Hybrid Bicycles - Considering a BMC UC01, wondering about frame size

A local bike shop is discounting many in-stock bikes, including a BMC Urbanchallenge UC01 flat-bar hybrid that I've had my eye on for a while. Wondering about the frame size though. I'm 5'11" and my road bike has a top-tube length of 57cm. The M-size UC01 has an effective top-tube length of 58cm, while the large is 60cm. I sat on the M and it feels fine, but I'm wondering if I should try to find a L-size frame for comparison (the shop doesn't have one).

I guess I'm asking because I've usually ridden L-size bikes, but I've read that BMC hybrid frames tend to be comparatively long. (FWIW, I've never owned a hybrid before.)

That's just 2cm. Ask them to swap the seat post to a set back if the saddle rails won't allow the saddle to move 1cm and ask them to swap the stem for 1cm longer. Fixed.

Edit. I'm confused now because your road bike is 57cm but you think you need a larger size?

Edit. I'm confused now because your road bike is 57cm but you think you need a larger size?

Forgot to say that the guy at the shop said that a flat-bar road bike should have a *longer* tt length than one's road bike (to account for the lack of drops/hoods?) and therefore the L size bike might be a better fit. Anyway, yeah, it's just 2cm, and the M size doesn't feel cramped, so maybe I'll just snag that while I can.

Forgot to say that the guy at the shop said that a flat-bar road bike should have a *longer* tt length than one's road bike (to account for the lack of drops/hoods?)

Correct. I'm 6' and normally ride a 56-58cm road bike,but my 58cm Kona Dew Deluxe is actually a touch more upright than I'd like.

If they don't have a large in stock,you might be able to get them to swap a longer stem on the medium to emulate the large and see how it feels. A 58cm hybrid sounds right for your height,but then every manufacturer uses different geo for their bikes.

Forgot to say that the guy at the shop said that a flat-bar road bike should have a *longer* tt length than one's road bike (to account for the lack of drops/hoods?) and therefore the L size bike might be a better fit. Anyway, yeah, it's just 2cm, and the M size doesn't feel cramped, so maybe I'll just snag that while I can.

Absolutely correct, hybrids tend to have about 20-25mm longer top tubes for a given frame size. Even still, hybrids tend to put you in a more upright position so you might want to go with the larger frame for more of a road bike style position (more stretched out.) The smaller frame with a longer stem will allow you to run more saddle to bar drop (lower bar for a more aero position.) With the smaller frame you might have to get a setback seatpost to get the seat back far enough.

Edit, I just looked up the geometry on that bike and it has a fairly short head tube so I'd probably go for the larger frame.

OK, I see. So a longer tt makes sense after all on a hybrid. Even so, I think I'd actually prefer a more upright position than my roadie for the constant stop/start riding on Tokyo's traffic-light infested roads. For the sake of comparison, though, I'll look for a hybrid with a 60cm tt length and similar geometry to see what that's like.

If you look at the bike on http://www.bmc-racing.com/us-en/bikes/2012/lifestyle/model/urbanchallenge%20/uc01/uc01_alfine_11.html you can see that the frame can be ordered in multiple sizes