700c wheels...

Discussion in 'Bicycle Mechanics and Repairs' started by Maz, 13 Dec 2007.

  1. Maz

    Maz Legendary Member

    Does the 700 mean 700mm in diameter? Is this a standard size wheel on a road bike?

    Thank you in advance.
  2. Smokin Joe

    Smokin Joe Legendary Member

    The diameter of a 700c wheel is actually 622mm. I think the 700 refers to the approximate diameter when a tyre is fitted, and it is the standard size roadbike wheel.
  3. TheDoctor

    TheDoctor Resistance is futile! Moderator

    Bang on.

    There used to be 700A and 700B - I think the letter related to the width of the rim.
  4. OP

    Maz Legendary Member

    Thank you very much.
  5. I agree you're right, it just doesn't make a lot of sense, not today at any rate

    622 is the wheel diameter (to the tyre bead seat, not rim-to-rim), so a 700 wheel including tyre would need a tyre (700 - 622) = 78, /2 as it's twice the tyre 'height' => 39

    So it would be a '700' wheel with a 39mm tyre.

    Perhaps that was a standard tyre size in 1910 or whenever they invented this system, but today we're all running racers round on 700/23 (= 688) or tourers on 700/28 or 32 (= 678 or 686)
  6. HJ

    HJ Cycling in Scotland

    Auld Reekie
    For a fuller explanation there is alway Sheldon Brown, although it maybe more that you really want to know.
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