1x drivetrains for road: selecting gearing (Part 2)

Selecting the gear ratios is the easy part. You go HERE and input what you are currently riding, then try and mimic this with a single cassette.


I am of the firm opinion that all bikes are sold with bigger (longer, greater gain ratio, or bigger Gear Inches) gears than the average strength rider can push. I know that I have never spun out a road bike with a 50/11, and the descents into Bartlett Lake are among the longest and fastest descents I’ve ridden, barely spinning out a 46/11 at over 40mph in an all-out effort. So I think it is fair to say that I don’t really need anything over 100 Gear Inches.


My CrossCheck had a 34/46 with an 11-32 cassette (8 speed), my new setup is a 40t Origin8 narrow-wide and a Sunrace 11-40 cassette. I dropped a couple of gear inches off the top end, and gained a couple at the lower end, based on how I use the gears. In detail, I had 29-84 gear inches and 39-114 gear inches: now I have chosen to have a single sweep from 27-99 gear inches. From riding, it seems like at the lower end of the ratios I have an rpm difference of around 5 between sprockets, and at the higher end it is around 10: this is vaguely comparable to a road setup and oddly similar ratio spacing to my previous setup, but its all on one shifter, simple and linear.

This is my gearing comparison HERE.

After a few commutes, my only comment is that the 40t is too close to the 36t in pedalling rpm, so I may opt for the 11-42 on my next build (the only difference is the biggest ring), sticking with a 40t chainring, rather than changing the tooth count on the chainring (this will probably be a gravel monster, SRAM equipped and with a power meter).

Tobias Feltus: