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What Year Did the FD Issues Begin?

ricochetrider

Out There Somewhere
Howdy guys.

As usual, I'm vaguely dreaming of a newer bike.
Currently, I'm watching a 2001 K1200RS on eBay... But all the chit chat about final drive issues really has me spooked. I have older bikes, and never once even heard a whisper about such problems with either the 93 R100RS or the 88 K100. I'm pretty certain I don't want to spend a boatload of money (or even ANY money) on something guaranteed to fail or break.

When Did the FD problems raise their ugly countenance?


ALSO: Once fixed, how likely is it that the FD will fail again?
 
I'd guess they started in 1921. :D
Everything breaks eventually and with a forum like this one, it doesn't take very many similar failures to get any particular issue labeled as common.

There are lots of threads on this, I tried to find one with a survey result table but gave up.

I wouldn't be afraid of that bike you want. Armed with knowledge such as you have, you can specifically check all the things you know to be 'issues' and increase your confidence that way.
 
BMW durability

Actually, BMWs are notoriously durable. That's why they are the chosen brand for so many long-distance tourers. Do the regular maintenance and they will outlast most every other brand of bike. I have owned models from the 1950s, 1970s, 1990s, and 2000s with no reliability or durability issues whatsoever. Ride on!
 
when did the problem begin? right around when the internet made such large scale public discussions commonplace. prior to that, you'd have to hang out in a shop on a near daily basis to hear such chatter.
not discounting the existence of the issue, just the depth and breadth of its being reported.
 
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Since '05, way too many FD implosions (including miltiple failures) have come to light.

While each model year has its nuances as to reliability, since 2005, the FD failures refuse to go quietly into the night, as some might have you think, and are actually being investigated by the NHTSA.

Research what you're interested in, weigh the pro's and con's, and then make your decision.

Don't let me or anyone else make it for you. :nono
 
It's the early Hexheads, right? Not Ks?

nope.

(borrowed from thread on Pelicanparts.com):

"After over 145 individual complaints filed between April 2001 and August
2011, the NHSTA has finally opened its first official investigation into the
failure of crown gear bearings on BMW models equipped with the Paralever
style final drive. NHSTA investigation DP12001 opened 1/20/12 is centered
on 1999-2005 K1200LTs for now."
 
Now I am not saying that we are all idiots, but I do wonder how many people had FD failures due to lack of proper maintenance. It is a mechanical device and honestly fits into the old adage that "Mechanical items will break!"
 
In no particular order for original Paralever (not big hole) final drives

Impact damage from bumps and potholes
Weight in excess of the rated rear axle loading
Oversize hub machining - reduced bearing radial clearances
Improper shimming - reduced bearing angular clearances
Use of improper viscosity lubricants
Side thrust on the ball bearing from gear mesh

and in most cases a combination of at least two of the above contributing factors

The deep groove ball bearing is the same as introduced on the original single sided swingarm on the R80G/S in 1981.

Failures were rare on the SSSA airheads and on the classic K bikes.
By model, the K1200LT and R11xxGS seem to have the most failures
Failures seem rare on R1100RS bikes
Some on RT type bikes

For the "big hole" final drives the issue appears to be primarily a seal leakage issue.

These originated as lifetime fill unvented pressure vessels. Dumb idea. So then they said change oil at 600 miles. Drain through the fill hole. There seems to be reputable evidence than the supplier was leaving the factory run in oil in them, which was supposed to be drained and replaced after bench test run-in.

Then they said maybe a change at 12,000 mile intervals. Good idea. And later rather than sooner they did a change and provided real drain plugs. And I understand that the newest versions have or will have vents.

In my opinion the addition of the vents will eliminate the pressure buildup, and the seal failures for the most part. Then they won't get low on lubricant, and bearing damage becomes much less likely.

Topside estimates across the range seem to be about 4% failure rate, meaning 96% don't fail. I would not let the possibility deter me personally from buying any bike I otherwise wanted. But, I know how to change the bearing that accounts for most of the failures in a motel parking lot with no special tools required except a propane torch and a 7mm allen wrench. Such would get me home for sure and then checking the shimming and/or reshimming is in order.
 
IIRC the BMW KLT Touring forum was keeping or had started to assemble information about failures by individuals - miles, dates, etc.
 
I have heard estimates as high as 17% failure rate. But you have to look at mileage, also.
The maintenance specs were changed, on the R1200s at least. So BMW didn't even know the right maintenance.
The F800s also have a rear axle failure, again with high numbers based on internet world wide communication, but probably only a small percentage.
But there also, BMW did provide a new axle, an axle number superseding the previous number.
dc
 
Now I am not saying that we are all idiots, but I do wonder how many people had FD failures due to lack of proper maintenance. It is a mechanical device and honestly fits into the old adage that "Mechanical items will break!"
From various sources (including a regional rep) there were a few hundred incidences of crown bearing failure and/or crown gear seal failures in the early-to mid-2000's, primarily on the K12LT. The same right-side final drive unit was also used on the oilheads, so some failures there as well. The "rash" of FD failures began ~2000 (BTLivedThroughT). The frequency of failures declined sharply in the latter half of the decade, one assumes because BMW figured out what the issue was, combined with the increasing replacement of the LT-era FD's with the hexhead Big Hole drives.

