How to determine frame size

zeroseven
zeroseven Posts: 347
edited October 2010 in Road beginners
I'm sure there are endless threads on this, but I cant find them. Occasional MTB rider (20" frame) that is toying with the idea of an road bike, Maybe Spesh Allez comp.... but how do I determine frame size? Guilty of wanting to buy S/H so not easy to go to LBS and get sized properly, any advice gratefully received.

Comments

  • father_jack
    father_jack Posts: 3,509
    no idea since you haven't given your height. But if you're riding a 20" hard tail I (guess) looking at 56cm or bigger.
    Say... That's a nice bike..
    Trax T700 with Lew Racing Pro VT-1 ;-)
  • zeroseven
    zeroseven Posts: 347
    Thanks for the reply FJ, I was actually asking about the methodology rather than a specific recommendation.... but I'm 6 foot, 34" leg, 13 stone

    I ride a FS, Specialized 2006 Stumpjumper.
  • zeroseven
    zeroseven Posts: 347
    Thanks for the reply FJ, I was actually asking about the methodology rather than a specific recommendation.... but I'm 6 foot, 34" leg, 13 stone

    I ride a FS, Specialized 2006 Stumpjumper.
  • father_jack
    father_jack Posts: 3,509
    You really can't compare the two, but have a play with Canyon's bike fit. Don't rely on that though.

    http://www.canyon.com/_en/tools/pps.html
    Say... That's a nice bike..
    Trax T700 with Lew Racing Pro VT-1 ;-)
  • StillGoing
    StillGoing Posts: 5,211
    They're all different. What might be 56 in one manufacturer could be something completely different in another. I've found it is easier to deal with the manufacturer or a good dealership for advise on frame size for a specific make. I've lost out on a couple of cheap clearance bikes' a Willier Izoard and an EMX-3 because the manufacturer informed me the bike I was looking at was too big. The shop might have convinced me otherwise.
    I ride a bike. Doesn't make me green or a tree hugger. I drive a car too.
  • Lillywhite
    Lillywhite Posts: 742
    It is now impossible to compare sizing between different manufacturers as has been pointed out many times on this forum.

    Top tube length is just as important as seat tube length.

    The only sure way to find out if a particular bike fits you is to try it out.

    Failing that, go to a good bike shop that provides a frame fit service, take advice and see what they can provide for you.
  • morrisje
    morrisje Posts: 507
    The most important measurements are horizontal top tube length and head tube.

    The horizontal top tube for someone of 6' will be 56cm or 58cm
    The headtube length dictates your position, i.e. short headtube equals racy position and a longer one gives you a more upright position. Usual headtube length for someone of 6' will be approx 16cm.

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