Been fine for months all of a sudden gear 8 and 9 try to jump?

I’ve tried B screw job. Improves but not perfect. No hits to the mech or hanger.

Could it simply just be chain wear?

Your gears have been hacked by the Chinese / a Nigerian prince.

Sorry, nothing helpful to say.

Is the cassette wobbling on the freehub?

Checked cassettes. But will double check if that’s a thing. Ta

Hanger alignment, get the tool and check it, however straight your hanger looks

I’ve tried two hangers.

And it’s not been knocked.

But quite fancy one of those tools.

Shift to middle of cassette
Wobble mech side to side (relatively) firmly from bottom of mech
See if there’s play in parallelogram pins
If so, warranty if <2 years old

That’s what I did.

It wasn’t the hanger… Didn’t even check it as the play was so **** obvious. Worked spot on with the XX1 MechanEagle and the warranty GX AXS mechs.

And check for play in top jockey wheel as well

Ah now it does have a fair bit of play.

I noticed that. But thought it inherent.

Thanks.

On mine I could see massive slack in one pin

Is this likely going to happen to all those mechs?

Or just GX?

Can’t be doing with this every 10months.

Is this likely going to happen to all those mechs?

JUst been out to check mine, it seems fine. Its a GX AXS mech, just under 2 years old, probably covered 2000 off road miles in all weathers.

Mine’a done 3000 8sh since oct 21.

Makes a bit of a clicking noise when moved.

Thanks – will examine.

Not just GX, can happen on all older AXS. My 3 year old X01 was starting to do this. SRAM have updated design so shouldn’t happen as much, but still a bummer for those of us out of warranty.

Found a thread about it on MTBR and there is a fix if it’s not too bad. Improved things for me and also added it to my XX1 on other bike. It’s lower mileage and still fine but would rather prevent any future issue.

https://www.mtbr.com/threads/axs-eagle-worn-pivot-arm.1204149/#post-15625044

Thanks for the link to the mtbr thread,I just checked my derailleur and it doesn’t have the screw in that pivot,but thankfully it hasn’t lost the bush from it yet,so I’ve just added a screw.

I’ve tried two hangers.

And it’s not been knocked.

Means nothing, unless the hanger is aligned to the cassette/wheel, with the tool, you can’t say with confidence that it’s straight

But quite fancy one of those tools.

Just do it…

So I forgot I’d got an alignment tool! Idiot.

Sorted that and still jumping about.

I’m now thinkg that the cassette is probably shot at 3300 miles. Given it’s jumping in the most used cogs.

.I’m now thinkg that the cassette is probably shot at 3300 miles

You said up there that your derailleur had a fair bit of play, is the jumping not being caused by that play?

The issue is Modern Mech Technology.

You said up there that your derailleur had a fair bit of play, is the jumping not being caused by that play?

I replaced the b-screw as I thought that’s where the play was coming from.

I’ve got no real reference point for play to be honest.

I’m not sure about the play at all as I can’t remember how much it moved from new.

Why would it only skip in 8/9/10?

The issue is Modern Mech Technology

Very good that.

Why would it only skip in 8/9/10?

Combination of worn cassette in those teeth and the basic geometry of the mech, plus the reduced wrap round the sprockets. Many/Any reason really.

I’m genuinely amazed electronic shifting still needs the hanger aligned

I’m genuinely amazed electronic shifting still needs the hanger aligned

You’d think that there would be a way to set position for 1st and 12th and it interpolate for all the rest. Which would then accommodate a little alignment error (accepted it probably wouldn’t accommodate a huge amount, but some, surely?). But it doesn’t work like that. You’ve just got up-down micro-adjustment, no effect on the gear-to-gear distance. To me this is a bit of a shame. Although I’m also a hanger alignment tool obsessive, so my hanger is dead straight. And right now my shifting has suddenly gone a little off, but I need to look at chain (old checker starts at 0.75%, so that’s now not much use), cassette and (please no) the possibility of a bent mech.

Oh and I was surprised to find that my B tension had slackened off quite substantially by itself. It was miles off. Vibrations causing the bolt to rotate? It was from a day clattering about at BPW.

Back to the OP – I recently had a cassette with some damage (or a manufacturing issue) very early in its life. Jumped under power in one cog. I worked on it for ages making absolutely sure I had indexing bang on before I could be 100% sure it was one cog and there wasn’t also an indexing/alignnent/whatever issue. If indexing is absolutely perfect and there’s never a ghost shift but consistent jumping then it sounds like cassette wear, or at least something between cassette and chain. Though I previously also had a freehub bearing go far too quickly, so it’s all worth a proper check. Microspline/XD Hope freehubs being smaller than HG have to accommodate smaller bearings and IME they don’t last as long as a result.

Well I will find out today. I’ve got an 12 xtr cassette to swap on to my hope pro 4 (which was previously on SRAM x01 12) so needed to order the freehub.

I’ve no idea what is a good amount of miles for a cassette these days.

I really don’t want to go back to wired shifting though!

’m genuinely amazed electronic shifting still needs the hanger aligned

It works with electric to replace the mechanical cable, not magic. How would the mech be able to allow for out of square and plumb in reference to the cassette? It’s still a mechanical device that requires things to be in tolerance to perform.

I’ve no idea what is a good amount of miles for a cassette these days

Me neither, but I know an XTR won’t last anywhere near as long as a SRAM under normal circumstances.

Is you b-tension bolt still in the correct location. My GX AXS came loose the 1st time I used it, not moved since. My XX1 AXS has always been perfect.

Is you b-tension bolt still in the correct location. My GX AXS came loose the 1st time I used it, not moved since. My XX1 AXS has always been perfect.

Yup this is what mine’s just done, but after 6 months in use. I was surprised – I don’t recall this on any previous mech. Will probably take it out and use some new thread lock on it