A few years ago you could easily match frame sized from one manufacturer to another ie a 54 cm frame from one manufacturer was the same as a 54cm from another and frame sizes were always measured centre of bottom bracket to centre of top tube and all top tubes were horizontal.
Since the arrival of compact (sloping top tube) frame geometry that has changed, different manufacturers quote frame sizes very differently. As this gives more scope to adjust the saddle height more important now is the top tube length of the bike. Hence if you tell us your current frame size please let us know what manufacturer it is and also your height.
Below we give you a guide to the frame sizes we have on our rental fleet.
Dolan Bikes – We have all sizes in our Dolan Road Models
Dolan Size Actual BB to top seatpost Horizontal top tube Recommended Recommended
S 44 53 5' to 5'7 1m52 to 1m70
M 48 54.5 5'7 to 5'10 1m70 to 1m78
L 52 56 5'10 to 6' 1m78 to 1m83
XL 56 59 6' to 6'5 1m83 to 1m96