rear tire repeatedly thrown from rim

Discussion in 'General Questions' started by joerio, Mar 19, 2010.

  1. joerio

    joerio New Member

    the sprocket is totally parallel with the rear rim, a wobble is still present at top speed right before the tire comes off. this has happened three times now. can some one please help? any advice would be appreciated. this is my first build and it went like clockwork, except for this.

  2. Wheres my dog

    Wheres my dog New Member

    Are you saying the the actual rubber tire is coming off of the rim at high speeds?

    What psi are you running in your tires... 40psi, 50psi, etc?
  3. AussieSteve

    AussieSteve Active Member

    The sprocket should have nothing to do with the tyre rolling off, if it's fairly true. It sounds like a tyre pressure issue to me, too.
    I can't run less than 40psi in the front and 50psi in the rear or I have problems with pinch flats and once, like you, the tyre rolled right off the rear rim when I hit a hard bump while turning, with 30psi.
    If pressure isn't the problem and the rim is OK, throw that tyre away.
    (Tire is tyre in Oz)

    An afterthought - does the wheel lock up just before the tyre is thrown off?
    You might have other chain issues, causing the chain to jam and lock the wheel. Then, if your tyre pressure was too low...
    Last edited: Mar 19, 2010
  4. motorpsycho

    motorpsycho Active Member

    It's possible that you have the wrong inner tube in the tire. the wrong inner tube woudl allow too much room between the tire and the rim. as speed increases your tires will "grow" taller. if the inner tube is too small it will not help hold the tire to the rim, that could be why it's coming off. or the bead of the tire is too worn and it is not seating into the rim far enough. again, at high speeds the tires grow taller and stretch a little.
    I don;t think a chain issue is the problem, unless your chain is binding and causing the rear wheel to lock up.
    But really, if the tire is coming off the rim, i would get a new tire and a new inner tube...i think it's a tire/inner tube /rim issue myself.
    with the correct inner tube, air pressure and a tire with a good bead, it would be VERY difficult for the tire to come off the rim. i have never heard of this happening before.
    or, possibly the rim where the bead of the tire goes is messed up? not allowing the bead of the tire to stay seated? i don't know, i'm baffled on this one.
    Last edited: Mar 19, 2010
  5. JDS

    JDS New Member

    What kind of rim is it? Steel or Aluminum? Spin the rim and watch the walls of the rim. I have seen rims that have hit hard bumps flare out a little, when this happens it is easy for a bead to slip out, especially at high speeds. If it is steel you can probably push a dent back in, if aluminum you are probably out of luck. I would check that and if that doesn't seem to be a problem it could be a tire size problem. I guess if you told me what the bike is and what the tire is I could help further.