How to determine frame size

zeroseven

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.

father_jack

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.

zeroseven

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

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

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

StillGoing

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.

Lillywhite

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

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.