Originally Posted by burnthesheep

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.