I'm not aware of any large bearing failures in the newer design drives (there may have been a couple, but the absence of discussion of such failures given the sensitivity of the previous design's problems speaks volumes for the new drives' reliability), and only a handful of seal leaks and an axle interference-fit issue in a few of the early Big Hole drives.

The mothership has never revealed the source of the issue with the previous drives. The most-commonly repeated theory is that many were shimmed way too tight by the supplier, causing premature crown wheel bearing disintegration. If a failed drive is properly shimmed when repaired, they typically don't fail again; if the crown wheel bearing is simply replaced and the cover slapped back on, another failure follows a couple 10K's later.

On the K12RS -- it uses the same FD as the LT, but the number of failures reported on the RS were lower than the LT, likely due to lower loading. If it were me, if I found an RS I liked, I'd buy it and ride it because statistically even the LT-era FD failures are rare (a few percent -- too high to be "acceptable" but not even close to "likely" to happen). If you need peace of mind, pull the final drive off and ship it to Tom Cutter to open and check the shimming -- he claims he's never had a failed FD come back to him.

On the maintenance issue -- that was absolutely not a factor. When we were running surveys on this issue on the LT list, neither maintenance nor oil type or weight was statistically significant. For example, both of my K12LT FD failures were maintained right on schedule, and with BMW's gear oils. I'm one of those that believes the indications all point to a supplier faulty assembly issue.
 
For the "big hole" final drives the issue appears to be primarily a seal leakage issue.

These originated as lifetime fill unvented pressure vessels. Dumb idea. So then they said change oil at 600 miles. Drain through the fill hole. There seems to be reputable evidence than the supplier was leaving the factory run in oil in them, which was supposed to be drained and replaced after bench test run-in.

Then they said maybe a change at 12,000 mile intervals. Good idea. And later rather than sooner they did a change and provided real drain plugs. And I understand that the newest versions have or will have vents.

In my opinion the addition of the vents will eliminate the pressure buildup, and the seal failures for the most part. Then they won't get low on lubricant, and bearing damage becomes much less likely.
BMW also lowered the fill quantity from 230ml to 180ml for exactly the reason Paul states, to reduce pressure build-up by increasing vapor space in the drive.

Topside estimates across the range seem to be about 4% failure rate, meaning 96% don't fail. I would not let the possibility deter me personally from buying any bike I otherwise wanted.
That was the failure rate in ~2002 -- it seemed to later peak ~2004 as some of the earlier bikes aged, and then dropped dramatically. I don't believe it ever got out of single digits.

I whole-heartedly agree the chances of being hit with this are very small, and would not let it deter me from buying a bike.
 
I agree that the first six items Paul listed are the main reasons for FD failures.

I see a LOT of over-loaded bikes all over the Midwest, and some of those are just carrying the rider/passenger and nothing more. Bikes have designed in load limits for a reason. Trailer towing is another load in itself.

The comments about the "sealed" FDs also make sense. If I ever replace my trusty 94 RS (still on the original FD at 164K) with the R12R, I'll mod the final drive with a vent and drain like my 94 RS.
 
I thought the slant 4's were the worst?? Not as many OF them but a higher percentage of failures.
 
I have heard estimates as high as 17% failure rate. But you have to look at mileage, also.
The maintenance specs were changed, on the R1200s at least. So BMW didn't even know the right maintenance.
The F800s also have a rear axle failure, again with high numbers based on internet world wide communication, but probably only a small percentage.
But there also, BMW did provide a new axle, an axle number superseding the previous number.
dc

front axles were replaced under warranty, with or without failure. reports of rear axle bearing failures, but not a warranty item.

(This edit is generated due to on Paul G's clarifying post #18 - "my above comment was in reference to F800GS chain driven models. I do not know about the belt driven road going models."
 
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front axles were replaced under warranty, with or without failure. reports of rear axle bearing failures, but not a warranty item.

The 2007 F800S and F800ST belt drive bikes had an insufficient rear axle tube. The belt pulley goes on one end of this tube and the wheel flange to which the wheel bolts is on the other. The metal was too soft and would deform, becoming a loose fit inside the inner races of the ball bearing and roller bearing. Once loose inside the bearing races the deformed axle tube would allow the wheel to wobble. I wrote about this in the November, 2011 issue of the BMW Owners News (ON) in my Benchwrenching column.

The 2008 and later models had a redesigned/respecified axle tube that probably is OK. If you have a 2007 and order a new axle tube the part you receive will be the new redesigned part.
 
Internet has allowed a small percentage of problems, cars ,bikes etc to be broadcast over a wide area, suddenly everyone has heard about these problems. Anew G650GS
A while ago had a front axel failure, av rider has thousands of hits reguarding that issue, if they are to be believed all G650Gs are unsafe. Somewhere BMW has the number of final drive claims made to dealers, this does not include owners who fixed their own, maybe they will part with those numbers by year and model, lawyers probably tell them no
 
Somewhere BMW has the number of final drive claims made to dealers, this does not include owners who fixed their own, maybe they will part with those numbers by year and model, lawyers probably tell them no

It's also not good for marketing, so I'm sure the folks in marketing are yelling just as loud as the lawyers.
 
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