Question about SRAM eTap AXS: using different cassettes on trainer and wheels

In less than a month I will pull the trigger and order a new bike for myself, a 3T Strada with Force eTap AXS 1x and a 10-36 cassette. To say that I am excited is an understatement.

I need to get a second cassette for my indoor trainer, so I am considering two options: get another 10-36 cassette or opt for a 10-33 cassette. I definitely don’t need the 36-tooth cog on my indoor trainer, I doubt I’ll even use my 33-tooth cog a lot. However, I could hypothetically use a 10-33 cassette for crit races and flatter races.

So here is my question: apart from changing the cassette in the app, would I have to e. g. adjust the B-screw on the Force Wide rear derailleur? And what happens if I forget to change the cassette?

For indoor


So long as its a 12 speed cassette you should be fine. I could be wrong but I think it will be only be an issue if you were going larger than your bike cassette and not the other way round. meaning you’re using a 10-42 cassette on the trainer.

I use a 11 - 26 cassette on the trainer when I have an 11-34 cassette on my current bike. In ERG mode I only shift the from to off saddle for comfort reasons.

I don’t touch my derailleur screws as its more important for the derailleur to be tuned to my road cassette rather than my trainer cassette.

You could potentially have issues with noise but I wouldn’t think too much about it if it doesn’t.

Also is there a reason to change the cassette in the app? seems like a hassle to do it every time you swap from indoors to outdoors. I don’t have an electronic groupset but I would recommend you to not add steps to get your bike on the trainer each time as you will be doing it a lot.

hope it helps.

Yeah, indeed, which is also why I am asking. At the very least you need to it for synchro shift, which I am not going to use. But perhaps the derailleur adjust in other ways to the actual cassette — which is why I am asking. I can easily see me forgetting this, which is the main reason why I ask.