How much difference does tire size make on a bike's standover height? Specifically how much would going down from a 32 to a 28 or 25 tire subtract from a bike's standover height?

If this is a stupid question, i have full confidence that someone will tell me quickly (and insultingly) and this thread will sustain a few final jabs before sinking into the abyss. But i did search, and it is something i need to know. And any help would be…ummm…well…helpful.

Going to a smaller tire will reduce stand-over... slightly. 10mm is about all you will get dropping from a 32 to a 23. Hardly seems worth making a decision on tires based on this.

Braden is correct that the difference is small. But to answer the question - tires are sort of round. In other words, the width and height are pretty close.

Don't make a tire size decision based on standover height. The bigger (taller/wider) tire will be heavier, but hopefully able to run lower pressures, therefore more comfortable, and able to roll through the rough stuff. I pulled all the 23s off all my bikes. I run 25 on my two "fast" bikes, 28 on my touring (the biggest I could fit on the rims, btw) and 32 on my singlespeed. The 32's feel the best for bombing around town, going off-road, etc.

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.