Final Drive Failure

[MikeCam]

Often wondered about real numbers as a portion of the total fleet. When trying to find information about final drive performance, failures, and causes there is often more hysteria than fact.

Here is what I have uncovered lately.

1. Oilheads - all years/all models (both 1100/1150 models) 5% failure rate
2. K-bricks - late model (mostly LT) (mostly 1200 brick series) 6% failure rate
3. Hexheads - all years/all models 3% failure rate

Causes:

1. In many cases of early, low mileage failure the prime cause was bad bearings exacerbated by the inability of the user or service tech to detect any incipient failure - they just went. This is corrected case by case or DIY. The older bearings were substandard metallurgy, sub-contracted out, poor quality control, and NOT subjected to recall. Rather, BMW replace them as they fail.

2. Overweight, overloaded, high stress, high heat, long service interval and or abusive owners. A significant subclass of FD failures fit this mode. High stress equates to wheelies, stoppies, off-road use exceeding the suspension limits of the bike often. High heat equates to long distance runs under heavy loads with inadequate preventive maintenance (fluid changes, rest periods for heat cycles).

3. A significant amount of information indicates that the angle of the Paralever driveshaft on certain models lends itself to failure. LT's are particularly prone to this.

Spline wear, which is predominately related to bad metallurgy, weak engineering design, and performance at the limit of design tolerances shows similar patterns.

BOTTOM LINE - Low failure rate. If yours goes, it is 100%. Only partly preventable, mostly it is simply a weak feature of the BMW design.

HTH

[Biff's R]

Mike,
One thing that I have heard is that using the 75-140 gear oil in the FD could also be a contributing problem. Kind of like putting 90w into the engine. Thicker oil increases pressure, heat, and may reduce the ability to lubricate.

I think that many of the LT and RT bikes are frequently over the suggested GVW.

BTW, on the Maintainence Checklist on in the BMW CD Manual, it only suggests changing the FD Lubricant every 25k or 2 years.

[R601968]

I'm starting to get a bit concerned about reliabilty. I bought this bike for touring piece of mind, starting to lose that peace with all the final drive failures.
The Iron butt rally ends today with far fewer BMW completeing the 11 day event than started, many are out with final drive failure. This is not limited to just the oil head final drives but also the new hex heads. This is becoming more apparent that it is a enginerring flaw.

[Boxer]

Using the Iron Butt Rally as a guide is not an accurate method. These bikes are put under extreme stress for days on end without much maintenance or rest.
Sure, this is a test of the quality of the machine but in relation to normal day-to-day riding, it's no comparison. Any of those bikes that blew the FD could have gone for 100K with no problems under normal conditions...Maybe. The BMWs in the Rally still make up a far greater percentage related to their market share in the US, than any other brand.

It's like saying "that" Ford blew an engine at Daytona so Ford engines are no good. Too much 'deductive reasoning'.

[Dr. Strangelove]

1. Oilheads - all years/all models (both 1100/1150 models) 5% failure rate
2. K-bricks - late model (mostly LT) (mostly 1200 brick series) 6% failure rate
3. Hexheads - all years/all models 3% failure rate

BOTTOM LINE - Low failure rate. If yours goes, it is 100%. Only partly preventable, mostly it is simply a weak feature of the BMW design.

HTH

Interesting stats, but I am surprised that the numbers are that high. I would call a 3-5-6% failure rate is pretty high--not a typo, hunh? Those numbers are not reassuring.

You suggest that there was inferior metallurgy/workmanship in the "older" models. Is 2004 an older model?

Thanks for the info.

John

[ProductUser]

Mike,
One thing that I have heard is that using the 75-140 gear oil in the FD could also be a contributing problem. Kind of like putting 90w into the engine. Thicker oil increases pressure, heat, and may reduce the ability to lubricate.

This is not true. I've been following FD failures for years, especially on the bmwst site, and not one of them has contributed a FD failure to oil viscosity. I have run 75-140 in my FD for 60k miles with no leaks or issues. The same is true re adding moly to the FD to make it last longer; there isn't enough data that supports this claim. The likely cause, if one can even call it that, can be attributed to improper assembly and/or defects in materials.

Here's a link re final drive failures in the 2007 IBR.
http://www.ironbuttrally.com/IBR/2007.cfm?DocID=42

Why stop at the FD? Let's talk about the complexity and the costs for the following systems/maintenance: Servo assisted brakes, ABS unit, required brake and clutch bleeding on ABS equipped bikes, CANBUS system on the hexheads...etc.

For the most part, people come to these forums to seek mechanical help. As such, problems like the FD and the notorious transmission splines, get people in a panic. However, I agree that the FD should be more bullet-proof.

Just ride the bike and deal with these problems as they arise. If you don't like the reliability or the costs associated with BMW's, buy another brand.

Sorry this turned into a rant.

ProductUser

[geothepencil]

How can the new style final drives stand up to 24 hour endurance racing as in LeMans and shorter races in Moto St here in the states (in the great R1200S) and fail at excessive rates in normal (but hard) service in the Iron Butt Rally ? Perhaps the racing shops rebuild between races or measure everything twice in assembly where the production models don't quite have the tolerances. I'm puzzled. As light as I ride, I don't expect one to fail EVER !

Correct me if you know otherwise, but I have never heard of a Yamaha or Honda final drive failure. There must be some.

geo

[DJ Downunder]

The older bearings were substandard metallurgy, sub-contracted out, poor quality control, and NOT subjected to recall. Rather, BMW replace them as they fail.

That's what I was told also...Shame on you BMW....because if your warranty has run out..it's your bad luck.

