rear wheel 'bumping'

mmuk
mmuk Posts: 398
edited February 2009 in Workshop
I was out today - punctured, repaired and managed to get about 6 bars in the tyre with the hand pump. After 10 miles or so, i started to notice a 'bump' - like the wheel was mishapen. I stopped, checked the spokes - all were fine - and continued on my way. The bump got progressively worse - it's a bit like riding over a rutted road - the wheel 'looks' circular and I am at a loss to know what to do - could it be something to do with the lower pressure? I haven't had a chance to pump it to the normal 9 bars and go out again - and I'm a bit worried whether I should!

Any thoughts?

(the wheel are hand built about 6 months old, a few 00 miles in them only)

thanks

Mike

Comments

  • redvee
    redvee Posts: 11,922
    Sounds like the tyre not seated on the rim correctly, deflate the tube and push the valve into the tyre and give it some air.
    I've added a signature to prove it is still possible.
  • edhornby
    edhornby Posts: 1,780
    have you checked that the tyre is on straight and even ?? if it's not bedded on the rim evenly it will feel bumpy

    get the bike on the workstand, or stick it upside down and spin the wheel. attach a pencil to the fork or chainstay wwith some tape and use it as a marker to see it the wheel is buckled, as the rim will waver in and out towards the pencil - also do this with the tyre

    if there's no obvious buckle, take the wheel off, and remove the tyre and tube, check for foreign objects and rebuild. put a bit of air in the tyre, check it's all even and get it up to running pressure

    hope one of these things works
    "I get paid to make other people suffer on my wheel, how good is that"
    --Jens Voight
  • thetrotter
    thetrotter Posts: 258
    redvee wrote:
    Sounds like the tyre not seated on the rim correctly, deflate the tube and push the valve into the tyre and give it some air.

    +1. Has happened to me before. Lucky you only put 6 bars in it 8)
  • cougie
    cougie Posts: 22,512
    Yeah deflate it, wiggle the tyre and play with the valve and it should sort itself out I reckon.
  • GeorgeShaw
    GeorgeShaw Posts: 764
    I was always taught, when inflating a tyre, to part inflate it. Then push the valve in (if it won't go, then it's over-inflated), then go around the tyre pinching it away from the rim - on both sides - to make sure that it's seated properly. You can make a visual check as well - there's usually a mould mark around the side of the tyre that can be used to gauge it. And also bounce the tyre at several points to help it seat. Finally fully inflate. Sounds like overkill but has never failed for me.

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