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  1. #1
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    Fork and frame issues, need assistance diagnosing please.

    Hello all, I've enjoyed reading the forums for a while now. Finally decided to join now I have this puzzling issue with a bike. Its a Trek Mountain Track 800, its a tiny 13.5 inch frame, I got it for my 8 year old son to use. The problem I'm having with it is the handlebars/fork wobbles slightly in the frame. It is the kind of wobble that when you first notice, you think its just a slightly loose wheel, but its not. It does not interfere with his riding experience as when any amount of weight is on it its not noticeable. But I'm concerned with it wearing down more and what I can do to get it back into good shape. What parts on the frame can I replace to improve this? Would replacing a stem help this? Fork? The whole frame? Or just the bearings or some other small piece near the stems mounting? I haven't yet disassembled the stem since, in the condition it is in, I want to have a game plan if I disassemble it, no exploratory surgery.

    Any help is greatly appreciated, thanks.

  2. #2
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    Sounds like the headset is loose.

  3. #3
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    Yes, I tighten the headset and it stops, but very soon thereafter headset just gets loose again.

  4. #4
    rebmem rbtm
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    Post a photo showing the head tube and stem.

  5. #5
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    Quote Originally Posted by cobba View Post
    Post a photo showing the head tube and stem.
    Here it is. The guy I bought it from clearly took some pliers to it and beat it up. I use a crescent wrench when needed and it still grabs it fine. Do you guys suspect I could replace the headset, will that fix the problem? Will any MTB 1 1/8" headset work?
    Attached Thumbnails Attached Thumbnails Fork and frame issues, need assistance diagnosing please.-20130530_023047x2.jpg  


  6. #6
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    Is that a steering damper mixed in there?

  7. #7
    It's about showing up.
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    Blue-sky guess...this has long been a problem poorly addressed and made worse by bad/infrequent maintenance; whence the manhandling of the adjusting nut. Attempts to manage this have Left the headset badly worn and it will no hold its adjustment long. I bet the innerds are all messed up. You may have to replace it. Note that you have an older style quill headset.
    I don't rattle.

  8. #8
    nothing to see here
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    Quote Originally Posted by Orajel View Post
    Here it is. The guy I bought it from clearly took some pliers to it and beat it up. I use a crescent wrench when needed and it still grabs it fine. Do you guys suspect I could replace the headset, will that fix the problem? Will any MTB 1 1/8" headset work?
    The first thing I would do is remove the quill stem/bars, then undo that mangled nut, remove the brake cable support plate and see if there's another nut below it. If there is, tighten that (lifting and supporting the bike from below the fork crown will help the headset seat properly), then reassemble. You may want to put some locktite on the top nut before you tighten it. Don't overtighten it as this will damage the bearings and cups.

    If you wanted to go a step further, once you've removed the stem and nuts holding the steerer, you'll be able to access the bearings, which are probably loose fitting. Remove top and bottom bearings (don't lose them), clean and re-grease before reassembling.

    Failing that, you'll need to replace the headset with a similar threaded style that matches your head tube size.
    I see hills.

    I want to climb them.

  9. #9
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    Yeah, there should be a preload nut and a lock nut. Tightening the lock nut (top) without tightening the preload nut won't work very well.

    Also totally possible the whole thing is shot and needs to be replaced. A 1 1/8" threaded headset will work (provided it's not 1")

  10. #10
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    Thanks for all the feedback. I went ahead and just purchased another headset for the thing, and ti is a 1 inch threaded. I purchased the bike like this used, I wasn't the slob who tore it up I swear! haha Used 13.5" frames are hard to find around here, I can't be too picky. I was just concerned it may be an issue beyond the headset perhaps shared symptom with fork/stem. But with a bit more research and your guys feedback I'm confident this is a symptom isolated to the headset. Considering the condition of the lock-nut I'm not going to repair only replace. Will update with my progress, thanks guys.

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