12 speed SRAM drivetrain with 11 speed cassette possible on ERG mode?

[sjoerdth]

I’m wondering if it’s possible to use a 12 speed Sram on my trainer with an 11 speed cassette if I make sure to use the straightest possible chain line. If I put the trainer on ERG I wouldn’t need to shift, so I guess it should be fine, but I’m not sure, maybe I run the risk of damaging the chain or the cassette?

My GF also uses the trainer with an 11 speed shimano, so normally I just use another bike which also has an 11 speed shimano group. But I recently bought a new bike with Force AXS and I don’t want to change the cassette every time.

[JLopez149]

I have Force AXS on my bike and am using the 11spd cassette that came on my new Kickr. No issues. Shifts pretty well if you need to go up or down a gear or two. I don’t shift too often with ERG but if you need to it doesn’t seem to be any noisier or bind at all.

[spinnnout]

Not a direct answer but in the same situation with my bike on 11s and the trainer having a 10s cassette. Works fine.

Presumably the inner chain dimensions between 11 and 12s are the same and the 12s is narrower on the outside. If you can verify that, it will likely work though im sure the official SRAM party line is that it is not advised.

[sjoerdth]

I have Force AXS on my bike and am using the 11spd cassette that came on my new Kickr. No issues. Shifts pretty well if you need to go up or down a gear or two. I don’t shift too often with ERG but if you need to it doesn’t seem to be any noisier or bind at all.

Thanks, that’s really usefull (and promising) info.

Presumably the inner chain dimensions between 11 and 12s are the same and the 12s is narrower on the outside.

Aaah, I just presumed the inside dimensions would be slightly different, I’ll check it just to be sure.