Fixed gear frame size ?

Without looking at the frame and actually taking measurements it is impossible to tell for sure. But taking a stab both the 56 cm trek and a "usual" 54cm are considered to be "medium" so that puts you in the ballpark. With the information provided that's the best anyone will be able to say.

This is the bike I'm looking to get. They don't give any of the geometry. I guess if the fit guy at my shop suggested the 54cm over the 58cm, that's probably what i should get. If the frame is a tad small, i can always buy a longer stem. I am 6'1 if that helps.

http://www.roadbikeoutlet.com/single-speed-fixed-gear-fixie-bicyles/gavin-fisso-singlespeed-fixed-gear-bike.html

Well going by the suggested sizing chart on the provided website, 6'1" matches with the 58cm. But again, this is just a stab in the dark. You might have very short legs for your height or some other peculiarity which makes another size more suitable. No-one can tell unless they're in the same room as you and the bike at the same time.

The person you really need to be having this conversation with is the guy who suggested the size in the first place. After all, he's the one who probably fitted you to your Trek, and he should be able to explain to you the reasons why he specified a particular size (since he can see you and the rest of us cannot).

Without him, the only reasonable way you can compare the two bikes is by comparing the geometry. Sizes are just numbers and often don't even relate any particular dimension of the bike.

Quoted post said:

Originally Posted by hippie [IMG]/img/forum/go_quote.gif[/IMG]

I looking to get a fixed gear bike, but the one i want only offers 3 frame sizes. They offer a 50cm small frame, a 54cm medium frame & a large 58cm Frame. My Madone 6.9 is a 56 cm & fits me perfectly. So which frame would be a better fit for me the 54cm or the 58cm ?. The fit specialist at my local Trek store sayed he would rather see me get the 54cm over the 58cm. What are some educated opinions ?.

What's the top tube length of the Trek? Get the frame that most closely matches that. 'Size' as measured by seat tube length varies wildly maker to maker in terms of seat tube ANGLE and top tube LENGTH...the two measurements that mean something.