Front Wheel Flat Spot

japsy
japsy Posts: 78
edited January 2010 in Workshop
Hit a mahoosive pothole last night but managed to somehow not punture but has deformed the rim somewhat (rim walls also look ok), there is a slight flatspot, only noticeable when braking (brake pads juddering at the flatspot) and can't feel it when rolling. Continued on spin for another 20 miles. The spoke is lose, I suppose all I need to do is tighten it up. Anything else I need to check to ensure this wheel is ok?

Thanks.

Comments

  • Chris James
    Chris James Posts: 1,040
    Have you just put a dent in it radially? If so, and if the resulting out of shape wheel isn't too annoying then just ride it.

    I would check other spoke tension too, also bear in mind that tightening your one loose spoke could pull the wheel laterally out of true.

    I did exactly the same last spring, trued up the wheel myslef trying to equalise spoke tension as best as posssible, and have been riding the same wheel since then. I do check the spoke tension around that area regularly though as the same spoke has a tendency to loosen off again. On very smoooth roads I can feel the flat spot, but otherwise it is fine.

    Your LBS will probably have a tool which will be able to pull the rim back into shape if it isn't too bad.
  • japsy
    japsy Posts: 78
    Chris James wrote:
    Have you just put a dent in it radially? If so, and if the resulting out of shape wheel isn't too annoying then just ride it.

    I would check other spoke tension too, also bear in mind that tightening your one loose spoke could pull the wheel laterally out of true.

    I did exactly the same last spring, trued up the wheel myslef trying to equalise spoke tension as best as posssible, and have been riding the same wheel since then. I do check the spoke tension around that area regularly though as the same spoke has a tendency to loosen off again. On very smoooth roads I can feel the flat spot, but otherwise it is fine.

    Your LBS will probably have a tool which will be able to pull the rim back into shape if it isn't too bad.
    Thanks for the reply, yes it is just radially at the moment. I will just fix up the tension and keep riding it.

    This is the 3rd wheel I have damaged this winter, the other two have bent sidewalls so I consider myself lucky this time. The dangers of chainganging at night....
  • Monty Dog
    Monty Dog Posts: 20,614
    Depends on where the flat spot is - if localised between two spokes, then you can't really do anything and trying to manipulate the rim otherwise could weaken it. Tighten the spokes to even the tension and learn to avoid potholes! FWIW the British Standard for new bikes is 5mm tolerance in radial true and in most cases is barely imperceptable.
    Make mine an Italian, with Campagnolo on the side..
  • John.T
    John.T Posts: 3,698
    British Standard for new bikes is 5mm tolerance in radial true and in most cases is barely imperceptable.
    Could this be 0.5mm by any chance.
    To the OP. If you can feel it on the brakes you have damaged the side wall. You may be able to ease it back in a vice, very gently.
    My Fleet.
  • japsy
    japsy Posts: 78
    John.T wrote:
    British Standard for new bikes is 5mm tolerance in radial true and in most cases is barely imperceptable.
    Could this be 0.5mm by any chance.
    To the OP. If you can feel it on the brakes you have damaged the side wall. You may be able to ease it back in a vice, very gently.

    The reason I don't think the sidewalls are damaged is because there isn't any deflection in the walls - the pads are near end of life and overlap ever so slightly the inner of the rim and because of the flatspot this rubs.
  • John.T
    John.T Posts: 3,698
    Fair enough. Just re-tension the spokes.
    My Fleet.

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