I'm 5'11" with the same 30/31" inseam as you. On vintage bikes with traditional geometry, I ride 56/58cm frames. Because I have a long torso and short legs, the 56cm is a good height but needs a longish stem. The 58cm is a touch on the tall side, but the top tube is a better fit.
In either case, a 52/53cm bike would be too small for me, and likely be too small for you. I wouldn't buy one that size without trying it out for fit.
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Last edited by bigbossman; 11-28-06 at 11:48 AM.