Indoor noise issue: Sram loud shifting?

General Discussion
#1

I live on the 3rd floor of a wooden apartment building. In order to make things quieter for my neighbors I recently replaced a fairly noisy kickr snap with a neo 2t. Everything is much quieter now except for upshifting to smaller cogs in the rear.

I have Sram apex 1x with the pg1130 11-42t cassette, and it often makes a loud clong noise when upshifting, like the chain is slamming down onto the smaller cog. I haven’t used a well-turned shimano system in a while, but I’m pretty sure it was a lot quieter when doing the same kind of shift.

Short of getting a new bike or replacing my entire drivetrain with shimano, is their anything I can do? Specifically I’m wondering if getting a shimano cassette might reduce the shifting noise? In swift I definitely don’t need the range of an 11-42t, so maybe a 105 or ultegra 11-28?

Thanks for any insight

#2

Hard to tell what the source of the shifting thunk is. Changing cassette could be beneficial if the size of the step between those smaller cogs is less.

Is it any quieter if you take the load off the chain before shifting? Not that that is a great solution, but if you lighten up on the pedals for a split second as you shift, that may help.

#3

I think you’re on to something there with the difference in cog sizes, the shimano I used to ride was 11-32t so smaller jumps.

When I’m not racing and I’m thinking about it I often can reduce or eliminate the clong by easing up at the right time. But when I’m pushing hard it’s tough to focus on that.

Based on your insight I was about to order a 105 11-28t, which seems likely that it would be quieter on the upshifts. But then I realized that I’d have to adjust the b screw every time I switch the bike between the trainer with 11-28 and the rear wheel with 11-42 for outdoor riding (which I need because I’m terrible at climbing).

Looks like it’s time for a cheap N+1 to keep on the trainer.

Thanks