How does one destroy a bearing in 150 miles?

Discussion in 'Cycling Equipment' started by SD2006, Sep 2, 2006.

  1. SD2006

    SD2006 New Member

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    Somehow I managed it, on my Trek 5000 with Bontrager Race Lite wheels. The rear drive side bearing broke apart internally when I was climbing up a steep hill. My LBS is now replacing the bearings for me, but I don't have a lot of faith in the new ones. Does anyone make a high quality sealed bearing that will fit my Race Lite hubs?

    Thanks...
     
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  2. ScienceIsCool

    ScienceIsCool New Member

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    Hmmm. I can think of many ways this may have happened. If there was grit inside, the bearings would chip and wear away very quickly. If there was a "weak" bearing it could have cracked or chipped and the rest of the bearings would wear away very quickly - this is uncommon but not impossible. If the bearings weren't properly installed so that there was too much play or too much side load, it could cause premature failure. If there was an uneven load from something like a bent axle, then it's possible for a bearing to crack... That's assuming it's not a problem with the bearing race. So many possibilities!

    I would just ride on the new bearings and see what happens. If they fail, then you can get new high-zoot bearings, even though that wouldn't remedy some problems such as a bent axle. Otherwise, you can chalk it up to bad luck and keep riding.

    Just my semi-informed opinions...

    John Swanson
    www.bikephysics.com
     
  3. dhk2

    dhk2 Active Member

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    From what I've heard, these hubs have a known quality issue. A buddy here with a new 5.2 this spring had his fail in first 500 miles also. He only weighs 140 lbs, but does a lot of hard climbing. In his case, believe it was the drive pawls that failed, jamming the bearings and locking the wheel.

    The LBS said it was a known issue, apologized, lent him a spare wheel while they ordered a new replacement wheel under warranty. New one has been fine so far.

    If you have any more problems, I'd ask for a new wheel under warranty. There is no reason Trek should be putting out bad wheels on their expensive bikes.
     
  4. SD2006

    SD2006 New Member

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    Drive prawls? Hmm interesting... Whatever it was it was really sudden. The wheel bearings were smooth and without slop one minute, then POW! The rear wheel was reduced to a wobbling pile of junk. I thought about getting some better bearings from Boca, but if the issue lies elsewhere I'd better fix that first...
     
  5. fish156

    fish156 New Member

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    Bearing have to be perfectly clean when packed and sealed up. If there was any contamination (i.e. a metal shaving, a piece of sand, ... - whatever) that got into the bearing it could do exactly what you describe - go from very smooth to junk in a short time. This can, and does, happen. It could have been left over from the original bearing build process or just been some tiny piece of contaminant that worked it's way into the bearing.

    Another strong possibility is that the bearings were adjusted too tight to start with. Almost every new wheel I see is too tight. Even brand new, good quality wheel sets come adjusted too tight. I adjust every single new hub bearing that passes my bench. Adjusting for QR's is not intuitive. If the bearing feels perfect before you mount the wheel to the bike with the QR, then there is a good chance it will be too tight when you clamp down the QR. A hub bearing properly adjusted for QR mounting should actually be a tiny bit loose before mounting the wheel on the bike. Overly tight bearings will fail prematurely.

    I suggest you just replace the bearing and see what happens. If you are not fully confident in how to do a proper hub bearing adjustment for QR mounting (assuming that's what you have), then get a good shop to do the adjustment for you. If you ask nicely, they'll probably be happy to show you how to do the adjustment. It only takes a minute. Good luck!
     
  6. SD2006

    SD2006 New Member

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    The bearings in my wheel hub are the sealed cartridge type, I was under the impression there is no adjustment for this type. If these can be adjusted, I'd be curious to learn more. The freehub may be a different deal, I'm not sure what's inside.

    I'd be nice if Trek could provide more specific information about the components on their bikes. It'd also be nice if Bontager would update their technical documents. Has nothing changed since 2003?



     
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