i guess i should've clarified my reason for having the question, and/or rephrased the question. i found a guy selling a Bianchi Roger in a 55cm. The standover (according to Bianchi) is 31.5—which is about .5" over what would be the top of my comfort level. i've noticed that the standover height for cross bikes is usually significantly higher than road bikes. BD attributes this to tire size for the Fantom Cross Uno. So, i was really wondering if dropping the stock 32 knobbies in favor of some 25 road tires would give me that .5" i needed. i love the Roger, and would probably ride without ceasing…but not enough to crunch my nuts on those rare occasions i had to stop pedaling and put a foot or two down.