V confused Fulcrum 1 front wheel size different from back

MrZ Posts: 55
edited April 2010 in Road buying advice
This may be daft question but google hasnt unearthed anything so i'll ask away...

Bought some fulcrum racing 1 wheels a couple of months ago in the sales and as the weather and roads have been rubbish i've only just got round to getting them out and installed with tubes and tyres.

Only problem is the Conti GP 700 X 24'S I've bought fit onto the back wheel as expected but the tubes and tyres are way too big for the front wheel. The front has 622 diameter printed on it the same as the back but appears to be a much smaller wheel...????

Am i missing something obvious here or is something amiss?

thanks in advance for any help/advice


  • Lillywhite
    Lillywhite Posts: 742
    MrZ wrote:
    . The front has 622 diameter printed on it the same as the back but appears to be a much smaller wheel...????

    622 rated tyres should fit a 700 diameter wheel.
  • andy_wrx
    andy_wrx Posts: 3,396
    622 is the same as 700

    622 is the diameter of the internal tyre bead on the rim, whereas 700 is the notional diameter of the wheel+tyre - obviously notional as it'll depend on what tyre you have fitted, whether it's 23/25/21/28/35/etc.

    What we tend to call 700 x 23 tyres are really 622/23 - your Conti's probably have both 700 and 622 moulded onto them, yes ?

    If both wheels are 622, then the same tyre should fit on both.
  • keef66
    keef66 Posts: 13,123
    But he says they don't!

    How jolly strange.
  • gsk82
    gsk82 Posts: 3,521
    my gp4000s fit my racing 1s fine :D
    "Unfortunately these days a lot of people don’t understand the real quality of a bike" Ernesto Colnago
  • Simon Notley
    Simon Notley Posts: 1,263
    This calls for a photo! Preferably next to a measuring tape.
  • andy_wrx
    andy_wrx Posts: 3,396
    edited April 2010
    keef66 wrote:
    But he says they don't!

    How jolly strange.

    Yeah, I know he says they don't - I'm saying they should 8)

    What other sizes could they be ?
    - it could possibly be a 650 wheel rather than a 700, but it would look totally different in size, stood next to one another, and he says both have 622 on anyway (i.e. are 700C - a 650 wheel would say 571 I think http://www.sheldonbrown.com/tire-sizing.html)

    Dunno about F1's, but I know Ksyriums have a different height (depth/profile if you prefer) rim front and back, but they're the same size as far as the tyre is concerned

    And I've seen some MTB's with different width rims front and back so you can run a fat tyre on the front for grip and a thin tyre on the back for traction, but can't see this on a roadbike

    It's nothing silly like there's rimtape on one and not the other ?
    (IIRC F1's don't use rimtape anyway...)
  • hopper1
    hopper1 Posts: 4,389
    Any chance your front wheel could be a 650c?.... :oops:

    I don't know if Fulcrum do 650's, but just a thought.
    Start with a budget, finish with a mortgage!
  • MrZ
    MrZ Posts: 55
    Thanks for the replies everyone, i too thought it may be 1 650 front wheel by accident (bought off ebay so was doubly paranoid), but couldnt find any evidence of Fulcrum selling one.

    However, must apologise as today its all sorted....

    The tyres fit fine today , no idea what went on in my head last night!
    Can only blame it on a frazzled brain from working and training too hard and a bottle of red wine......Sorry!
  • hopper1
    hopper1 Posts: 4,389
    Well, at least you had the balls to come back and say it's now ok. :wink:
    Glad it worked out.
    Easy on the wine, next time you're going to mess with your bike!
    Start with a budget, finish with a mortgage!
  • acidstrato
    acidstrato Posts: 945
    GP4000s on my racing 1s

    was abit of a tight squeeze tho iirc
    Crafted in Italy apparantly