| Author |
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Mikef5000
| | Posted on Monday, September 17, 2012 - 08:32 am: | 
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I also noticed how horrendous that rotor looks. |
Hughlysses
| | Posted on Monday, September 17, 2012 - 09:31 am: |
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Personally, based on my experience with ball bearing race failures, I don't think the bearing would seize in the first place. Normally the balls get destroyed and will eject from the race leaving just a very loose set of inner and outer races that have way too much clearance to ever seize up.
I do wonder about what looks to be heat marks on the rotor in that last picture. I'm not sure how that would have anything to do with this failure, other than the fact that it looks VERY abused.
Fortunately I've never had a catastrophic bearing failure but there have been at least a couple of rear wheel bearing failures on Ulys reported in the BB&D forum that wound up with the bearing outer race spinning inside the wheel hub, ruining the wheel. It's not the usual mode of failure, but apparently it does happen.
+1 on the blued rotor, but not sure how any kind of brake problem other than the caliper getting loose from the forks and wedging in the wheel could cause the wheel failure. |
Glitch
| | Posted on Monday, September 17, 2012 - 09:55 am: |
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Seeing this pattern in what's left of the wheel...
(quickie Gimp sketch)
is what leads me to believe it hit something hard.
Maybe there was a bearing failure that caused the bike to crash into something.
or
Maybe there was a brake failure causing the bike to crash into something.
or
Maybe we'll never know.
I still think it hit something hard, as it was sliding.
I don't think the wheel broke causing the accident, I think what we're seeing is the aftermath rather than the cause.
IMHO of course |
Natexlh1000
| | Posted on Monday, September 17, 2012 - 10:15 am: |
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You have to understand that the spokes will be bent as a result of the rim coming off too.
Perhaps a pair are bent before the crash, the cause of the crash and a second pair of spokes bent the opposite way during/after the crash? |
U4euh
| | Posted on Tuesday, September 18, 2012 - 02:44 pm: |
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Only speculation, but what if the axle wasnt completley tightned and allowed the wheel to shift in its axis causing the rotor to rub and starting the chain of events? |
Ulynut
| | Posted on Tuesday, September 18, 2012 - 04:18 pm: |
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Interesting thought U4euh. The axle pinch bolts are still in though. |
U4euh
| | Posted on Wednesday, September 19, 2012 - 01:59 am: |
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Yea I noticed those look still in tact, but I'm wondering about being seated, or tightened, completely. I agree that there is no way seized bearings done this. It would be no different than grabbing a handful of brake and locking the front wheel up. What if the races were to right/to loose, over heated, fractured and then allowed free movement against the forces of the turn, kind of like being hit in the knee from the side on a football field. Because the first thing to catch would be the pass, the bike stood up. Because the rim oscillating freely in a side to side axis the tank slap follows. Now there are forces at work on the inner axle ridges, forces on the rotor mounts, and failure. Front drops and tosses him over the top |
Mikef5000
| | Posted on Wednesday, September 19, 2012 - 07:38 am: |
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It would be no different than grabbing a handful of brake and locking the front wheel up.
It's actually 100% different from grabbing the front brake, thanks to the ZTL braking system. It would be no different from grabbing the front brake on a conventional hub-mounted brake.
Regardless, your theory sounds entirely possible to me. And I also agree simply a seized bearing couldn't have done this. It could have started the process, but that's about it. |
Sifo
| | Posted on Sunday, September 30, 2012 - 07:35 pm: |
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Any updates on this one??? |
Treefrog
| | Posted on Sunday, September 30, 2012 - 08:47 pm: |
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Negative. Last I heard the guy was conscious now. I will try to get an update. |
Treefrog
| | Posted on Monday, October 01, 2012 - 04:51 pm: |
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It's going to be a long road of recovery on this one. The fellow is awake now, but apparently has chunks of memory missing. He doesn't even remember the accident. Either the drugs have him in a haze, or the trauma is suppressing a lot of the event. He still does not fully realize what has/is happening. If you can spare a prayer, send one his way. |
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