing with a bore this large, a cross section this small, yet capable of this much speed in a small gearcase.

It is a serious design problem which has no simple answers.
Mn MechEngr

[aaaaaa]

Simple? simple by choice? Where've I heard that before?
robert

[ragtoplvr]

many other bikes even the bulletproof Honda's use a ball bearing with side load.

The allowed side load is published, and it is part of the reason for non-filling slot deep groove ball bearings.

The issues are either excessive side load from incorrect shimming or

The diameter the inner race is pressed over is machined too large, consuming all the radial clearance, which will make a bearing fail in side load situations, this is the reason the BMW bearing is C3 clearance. Yes, I am sure, in a previous job I went thru a failure analysis where we actually had real Bearing Engineers come in and evaluate the failures, and even then management would not believe them because they bought machines that could not hold the 0.0003 inch total tolerance on shaft and could not ever admit their multimillion dollar purchase was totally wrong.

PS That company is out of business now, hummm must be the Chinese competition, right. Someday I hope we outsource managers.

Rod

[GlobalRider]

I don't think there is a tapered roller bearing with a bore this large, a cross section this small, yet capable of this much speed in a small gearcase.

There isn't in those same dimensions...I've checked. But there are in wider widths.

The rotational speed for a bearing of that size isn't an issue. Side forces on a ball bearing are.

[GlobalRider]

Many other bikes even the bulletproof Honda's use a ball bearing with side load.

Single sided swingarm or full swingarm Hondas?

[ragtoplvr]

They were full swing arm I will admit.

The BMW bearing is huge and the distance between the 2 bearings is fairly large. If the bearing were under designed, all of them would fail. In this case a lot of people have no trouble and others do, which points to tolerance or assembly errors.

However there are Radial Ball Bearings that I think would fit, and they can take a lot more side load if someone has machine shop time and the inclination.

I know on my R1150RS, the part of the ring gear and carrier assembly where that big ball bearing is pressed on is oversize. This is because when the bearing is installed all the radial clearance is used up, in fact the bearing was slightly stiff. I would have machined it down, but the bearing was already on and the setup on my home lathe to take off .0005 to .001 on that diameter is very fiddly. Besides the sun was out.

If the repair lasts another 42K or so I will live with it. If not then I will do something, and then I guess in about 3 or 4 years more I will know if mine is fixed or not. I think the oil head design is actually better than the hex head design with it's extra leak spot just so the inner shaft can be hollow, smaller bearing and pressed on dissimilar metal wheel carrier.

But hey, everyone is entitled to their opinion, and I am not going to spend a lot of my time doing a full analysis of the forces. Besides I no longer have access to that kind of software. However if someone does all that, I would be interested to see the results. I might change my opinion. Or it has been so long my aging brain can no longer process the information. Until then I have my opinion and you have yours, we must simply agree to disagree. OK

At least we agree that Riding is way better than discussing this, RIGHT!

Rod

[GSAddict]

My dealer recommends changing final drive oil every time you change the engine oil. Many scoff at this, but they believe it makes a difference. If it does, it's a small price to pay.

+1 :nod for 250 ml of oil it's hardly worth talking about let alone arguing.

IMHO & experience, failures seem to stem from improper shimming (too tight) at the factory as was the case on mine.

[bmwmick]

There isn't in those same dimensions...I've checked. But there are in wider widths.

The rotational speed for a bearing of that size isn't an issue. Side forces on a ball bearing are.

Exactly! This bearing runs at VERY slow speed....as bearings go.

[RavenGS]

Maybe I should ask this slightly different. I'm quite sure, as with anything, assuring lubrication is there and clean is foremost. What I was questioning however is more about the actual mechanical pieces involved.
There seems to be a lot of discussion about bad bearings, BMW's failure to have quality bearings, and so on. So what I'm questioning is are there particular parts that should be replaced (or cost effective to replace) BEFORE hand which solves the issue? Or stated another way once someone has this repaired is it fairly likely the problem will re-occur or does the new pieces seem to solve the issue permanently?

Thanks, :bow
RavenGS

[GSAddict]

Maybe I should ask this slightly different. I'm quite sure, as with anything, assuring lubrication is there and clean is foremost. What I was questioning however is more about the actual mechanical pieces involved.
There seems to be a lot of discussion about bad bearings, BMW's failure to have quality bearings, and so on. So what I'm questioning is are there particular parts that should be replaced (or cost effective to replace) BEFORE hand which solves the issue? Or stated another way once someone has this repaired is it fairly likely the problem will re-occur or does the new pieces seem to solve the issue permanently?

Thanks, :bow
RavenGS

In my case it took 2 bearing failures for me to question the shimming (after all BMW would not make a mistake like that would they?). On installing the 3rd bearing I actually checked the factory preload and found .005" too much preload. Since then no more problems. That would explain why some fail and some don't.
I do not believe the bearings are at fault. FAG is one of the best manufacturers of bearings in the world.

[JanMiller]

many other bikes even the bulletproof Honda's use a ball bearing with side load.

The allowed side load is published, and it is part of the reason for non-filling slot deep groove ball bearings.

The issues are either excessive side load from incorrect shimming or

The diameter the inner race is pressed over is machined too large, consuming all the radial clearance, which will make a bearing fail in side load situations, this is the reason the BMW bearing is C3 clearance. Yes, I am sure, in a previous job I went thru a failure analysis where we actually had real Bearing Engineers come in and evaluate the failures, and even then management would not believe them because they bought machines that could not hold the 0.0003 inch total tolerance on shaft and could not ever admit their multimillion dollar purchase was totally wrong.

PS That company is out of business now, hummm must be the Chinese competition, right. Someday I hope we outsource managers.

Rod

Interesting, my 04 RT FD bearing failed, it was so tight on the shaft it could not be pressed off, had to be cut off...

[PGlaves]

Interesting, my 04 RT FD bearing failed, it was so tight on the shaft it could not be pressed off, had to be cut off...

Jan,

How hard was it to get a new one on the hub. I'd suspect an oversize bearing before I suspected an undersided bearing inner race.

[RJM2096]

Are final drives really an issue? I had a Honda Magna 85 V65 with a shaft. I sold it it at 20,000 miles. Never a problem. My HD has 12,000 and still running the same belt. My BMW has 40,000 miles and I worry that my FD will fail at 60,000.

Am I being fair? The Honda and HD will be a mess if they ever make 60,000. Do we expect too much from BMW?