Originally Posted by
Barrettscv
I agree with your general summary, but some of the important details need to be explained by me so that you can see a difference in gear range.
It's a gravel bike and I'll be using tires in the 700x38 or larger tire size. The chainrings will be 46 & 33, using a Cyclocross crankset and installing an aftermarket 33t inner ring.
I'll stay on the big chainring on flat or downhill sections. I'll probably climb hills that are less than 4% without changing to the 33 chainring, I'll just stay on the 46 chainring and 28 cog on milder climbs.
Once the climb reduces my speed to 10 mph or less, I'll shift to the smaller 33 chainring and stay on that chainring until I hit 20 mph again. I'll be able to use either chainring in the 10 to 20 mph range, but will use the bigger ring as the preferred default.
Oh, I missed that this was a
gravel bike. My comments were for road riding.
Here' your setup in the gear calculator:
38c and 46/33
Attached is the speeds at high cadence. The 33 ring has much better shifts in the 15-20 mph range. If the road ahead looks like 20 mph or less, I'd stay in the 33 ring.
The cassette choices do depend on your expected speed ranges. For me, on gravel, I'd be optimizing my 5-15 mph range, instead of the 15-22 mph road range. Lots of choices.
See attached:
12-13-14-15-16-17-19-22-25-28-32 My example for fast road rides.
12-13-14-15-16-
18-20-22-25-28-32 This looks better for gravel, a more consistent set of shift gaps. This is your original plan.