Rear derailleur issues – SRAM

Hi,

I have SRAM XX1 on my 2018 Whyte and suffered the dreaded “stick in the spokes” the other month. That managed to break a few spokes and the lower jockey wheel which I’ve just got fixed, but now I have shifting issues (not unsurprisingly). It all started on my test ride after fixing the wheel. I got about 1 km into the ride and then the chain got caught between the lower jockey wheel and the cage. This happened every few meters so I gave up and freewheeled back. With the bike back in the stand I could see that in the higher toothed gears (32T+) the angle of the lower jockey wheel was such that it was not parallel to the chain – hence the locking issue. Obvious! I hear you cry – the stick incident has obviously bent the hanger! That was my thought too and so out came the hanger alignment tool. There was perhaps a slight bend to the hanger, but then again maybe not. I tweaked it and tested again – still an issue.

As it happens I have a newer GX derailleur on another bike, so I whipped that off and replaced the XX1 on the Whyte with the GX. A (not so quick) test ride showed that it performed flawlessly. That confirmed my thoughts about the hanger, so I set about making one small change at a time to try to find the component(s) that were causing the issue. I changed components in this order:

• New jockey wheels from the XX1 into the GX – still no issue
• Back of the cage from the XX1 into the GX – still no issue
• XX1 (fully reassembled) back on the Whyte – Issue

This makes me think that the main derailleur body (parallelogram?) is at fault. This leads me onto the point of this post – a question…

What, if anything, can I test next to help diagnose and fix the issue?

Thanks for getting this far. I look forward to hearing what you have to suggest (other than to buy a new derailleur).

Mike

What about the main cage plate being twisted/damaged – I’m assuming carbon so wouldn’t be twisted but may have damaged the mounting hardware ? Can you swap the cage ?

Hi Fossy,

The main cage plate is carbon (XX1 and X01 both are) so that’s unlikely to have twisted. I didn’t know they could be changed (hence not testing that) as I thought they were permanently fixed to the parallelogram but will go and investigate.

Mike

Did you change the mech hanger? I bet that is bent slightly and will be impacting the shifting…aware you’ve said you’ve tried a different mech, but I bet it isn’t quite right.

I didn’t change the hanger as the GX worked fine, so I presumed that the hanger was adequate.

When putting the old mech back on, did you redo the b-tension adjustment?

Have you got narrow wide teeth on the lower jockey wheel? I darkly recall some mechs have this and some don’t…

If it does have this jockey wheel is the chain sitting correctly and running smoothly?

A good suggestion about checking the b-screw when swapping the derailleurs over, but in this case I did (I had to with the GX owing to the frame geometry).

The old jocky wheels (the bottom one was destroyed in “the incident”) were narrow-wide but the newer replacements are all narrow.

With the newer wheels I don’t experience the symptom with the GX body but I do with the XX1 body.  I’m trying to find which component on the XX1 body is causing the issues.

I look forward to hearing what you have to suggest (other than to buy a new derailleur).

Buy a new derailleur.