This is why I have never bought a frame online, "ride the bike" is best answer to any question about how something will fit. But I am exploring online purchasing. Here are some real numbers.
Frame A (Current ride):57.5cm TT with 73.5 HT angle and 73 degree ST angle. ST is 58
Frame B (potential online purchase): 58.1cm ST with 71.7 HT angle and 72.7 ST angle. ST is unknown but claimed frame size is 59 so perhaps ST is 59 (cant really assume that however)
Lets just say for sake of simplicity that the .3 degree difference in ST angle is unimportant and all other things are equal (which they are not but both do have 17.5cm HT). Using FBINY formulas
Frame A: 57.5 x .2840 = 16.33CM
Frame B: 58.1x .3134 = 18.2CM
What have I just learned about reach on each bike ( if anything)?
I am concluding that Frame B, with same 110mm Stem I have on Frame A, will have me more upright than Frame A (which is what I am looking for since this will be used for commuting vice the hammering I do on the other bike on weekend rides).
Last edited by DOS; 11-11-10 at 11:38 AM.