I recently got the Kilo tt stipper, and using the competitive cyclist "eddy fit", I determined that I should get the 55cm. BTW, I'm 5'11" (don't remember my inseam measurement). Anyway, going with my measurements, it looked like the standover on the 55cm would be a little "tight" with the eddy fit, but the top tube about perfect. I took the plunge on the 55cm and am glad I did. Standover isn't bad with shoes on, and I can always lean the bike a little when straddling the top tube. Thing is, if I had gone a size down, the handle bars would have been way too low for me (with respect to saddle height). I prioritzed top tube length over standover clearance and I'm glad I did.