Hi All

My Sram GX/Dt Swiss equipped bike makes an annoying rattle when the cassette engages. Does anyone know what could be causing this. It sounds awful, and makes an expensive bike seem a bit cheap.

I have uploaded a terrible but possibly quite useful video here: https://youtu.be/qwwA6R_hFC4

Thanks!

Pretty sure all my hubs (Shimano, DT, Hope, Chris King) make that noise? Are you expecting silence? It might quiet down a bit with a bit more grease in I guess?

Not expecting silence. This is just a lot louder and makes a real rattle when engaged. Much much more so than my previous XT with Superstar hub. You can hear the rattle right at the end of the video.

This is the cheaper of DT Swiss hubs if thats any relevance.

Double check the thru axle and cassette bolts are tight. Seems obvious but mine loosened over time and took a while to notice.

I think it’s probably mostly down to how many points of engagement your freehub has. The more degrees of rotation between each one, the more free movement before the “thunk”. I can’t really see why that would make it louder – surely an “unresisted” drivetrain must get up to speed almost instantaneously – but I bet it does (maybe that “almost” is important)

Maybe a little bit to do with materials too – some hub shells might be more, err, resonant? than others

Update on this: I’ve stripped the rear end down and have found that all is fine with the hub, free hub, and cassette. The noise is actually the spokes rattling, either against each other or in the hub or rim, I’m not sure which.

All spokes feel nice and tight. If I hold the spokes and engage the freehub the noise isn’t so bad. Normally it still makes a horrible rattling noise when changing down gears and on engagement.

DT wheels surely shouldn’t do this, should they? I’ve even tried lubricating between the spokes which made a tiny bit of difference, but is no cure.

Do I contact DT?

It’s not the hub, (budget) Sram cassettes are noisy like that in my experience. Having used both Shimano (XT) 10 speed and Sram (GX) 11 speed on two different DT hubs (spline, 240s) the Sram makes that sound on both, and Shimano doesn’t. I imagine it’s due to the construction methods of the two being extremely different. It annoyed me at first, but you’ll get used to it.