As a novice, I come seeking wisdom.

I have an old Rockhopper that I’m looking to strip down to the frame and rebuild into a commuter. I’ve been learning a lot about gearing and all that, and have been researching parts. I see that there are a lot of 1x10 groupsets and a very small number of 2x9, but nothing really with a lower number of gears on the cassette.

To my untrained mind, a 1x10 would introduce more stress and flex on the chain than a 2x5 would, especially while riding on the extremes. And, with a 2x5 setup, you could (probably?) have better ratios - I’m thinking it should be possible to set it up in a way where one chainring is better suited for climbing, and the other for higher speeds.

Yet, I don’t see any 2x5 or even 2x7 sets out there. What am I missing?

Another question: would it even be feasible to custom-build my own drivetrain with a 5-gear cassette, to use with 2 rings on the front, and if so, how complicated would it be?