My service guys have changed heaps of these bearings all have shown substandard metallurgy.

DJ

[zooomart]

[quote="MikeCam"] The older bearings were substandard metallurgy, sub-contracted out, poor quality control, and NOT subjected to recall. Rather, BMW replace them as they fail.

Has the quality of the FD bearings changed over time?
Would a 2004 R1150 have tighter tolerance bearings than 2002 or a R1100 series?

[towerworker]

Boxer--


"Deductive reasoning"..........seems I have heard that before.

[geothepencil]

Well I checked with one of the large racing dealerships who run the new style drive and they are not rebuilt between races and are stock drives. You could call their usage severe. They are puzzled as well as to why so many fail in consumer hands.

I will throw out one remote possibility. Witness the thread the other day where the owner was unhappy with the dealer tech who didn't seem to know how to do the once at 600 mile oil change in the drive and who checked his work only to find out that he had only gotten 50 cc of oil instead of 250 called for. That might make a difference !

geo

[telliott]

Whats the general opinion of replacing the bearing "BEFORE" failure?

I read a post (somewhere) that the new bearing has fewer "balls" than the original. ( Doesn't sound quite right does it??) And that you could make the change using the original shims. Can't locate that post today but as I remember it was from someone who should know, ie: lots of tech posts, etc.

Does anyone know when the change was made?

Any data on the failure rate of the "new" bearing?

24K so far and I was told by the previous owner that it had Synthetic changed at 22K. It looks new and rear end is tight so far.

[ProductUser]

I wonder if the amount of weight placed on the single-sided swing arm, along with the rotational forces at speed, has any affect on failures? Are most failures on RT's, GS's or LT's or R's? Based on what I've read, most failures occur on GS's and RT's. There are been failures on K bikes and our beloved R bikes, but not as much. Again, this is just pure speculation.

Would a two-sided swing arm help?

ProductUser

[DJ Downunder]

I read a post (somewhere) that the new bearing has fewer "balls" than the original.

I also read that....and I asked and they said.."No..That's not true".

I think there is that option with some aftermarket bearings but not recommended by BMW.

And that you could make the change using the original shims.

You can adjust and slop, play or wear...but it will not help if there is a problem with the quality of the bearing in the first place.

My guys (BMW mechanics) did a service on a guys bike who was doing a big round Australia trip..and on spinning his rear wheel while on the center stand they could detect a slight roughness...so the changed his bearing.

They said it's a good thing that they did because it would have gone on him for-sure..(so they say)

They said mine wasn't too bad...(whatever that means)

DJ

[telliott]

I read a post (somewhere) that the new bearing has fewer "balls" than the original.

I also read that....and I asked and they said.."No..That's not true".

I think there is that option with some aftermarket bearings but not recommended by BMW.

[DJ

Well, apparently it is different in the US or you may want to find some other BMW Guys. Here is a cross quote from the BMW message list that came today. Funny they are having the same discussion!? (Yeah, there really isn't a problem.)

<<A data point - for whatever it is worth. I took my 00 R1150GS over for a 48k(at 50k miles) service last weekend at Max's and about an hour or so into the service they came out and said that the final drive bearing was short miles away from failure - they had the part in stock (apparently the
latest/3rd incarnation of the part) and were able to replace it that day (a
long day for the mechanic I guess) - of course it was on my nickel (or lots
of them), but at least it was fixed before failure...>>

[ctRrider]

As part of my own pre-60,000 mile service this April before a trip from the east coast to CA and back, I changed out the crown bearing and seal. I was expecting to get the new 17 ball brearing but instead got the newest 19 ball bearing. BMW has gone back to the 19 ball bearing after trying the 17 ball bearing which replaced the original 19 ball bearing. So I am told. Maybe the new one is from is from a new source.
The old bearing was also 19 balls and showed no signs of wear so I am keeping it as a spare. Of course if I hadn't changed the bearing, I would have been concerned on the trip about the possibility of failure in the middle of god forsaken nowhere.

It was not a tough job to do. Just a couple of standard tools, a heat gun and a freezer to freeze the bearing to put it back on.

10,000 miles and still running. I also change the rear end fluid out every
other oil change just to keep an eye on things.

Tom

[awagnon]

It was not a tough job to do. Just a couple of standard tools, a heat gun and a freezer to freeze the bearing to put it back on.

Doesn't the FD crown bearing have to be shimmed so that the "pre-load" on the bearing is just right? I thought it was different for each bearing and hard to get just right.

As far as the failure rate of FD drives goes; I wish the BMWMOA or RA would survey their readers so there would be some better data.

[ctRrider]

I read somewhere while doing research on how to change the bearing that it was OK to just reuse the old shim. So I did. Knock on wood it is working fine with no evidence of wear in the oil and no play in the wheel.

Tom

[R601968]

Too much deductive reasoning???? What is that. All I was saying is this is a problem that weight to heavy on my mind. If I want to get on my 2004 R1150r with only 20000 milles and head to Alaska from Florida
I want the peace of mind that it will make the trip. I don't think for the price we pay for "quaility engineering" that that is unresonable. If I choose to ride my bike for five days staright and service the bike, then ride again for six days, that a bike with a 36,000 mile warranty should not have a problem.
I personally feel as comfortable riding my 1968 R60/2 across the country as the 2004 R1150R.

[wncbmw]

I personally feel as comfortable riding my 1968 R60/2 across the country as the 2004 R1150R.

If reliability is your main concern, you would be hard pressed to find a more dependable ride than a well-maintained airhead! Lots less to go wrong than a new bike! (computers, electronics, etc.)