frame size

andy610

what will the difference be if i change from a 56cm frame to a 54 frame

redddraggon

At 5'6" (am I right?) I think you'd be better off with a (standardish sizing) 52cm frame.

Generally all the tubes get shorter as you get to a smaller size - the most important (IMO) tubes being the top tube and the head tube.

All the manufacturers have geometry tables on their sites to tell you the differences between frames.

If you don't know what size you need, go to a "bike fitter" who should you out properly. I think a "bike fitter" has been recommended to you a good few times.

Juju_uk_68

Red's right - that manufacturers will raise and lower bottom bracket heights through arange to acocomodate ever expanding seat tube heights, so standover height doesnt always raise itself in a linear way with the stated measurement.

What does increase as frame sizes increase, is the top tubelength, ie your reach, and the head tube, ie where the bars/stem place themselves in relationship to the ideal saddle height.

Of you have short arms/short top body in relation to legs, then at 5'8 you could concievably be a 50cm frame is say a Bianchi c2c range, (I am 5'7 with this build) but I guess the median build would be 53, and if you have a tall top body to legs, even a 55 to get the arm length to hoods right. The legs sort of "look after them selves" woth saddle height adjustment and lower bottom brackets.

Unless you actually have to rest you knackers on the top tube, dont worry about this height, and given saddle hegiht adjustment of several inches, its arguable that you can usually adjust the bike for the bottom half of the body easy enough, but its the top body measurements that are more static, and this is where fit is important.