Hi all

I’ve got a Sram Eagle GX drive train on my YT capra. It has been absolutely faultless for many miles and seriously impressed with the longevity of the cassette.

However the last few weeks I’m having problems with it jumping gears or ghost shifting about 2/3rds down the cassette. It either won’t shift into that gear, or when it does its constantly jumping up and down or actually the chain bouncing on that gear.

I’ll admit that the cassette has done thousands of miles, but surely this wouldn’t be the cause suddenly.

New inner and outer cables changed twice because I was convinced it was the cable. Indexed as I normally do and B tension set correctly. Even changed to XTR cables to reduce friction.

Any ideas please guys. Thanks alot

I’ll admit that the cassette has done thousands of miles, but surely this wouldn’t be the cause suddenly.

At some point in time, everything goes from working to not working.

Wear can mean that you just bend a chain or tooth, perhaps have one set of teeth that are just beyond proper function.

Buy the new items you need and compare with the worn – and you then have the new items to replace the old with.

Mech hanger alignment is the first thing I’d check
Also check that the cable is running cleanly (has it been replaced recently? could be full of gunk and have excessive friction). An easy check for this is whether the shifting issues are both on the way up and down the cassette.

Mech hanger alignment is the first thing I’d check

+1

I’d also check the derailleur itself for play as well, I had a similar issue and it was the parallelogram having developed play, was wobbling about all over the place.

After the mech hanger check the jockey wheels for play. When I first had the GX drivetrain it was brilliant for the first year and then became sloppy and I think it was the jockey wheels.

Thanks all for the replies.

Swapped the hanger tonight and it’s slightly better. But in all honesty I think it’s because the whole set up is worn. The chain measure gauge is dropping through at 0.75 and 1 is also fitting through.

Really can’t fault the gx eagle set up and longevity though.

The rotation of chains seems to have helped.
Do you think a 3rd chain would be worth a try or do you think it’s guaranteed to slip? And would you thrash it through the winter deal with it ghosting or put fresh on for a muddy winter?

Just to add to this guys. This issue is worse when the chain is a bit muddy. Cleaner the chain the better it is. So I guess it is due to wear?

Swapped the hanger tonight and it’s slightly better.

I’d still check the alignment. Neither the replacement hanger nor the frame itself are certain to be dead straight, so it’s normal for a degree of adjusting to be needed.

I’m following with interest for tips and lessons for if and when my GX starts playing up in the future !

What you’ll probably find happening is you’ll go through all the usual trouble shooting techniques and eventually just put a new one on and it works perfectly then you’ll wish you just did that in the first place.

Get this constantly at work. It’s frustrating.

Not a fan of SRAM mechs now due to this. Had this happen on fairly new and or undamaged ones. They trick you into messing on trying to get it working 😂

I had similar issues. Checked hanger, b-screw, swapped cable, checked chain all to no avail. Swapped mech from another bike and it worked fine. I noticed the jockey wheels were very loose and worn so tried new ones but it made no difference. After a couple of weekend trips away the replacement mech started playing up to. Tried it back on the original bike and still had problems. In the end I decided just to try a new mech so got a SLX 12 speed. It worked perfectly – so well I got another for the other bike. That was perfect to. So in the end it was just worn out GX Eagle mechs. No obvious damage but clearly beyond their useful life. I’d suggest getting a new mech if you’ve tried the obvious, simple solutions. If nothing else it will rule that out and you’ll have a spare!

I had repeated difficulties with a GX rear mech. Even though it hadn’t done many miles, and I cant recall knocking it, a couple of the pivot pins were slightly bent which was affecting shifting. Only discovered the problem after replacing it with an XX1 and taking the old one apart. Could well have been like that since new, as, from new, shifting wasn’t as it should have been. If it’s developed gradually, I’d always suspect cables.

its constantly jumping up and down or actually the chain bouncing on that gear.

I had this thinking my GX cassette had finally worn out but it was the front GX alloy chainring. Switched back to my spare steel NX ring and the chain skip in the higher gears went away. Cassette still going strong, thankfully.

I found the solution was to put a shimano and mech and shifter on. XT shifter SLX mech. Problem solved

I had the exact same issue on the weekend, chain bouncing around in the smaller cogs, slow on some down shifts or some no shift shifts, chucked the mech hanger alignment on it yesterday and it was out going from north to south, used the tool to bend it back and rode today with no issues, it was almost like it was new again! Must have been bent for awhile.

I had similar issue and could not find anything written online.
I am running DT Swiss XMC 501 spline 30 . This problem happened after 1 year and ~4000 miles
Those the hub is DT Swiss 240.

Checked the hanger the , replaced the pulleys, replaced the cassette, put a new XX1 AXS derailleur.
Gradually had some improvements limited the problem from as you said 2/3 of teh casset to teh bottom 3 cogs( 10-11,12 speed, the smallest ones) .
What I found out is that bearings of the cassette were worn out due to the fact that I wash the bike often. I do not use power washer but have a very high pressure garden house with a thin and kind of jet washer.
The fix is to replace both bearings of the hub and replace the free hub body or the bearings that are damaged.

My problem was busted bearings . When i replaced the hub bearings the gear shifting was very good on the stand but still had problems with shifting at the highest 3 gears especially under load .
New free hub or( new bearings) fixed the problem.
What happen is that when you push on the cranks and the chain pulls the crassest , if the free-hub body bearings have -play then you torque the cassette and loose alignment.
So fix for shifting issues is checking in this order:
-Hanger alignment
-Chain
-Cable house
-Pulley wheels
-play in the derailleur
-bearings in the free-hub body
-bearings in the hub
Good luck

All above for me played out in a thread last week. It turns out the cage is very slight twisted due an impact plus there’s some play in the mech which means the tension varies across the cassette.

To be fair mines done 4.5 years of riding and xc racing (most recently yesterday) but I have an XT mech in the post due to price /availability.

Had similar with mine on 2 bikes within weeks of each other. Replaced cables/outers, checked hanger alignment, replaced jockey wheels, new chain……..etc. Nothing worked. In the end I changed the mechs for Shimano SLX and the problem was solved. The mechs were simply worn out. They had done pretty well and I would have got the same again but availability was poor and very expensive. The SLX works just as well and was half the price. Let’s see how long it lasts.