Overtightened bearing housing=Problems??

Discussion in 'rec.sport.unicycling' started by silverfridge, Mar 29, 2006.

  1. silverfridge

    silverfridge Guest

    when i last change my tire, i was doing it in bad light, and because i
    couldn't feel any resistance, i overtightened the bolts holding the
    wheel to the frame,
    u know the ones, that tighten that U shaped bit of metal over the
    bearings and connects to the frame>

    anyway, that was a while ago, and now i notice that the U shaped bits
    of metal are a bit bent,and the screws holding the frame and the U
    together are bent, but the frame part where the screws fit in is okay.
    could this cause problems later on?
    My uni is a Qu-ax 24" Muni, and i ordered it from NZ i live in WA

    also, i broke a bolt in my seat, one of the bolts that tighten the
    saddle to the post, and now i have threee, how can i go about fixing
    this, and will this be a big prob either?

    cheers, and yes, i think i do have a slight overtightening tendency,
    but thanks a lot for any help u could give, in advance


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  2. icon

    icon Guest

    Wot, no replies?

    I suppose it goes without saying that if you've overtightened the bolts
    to the extent that you've bent the lower bearing housing you've got
    problems now, not later.

    The rather odd design of the bearing housings on unis invites
    overtightening, which pinches the bearings into a slightly oval shape.
    Since the inner bearing is constrained to be round by the shaft it's
    on, the bearing will be stiff and wear out quicker, as the balls have
    to squeeze through a smaller gap than they're designed for.

    I don't think there's any merit, with nyloc nuts on bearing housings,
    in tightening much beyond finger-tight.

    No doubt Qu-ax can provide a couple of replacement bearing housings and
    some bolts.

    When I get around to making a uni[1], it'll all be much better designed
    - properly machined bearing housings that extend the full circumference
    of the bearing, less a couple of thou.


    [1] Ha!

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  3. Jim

    Jim Guest

    you can get replacement bearing holders from 'unicycle.com NZ'
    (http://tinyurl.com/de27z) (i couldn't find any on Unicycle.com
    Australia's site). these come with replacement bolts (but these might
    not be long enough to fit 42mm bolts).

    Replacing a bolt on a saddle can be a pain to fix if you don't have a
    Fusion style saddle with removable cover, but it can be done. You have
    to strip the saddle down replace the bolt and build it back up again.


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  4. flyer

    flyer Guest

    icon wrote:
    > When I get around to making a uni[1], it'll all be much better designed
    > - properly machined bearing housings that extend the full circumference
    > of the bearing, less a couple of thou.
    > Regards
    > John
    > [1] Ha!

    The 'KH' (http://www.krisholm.com) has this. Works really well. I
    usually keep the bolts on my non-awesome bearing holders to a light
    push on the end of a wrench that's screwing them on. Haven't had any
    problems (too loose nor too tight) yet.

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  5. skicker

    skicker Guest

    I had the same problem on my qu-ax muni, the bearing holders and bolts
    that came with it seemed to bend quite easily. Got some new ones from
    unicycle.com and that sorted it, plus they seem a bit more sturdy.

    I did try to find some kind of tube which i could put round the bolts
    in the gaps between the holders, but never found anything suitable. The
    idea was to keep the gap even either side and add a bit of support to
    stop the bottom bit bending.

    I agree that the ones on the KH frames are much nicer and wrap right
    round the bearing, solving this problem.

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