Originally Posted by
UnfilteredDregs
So you assumed I was moving from a compact. Agreed 50-52 ain't that much there.
What's so big about the gear jumps in the comparison chart above? The gear steps from 18-28mph is accounted for, the exception being 23mph @13% but that can be crosschained (36x11) at worst if the gap proves troublesome and the bike is set up to do so.
The difference between a 52 and 46 is almost 15 gear inches with my current setup. That puts the top two cogs within a higher speed bracket at a given rpm where I can gain an additional 3mph. but, it isn't about the academic finite here. It's about placing gears at a point where I can much more effectively maintain speed or accelerate via torque instead of spinning like a hamster. Descending at speed places more emphasis on maintaining momentum against drag versus being on the flats. I spin out 46x11 regularly where I live.
I see no disadvantage going to a 52/36 and 11-32. That maintains my lowest gear requirement which is for anything sustained at 13% and up,
The big disadvantage is the huge gap between the 15 and the 17. That is the difference between 21.5mph and 24.3mph @90rpm. What happens when you want to hold 23mph? You either have to ride 52x17@~100rpm or 52x15@85rpm. A jump of 15rpm is huge in a paceline IME. Doable? Sure. Optimal? Not really. So why not run 50/34 11-28? That decreases your GI range slightly, but the difference in cadence at the extreme ends of your gearing are smaller than in the middle with the 52-36 11-32.