Final drive failure resulting in crash?

Is this the first one, or have there been others that I haven't happened across?

Still waiting on all of the details, so it can't be for certain that it was the final drive...

http://www.easttnriders.com/forum/showthread.php?t=20809

Mechanically, sure, it can happen. Although there are few reported instances of this common failure resulting in a crash.

All riders of BMW motorcycles with ring/pinion rear drive need to monitor the condition of their bike and be aware of potential failure symptoms. The same goes for chain-driven bikes, but it's not as clear and easy to determine upcoming failure on the BMW final drive system.

In my personal experience, there is a noticeable progression in the final drive failure that can be felt while riding. Obviously, other factors could mask these tell-tales.

It's good that he was geared-up well.

Scetchy information, but I think you might have hit it when you mentioned the lug nuts comming off. That could make a pop, or what might sound like one.

I have never heard of a FD locking up completely and the wheel coming off. I am not sure it is even likely. The mechanical hold of the lugs, when properly tightened, would more likely cause the wheel to lock and the tire to slide. That has happened.

The only way to know for sure would be to see the FD and see if it is whole, or in chunks, and the wheel for the same information.

Glad he was fairly OK, and was dressed for the crash!

Jim

I work for a local law enforcement agency and I noticed a log entry this week that stated one of our motor officers went down after, "his ABS locked up" I am pretty sure most of our guys ride BMW's and I will try and get a hold of him and see if he knows what happened.

The rest of the log mentioned he was going approx 40 MPH at the time......not really something to look forward to.

Jett

Seems that the ABS isn't likely to "lock up", but more likely to fail to prevent a lock up. Is that what you meant, or did you mean the brakes locked all on their own.

Jim

From what I read he crashed.....with minor injuries, as a result of the "ABS locking up" be mindful alot of people who dont know what they are talking about come into play with this type of log item.

I will get further info from him when I get a chance. I have never heard of ABS locking up all on its own and it seems something else came into play.

the way it read he was cruising at 40 mph and the bike locked up.

I will be sue to post follow up.
Jett

I have a friend who was a BMW mechanic when I-ABS was first available. She had a story of a bike locking the brakes completely. If I remember correctly, she said it actually forced either the seals or the actual pistons out of a caliper.

So let me get this straight. He *might* have been riding a BMW. He *might* of had the ABS lock up (which would make it not ABS). A trained motor officer *might* not have been able to ride out a 40mph rear wheel skid and keep it on 2 wheels.

I hope you don't take this the wrong way but I find it strange that you would feel the need to report this here with so little information and zero facts. I believe in the law enforcement business they call it hearsay and speculation. Why not at least try to get a few facts before reporting it in public forum full of paranoid types that already spend too much time worrying. Perhaps since this thread is based on speculation you felt you would add in some of your own?

Not sure if it's possible for the brakes to lock. How do the pistons push themselves? Road Gremlins?? I call BS. Don't throw me to JoMama but just don't see how it would be possible.

Integral ABS has two hydraulic pumps that supply pressure to the calipers. What appear to be master cylinders are just sending pressure signals to the brain. If something were to send a spurious or corrupted signal excessive pressure could be created in the system. When doing a bleed test I recall seeing pressures of at least 1000 psi.

My thoughts exactly. ABS does not apply brakes, it releases them. Most of the time, if you get to the bottom of the issue, the driver panics when the ABS activates and they release the brakes completly thinking something is wrong. Not saying that this is the case at hand but it does happen.

Mine locked at about 65 mph when I pulled in my clutch with the first final drive failure I had. Fully loaded on a tour at about 65-75 mph my pegs began to feel funny, a weird vibration and I was trying to figure out what it could be so I pulled in my clutch to coast for a moment to see it would stop the vibration, that could mean the "problem" was forward of the tranny. Well, when I did that the rear wheel locked so I dumped the clutch and the rear wheel started turning again. At that point the noise from the rear drive was horrific and I got her stopped asap.

So which is it? BS or ABS?

By the way, my thoughts exactly. The guy describes unknown lockup. Which could happen, of course - for example, as other inmates mentioned, by lugnuts coming off.

I just don't see how brakes would do it, even if he had a machine with brake assist.

Let's wait for details.

What bike were you riding? What specifically failed?

Goodness, this is a thread to cherish.

Remind me never to get caught in a suddenly stopped high rise elevator with you guys!

01' 1150 GS, large main bearing in the FD went south.

I had both the FD fail and the rear wheel almost fall off my 2002 1150 GSA. the FD failed about a 2 hours after i started feeling unusual vibrations in the foot pegs. It was the big bearing that failed. i was in the desert of Peru at the time and had to limp back to Lima ( at around 20-30 mph) for repairs, the wheel never locked but it felt very loose.

The rear wheel almost fell off about 1,000 miles or so after i replaced the FD. the vibration was very similiar as when the FD drive failed and i thought the bearing had gone again, but when a checked the lug studs, all were very loose and ready to fall out. I had used a torgue wrench ( granted a cheapo one)on the studs when i put the wheel on after replacing the FD. needless to say i check the studs very often and they have not loosened at all so i dunno what happend.

I may have the oldest, first generation, oil head final drive failure.
1995 BMW R1100RSL 90,000 miles:
About 03/04 I was 'racing' my nephew up the mountain to reach the Continental Divide, Colrado. Bike had been running perfect, but on reflection I did feel a slight 'hiccup' now and again, like it popped out of drive for a nano second, this had happened a few times that year. Any way, I was doing about ninety, pulling up the hill and taking curves 'on power', it was really nice. Sean, my nephew was right behind me, trying to keep up on his dads BMW R100GSPD, and doing a stellar job too! All of a sudden, without any warning, the bike just kinda dragged in the rear and slowed from ninety to twenty in a second or two, the wheel didn't lock or skid. I managed to pull over to the side of the mountain, I was perhaps half a mile from the summit. I was still on the road, but over to the right, I got off the bike as it wouldn't move. I couldn't push it on my own, the rear was 'kinda' locked, but not completely. Sean by now had doubled back and he helped me push, the rear end went clang, clang, clang as we moved it, got worse and worse, until we had to skid push it in the dirt to a safe place. When the tow truck came we had to skid it on the flat bed. Nothing was smashed, no oil leaks showing, but the rear was locked. That's all folks, I parked the bike at BMW of Colorado Springs on Sunday night, borrowed a truck from my brother in law, and went to Sturgis! I phoned the dealer on Tuesday to tell them to drag my bike in and check it out. NO BIKE! I guess someone stole it from the lot! I got $4500 off the insurance company, added some and bought a 2000 BMW R1150GS. Worst part was riding bitch on my wife Colleen's bike from Castle Rock, Colorado to Los Angeles, California! I've beat the GS to heck and back, 50,000 miles and no trouble, just changed the rear drive oil about every 10,000 (or more). I ride it pretty hard in to corners, changing down and engine braking, it has held up fine, so far. I'm worried though, if it locks and pitches me I guess I'm fucked.

A good tradesman never blames his tools BTW your web site is broken as well.

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