Originally Posted by
DrIsotope
My Cervelo came with mid-compact, and I frankly hated it. I would never have been one to guess that a 2-tooth difference could make such a difference, but here we are. I swapped in a set of Praxis compact rings and never looked back. My wife runs "even more compact," with 46/34 rings. AFAIC, a 52 or 53 big ring is for people who are racing, people who like to think that they're racing, and people who never want to use the 11T cog again unless falling down the side of a mountain.
In curiosity I just ran a 52 and a 50 into the bikecalc.com site and got the following from 90 to 100rpm and it's a whole 1.4 mph difference. At 35mph.
A lot of A riders locally that I know that run mids and full size setups are absolute freaking pedal mashers. Their default spin has to be maybe 80rpm. If you can't be bothered to hold a cadence, sure, folks may need that.
I spin 90's mostly. 100+ for hard efforts and such. I can do just fine on a compact. I find not having to swap in-out of the big ring all the time to be nice when riding hills around town. I bet in a 52 or larger I'd probably have to constantly get in and out of the big ring. We've a lot of 2min hills here. That would suck.
If you own Di2 though, who cares about having to swap in/out. It'll do it for you. That changes things. Mechanical? Certainly compact for 90% of riders.