At first, FSA patterned everything they made after the most popular component brand of the time, Shimano. This guaranteed compatibility between their parts and Shimano’s other parts. So they could run their cranks on Shimano laden bikes. This also lets me swap out the 39 tooth inner stock chainring with a 38 tooth FSA unit. you may ask, “What’s the point?” but the point is, for $22 delivered, why not give it a shot. The difference is 2.5% better climbing gear ratio.
How was rideability? Shifting? chain engagement? Well to answer that in one word is easy. EASY. Done. This was a partial refit. For $100, I got a new 11-32 cassette, 10 speed Shimano 5700 rear derailleur, and the inside ring. It now has some climbing ability but how good? Well, more math!
my Soma with climbing gears: 34 x 32= 1.06+ wheel revolutions per crank rpm.
CAAD9 with mish mash parts: 38 x 32= 1.187+ wheel rpms per crank rpm.
CAAD9 with 39 x 32? 1.218 wheel rpm’s per… you get it by now.
And after all of this and a good ride up a good hill to test everything, I reach the conclusion of why manufacturers choose their difference in chainrings. It’s so when swapping from one ring to the other, you can change a few cogs in the back and have the exact same ratio. Convenient, I understand, however, what I did does mess that up a bit. Only by a small amount, and that might be beneficial overall. And overall, I don’t really care about one or two RPM different, that’s what I was looking for anyway on a gear change. It shifts just fine on the front.
I see a shimano 50 x 34 crank in my size on craigslist for $60. Unused! WTF. It’s an RS565 crank, so it’s not quite a 105 but it’s not yet a Tiagra level crank. For training? It’s great unit for that, plus the chainrings can completely swap out with other FSA rings. At least I have the rear end all set up. I think I’ll get it on Wednesday if I can and then this thing will be on the trainer by months end, ready to take on wattopia on the computer.