54 vs 52 help
 

Hey guys I have a 52 specialized tricross and looking to swop out my f/f to specialized roubaix. I found one I really like but it's in a 54. The stand over height is actually slightly lower on the 54. 776mm on the 54 and 780mm on 52. Is there any measurement that is critical or could I possibly get away with getting the 54? I'm about 5ft 8

stand over?

If you can stand over it comfortably and can easily reach the bars without a ridiculously short stem, then I'd say the 54 fits.

I'm 5' 8.5" tall and I ride a 54cm Roubiax. Best fitting bike I've ever had.
I also just sold a 54cm Tricross Sport. The Tricross had a shorter effective top tube length and a more upright riding position than the Roubaix but I think you'd fit fine. You may need to make an small adjustment to stem length to get it perfect.

I' 5'8" and ride a 54. I'm comfortable on a 56, but wouldn't go smaller than 54.