[MrFish]

Mate of mine has just got a new Bontrager carbon wheelset and it was making a lot of spoke “pinging” sounds on a particularly rough high speed section at our bike park. Checked everything obvious and it seemed fine so I followed him closely and focused on the rear wheel of his bike, to my amazement I could watch the chain whip sideways on impacts, enough that it could strike the spokes. So suggested that he should shorten the chain, weird thing is that while cleaning my bike tonight I noticed I have similar marks on my spokes and rim on the drive side. Now I am confident that my chain is as short as I would like to go and it is an almost new drive train other than the derailleur. Completely different suspension systems too with one a Bronson B3 and the other a Kona Process, both running eagle but mine XO1 mechanical and his GX axis.
Anyone have any ideas or seen this before ?

 

[2021Mach6]

Mate of mine has just got a new Bontrager carbon wheelset and it was making a lot of spoke “pinging” sounds on a particularly rough high speed section at our bike park. Checked everything obvious and it seemed fine so I followed him closely and focused on the rear wheel of his bike, to my amazement I could watch the chain whip sideways on impacts, enough that it could strike the spokes. So suggested that he should shorten the chain, weird thing is that while cleaning my bike tonight I noticed I have similar marks on my spokes and rim on the drive side. Now I am confident that my chain is as short as I would like to go and it is an almost new drive train other than the derailleur. Completely different suspension systems too with one a Bronson B3 and the other a Kona Process, both running eagle but mine XO1 mechanical and his GX axis.
Anyone have any ideas or seen this before ?

1) Are you able to send a pic of your rear derailleur from the back (preferably in 1st gear)?

2) Do you experience it when you're in 1st gear only, or does that not matter?

3) Do you use a chain guide?

4) Is your chain worn out, and when was the last time it was replaced.

The only way I could see that happening is if your derailleur is bent.