what size bike needed?

Question
I'm planning on purchasing a bike on line to save money, taxes, clearance prices, etc... but do not know the size needed. Have not been able to find a size chart. Feel a little funny going into the a shop and asking for them to find my size. Is there a simple formula or does it require going in and having it professionally done. I am 6' with a 32" inseam. NOTE: I'm planning on purchasing an a high end bike - Trek 5200 series - does this figure into what I should do?

Thanks and appreciate the help,
Paul....

Answer
The rule of thumb I was taught is that there should be about a inch of clearance between your crotch and the top tube when straddling the top tube standing flatfooted. While today's geometry has changed, I think (for a road bike) that measurement still holds true.

Now the question is how does that translate to today's cm measurements. Unfortunately I don't know of an exact conversion chart. I would not feel embarassed about going into a shop and seeing if you can stand over a bike to check the measurement as I indicated. I'm 5'7" with a 30" inseam and ride a 52cm. So you would need something bigger then that probably 56 cm, give or take.

I would also check with the online retailer, they should be able to advise you. Another option, if you ride with a club, as your friends to test similar sized bikes to see what fits.

Hope this helps,
Scott<>