Originally Posted by
scarleton
So, there are lots and lots of gearing options on a given bike. As a Clydesdale, did you put thought into the gearing of your bike? If so, why and what is the gearing?
50-39-30 x 13-14-15-16-17-18-19-21-23-26
One tooth jumps feel great through the 19 cog riding flatter terrain and are worth jumping through hoops (triple cranks, bigger first position sprocket, more cogs in back) to avoid changing cogs or wheels before rides. Keeping the big cog and starting with a 12 I'd loose the 18; 11 would drop the 16 which definitely wouldn't do. I tried a 14-23 10 cog straight block for a while - the 20 between 19 and 21 was slightly noticeable, 22 not, and the extra cogs were a hassle to skip over changing rings.
50x13 is a 45 MPH sprinting gear which is more than plenty for me. It's a comfortable down-hill or strong tail wind 30 MPH cruising gear; if I was in a situation where my power was enough to cruise faster it'd be steeper down-hill where I can go about as fast tucking. Eddy Merckx dominated the spring classics (like riding 130km off the front to a stage win and finishing the Tour de France with yellow, green, and polka dot jerseys) with a 52x13 big gear and none of us have Eddy's legs.
There's a lot to be said for learning to pedal faster
The 50 means one less cog to shift going up to the big ring so it's one shifter wiggle not two - following 39x14 the next gear is 50x17 not 53x18. The chain line is a little better and quieter moving to the big ring because I'm riding one cog closer to the dropout than with a 53 ring, like 50x18 instead of 50x19.
At 145 pounds I could get over anything in the Colorado Rockies with 42x28 or 30x21 and enjoy most of it. 30x26 comes close enough to allowing the same cadence at the same power but slower climbing speeds that go with 200 pounds. With more weight I'd run a small ring with fewer teeth to keep the one tooth jumps through the 19 cog. Having shrunk substantially this year I considered 12-23 to defer shifting to the big ring, although 13-26 has a better chain line after shifting up to it and if I need a burst of speed I can hit 30 MPH in 39x14.
I rode 50-34 for too long; there was way too much front ring shifting with the limited speed on the 34 ring which has cogs acting like ones two teeth bigger on a 39 ring and isn't silent on the small cog as with the middle ring on a triple so shifting to the big ring must happen three gears sooner on a compact than a road triple with the same cassette.
Before that I built my bike with a triple because given 50-40-30 x 13-21 8 speed without changing cogs I had a 13-19 straight block for plains rides east of Boulder, CO and low like 42x28 for mountain rides west.