Interesting fit ranges

Looking at some of the posts in response to Gerard’s survey really surprised me regarding the range of sizes the people of relatively the same height ride. For example, I am riding on a 56cm Cannondale and am 6 feet tall. I know people around the same height as I am riding 54cm Cervelos and I noticed that someone who is 6’1" indicated that they ride a 61cm frame. Is there that much of a difference in the way frame sizes are labelled/identified or is this a sign that many of us are on the wrong size frame? I know that when I first started doing tris the bike that I bought was a 58cm Centurian Ironman expert and it was a 58cm (they had it on sale and it seemed to fit ok and the guy at the local bike shop told me that it fit so I bought it) and it feels huge compared to my Cannondale, which I’ve been riding for years and seems to fit me very well.

I think that part of this is that different bike companies measure their sizing in different ways. Ie. c to c measurement, c to t measurement, compact bike measurements. etc.

the sceond aprt of the equation is that there is a natural range of sizes + or - 1 or 2 cm. whiich you could theoretically get fot on…

the last piece is not all of these people may be on the correct size bike.

Allan, although your top tube is probably a 56cm on your road frame, knowing you ride on a forward seat post, I’ll bet your top tube is aproximately 51 to 53cm CtoC, if you were to measure your seat tube straight up from the BB to center of your seat pin. I know Cannondale, at one time sold there Tri frame by this top tube measurement, as well as Cervelo.

I just measured it and it is 55. I pulled out the old specs for the frame and they list the top tube as 56.5. I’ve just been reading through dan’s article on sizing which clarifies how there can be so much variation in the sizes.