I swapped chains on the tandem at the weekend as I realised the one fitted was quite stretched. It’s a shimano 11 speed dynasys set up, to which I fitted an SRAM PC1110 11 speed chain, and when we headed out on Tuesday there was a really weird noise whenever we put the power down. Other than cleaning, I didn’t make any other changes. I’ve had a good look this evening but I can’t figure out where the noise is coming from. Any ideas? (I’m about to try to attach two videos that I took on the phone while riding)
Edit: nope they’re too big to attach will try to shrink them
Was the old chain so stretched that it had worn the crank rings/cassette?
You did feed the chain through the rear mech correctly... ?
Rear mech was one of the first things I checked even before it came off the work stand, I’ve done that myself before
anyway I’ve managed to shrink the size, let’s try again
And I realise of course o should also have said it’s a Bosch motor with a very small cog inside the ring of the timing chain
still no idea if the videos have posted correctly
edit, checked on the Chromebook and I can see and hear them
It sounds a bit like the noise is present all the way through the chain’s rotation. Could it be a directional chain on backwards?
I can try swapping it, but it’s a cheap chain, I don’t think it’s likely to be directional. Worth trying though, it’s easy enough
Most likely wear on the sprockets/cog/chainring that aren't meshing with the new chain properly.
I've given up with preventative chain replacement after having this a couple of times and just run a drive set until it's all knackered then replace the lot.
Yeah, old chain left on for too long so the rings, etc are now a bit worn and not spreading the load properly. I'd do one of three things: Put up with the noise until it eventually beds in; put the old chain on and run it all in to the ground; replace all the worn stuff now.
It doesn't sound like a classically-worn drivetrain to me, more like something that shouldn't making light contact.
I'd be tempted to try a different, cheap chain. Decathlon own-brand is KMC X11
I still have the old chain, so I can try that - if the noise goes away then it's related to the new chain.
If I try the new chain in the other direction, that might help
I'm in the @timba camp, this sounds like something making contact rather than wear. When i've had an overly worn cassette in the past, the issue has been chain skip rather than noise. The drivetrain seems rock solid, but sometimes noisy.
I just can't trace it. It doesn't help that being on a tandem, it's a LONG way behind me, and it doesn't seem to happen in the workstand. It only seems to happen under load, like going uphill, and it seemed louder with a stoker using the rear crankset
Might not get chance to have another look until tomorrow, but will see what suggestions come up in the meantime and see what I can find when I get back to it
When i've had an overly worn cassette in the past, the issue has been chain skip rather than noise. The drivetrain seems rock solid, but sometimes noisy.
It doesn't need to be overly worn, just worn enough that the chain and ... something ... aren't compatible. I'd like to know what the solution is though, (particularly if I'm right!! 😁)
😀 Whereabouts are you? https://singletrackworld.com/forum/postid/13753985/
