Quote Originally Posted by SadieKate
Remember that the numbers a manufactuer puts on its website are not necessarily obtained the same way from manufacturer to manufacturer. Each can measure from a different spot on the frame. If you have the frames available, it is best to take your own tape measure and measure each one. In other words, not all 48s are not equal even from the same company.

This is SO true! My 54 Colnago was a little too small, so we went to a 55 for my Merckx. Well, the Merckx measures at a different place on the tube, and it is slightly too big! We futzed with it and it works, but ideally should be one notch smaller.