Wheel is doing my head in.

Discussion in 'Bicycle Mechanics and Repairs' started by iAmiAdam, 17 May 2010.

  1. When to get some new tyres on sunday, 26 inch 1 3/8 road tyres, went to fit them, and they didn't god knows how we got it on, but the people at halfords had to cut it off. this baffles me because the tyre that came off is a 26 x 1 1/4, so in theory I had an 8th of an inch to play with. Now I'm no mathmetician but this doesn't make sense to me. The bike is from the 70's so the only possible explanation is the tyre sizing has changed maybe?

    Any ideas?
     
  2. brokenbetty

    brokenbetty Über Member

    Location:
    London
    Welcome to the wonderful world of tyre sizing!

    http://www.sheldonbrown.com/tire-sizing.html

    It makes more sense when you look at the ISO size - the big number is the diameter

    26 1 1/4 = 597mm diameter
    26 1 3/8 = 590mm diameter

    (modern 26" mtb is 559mm)

    so your new tyre was 7mm diameter too small for your rim. It's not surprising it didn't fit, though it's quite surprising you got it on in the first place!
     
  3. OP
    OP
    iAmiAdam

    iAmiAdam New Member

    Right, it makes sense now, that website didn't to me really.

    Yh, We nearly buckled the rim doing it, but somehow we did.
     
  4. hubgearfreak

    hubgearfreak Über Member

    i'm impressed. you should go in for the old ripping up phone books party trick
     
  5. OP
    OP
    iAmiAdam

    iAmiAdam New Member

    Got the jersey for that already.
     
  6. OP
    OP
    iAmiAdam

    iAmiAdam New Member

  7. brokenbetty

    brokenbetty Über Member

    Location:
    London
    Yes those tyres will fit.
     
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