So I’ve got a GX eagle set up, ridden 1800 miles, changed the chain at 800 miles and again before my last ride. Both chains were changed out when they got between 0.5 and 0.75 on the chain checker. Whilst changing the chain I also changed the chainring, from 32t to 34t.

I now get chain skipping but only when towards the bottom of the cassette and only when putting power through the chain. If I’m cruising along its all fine, even in the gears that jump under power. It was all fine before I changed the chain and chainring.

I’ve been through everything I can think of – cleaned everything, gears indexed perfectly, even checked the quick link was the right way round and connected correctly.

New chain and chainring are NX Eagle (and new), cassette and mech are GX eagle (and 1800 miles old). Is it possible that NX and GX aren’t compatible? Or have I got unlucky and the cassette has worn out quicker than I’d expect it to?

Has anyone else had similar issues or got any advice for fixing it?

They are compatible in sure.

So I’d suspect mech hanger or the cassette is now worn more than you think.

Oh, is there a lot of play in the mechs main pivot bolt?

I’d put one of your old chains back on – I suspect your cassette is too worn for a new one!

The cassette is worn

Cassette….

Sorry. Bucks… kerching

Is 1800 mines expected with 12 speed stuff?

Yep , sounds like chains were on too long if the cassette has worn too far within only 2 of them .

It all depends on where and how you ride but I never get anything like 800 to 900 miles per chain.Mine usually get changed ( at .75%) around 600 miles – the last one coming out of winter only made it to 357 miles.

You may be able to decrease the B Tension gap to get a bit more chain wrap around those smaller cogs and eek a bit more life out of it.Failing that as others have said it’s new cassette time I’m afraid.

You changed the chain. Regardless of wear indicator, you’ve got a new chain and part worn cassette. They are less likely to mesh and may skip at some point.

It’s (in my experience), false economy to bin decent chains that are a little worn and then end up having to bin perfectly good cassettes that are a little worn because new chain doesn’t work well with it.

Keep the old chain going with the cassette. I’ve done both methods, and wear it to death has saved me a lot of money and no skipping or shifting issues. I only end up changing the stuff when something needs an upgrade. Every couple of years basically.

It’s (IMO) bullshit about worn chain wearing cassette and chainring. It wears just the same new or old chain, just new meshes with new, old with old, not a mix of the two. Long standing myth though says you must change the chain early and frequently to “save” the cassette from wear. Usually in cooperation with a Park Tools chain checker who make a nice bit of dosh from those, and wouldn’t be surprised if they have shares in chain / cassette manufacturers too 😉

I’m with deadkenny.

I just use one chain and wear the drive train out.

Current one is years old and still works fine.

The jockey wheels are like sharpened death stars.

Put the old chain back on and ride it. And keep riding it.

Chucked the old chain already 😥

I’ve got a friend who runs 3 chains in rotation on his bikes, what do people think that doing that? Anyone else do it?

Tried it and it didn’t work for me.

I’m on gx eagle and I’ll run it till it skips then buy new lot

Although its skipped from new so I’m not sure when to change it now.

Whilst changing the chain I also changed the chainring, from 32t to 34t.

Did you check/adjust the B-Gap after putting the bigger chainring on?

With £39 cassettes and £10 chainrings I used to run for a couple of seasons and replace the lot. But now I have a £150 cassette, so will try changing chains at .5%.

Did you check/adjust the B-Gap after putting the bigger chainring on?

Not looked at that. Does it need adjusting for different chainring sizes? I’ve never done that before, and never stopped mid ride with I was changing between the triple chainring set up I had for 20 years

Eagle is super fussy to B tension – you need he red shark fin to ensure it’s set up right.

Did you reduce the chain length to accommodate the new, smaller ring – I’m not sure it is that but eagle does seem super fussy.

Does it need adjusting for different chainring sizes?

With Shimano you could get B-Gap roughly right and it worked. Eagle is v. fussy. In theory a larger chainring (same chain length?) could move the mech enough to impact performance.

Also if full-sus, try and check it in the sagged position.

if its that fussy how does it work with an oval ring?

and when you bobbing uphill?

I didn’t even get 600 miles out of my original eagle chain and cassette before they were knackered. New chain went on at 600 miles and slipped in bottom 4 cogs so I just ran the old chain and cassette until they died. To be fair this took another 600 miles before I replaced the chain and cassette so not too bad. I now just periodically change the chain every few months regardless of wear. They only cost £20 for gx so worth doing and makes the cassette last a few chains.

No experience of ovals, but assume once you’ve set it correctly, you’re reliant on the mech handling any slight change in tension. But if the starting point is wrong…

Unlikely to be bobbing uphill down the 11T end of the cassette?

I did measure the chain on the new chainring, I didn’t just go with the same length as the old one.

Even so, I suppose the mech could be in a slightly different position. Will check it.

I’ve started chain swapping with eagle, having 2 chains and rotating them every couple of hundred miles to match the wear. At nearly 1400 now and it’s still shifting like day 1. With powerlinks it only takes 2 minutes to swap them over and it gives a chance to properly clean the chain in a tub of degreaser.

I got nearly 6000 miles of out my road cassette doing that, and some mates on expensive campag stuff have got over 10,000 miles doing it with 3 chains.

10,000 miles doing it with 3 chains.

One chain, one cassette, same chainrings, pushing 8k miles. Road and gravel use.

Tried to do 3 chains rotation sometime ago, but can’t be ask anymore.

Use your drivetrain to death and replace everything in one go. Another bonus, you can extend buying period and use some bargains to stock up for the future.
That is at least my way of dealing with drivetrain wear and tear…

Cheers!
I.

Interesting split between people who just ride the drivetrain into the ground and those who keep on top of maintenance. Think I might be a ride it into the ground kind of guy after this experience

You have to find your own way with these things Swoosh.Wear is relative to usage,some mountain bike riders may not average 10 miles per week whiles others at the other end of the scale may be above 100 miles or even more .

I rotate three chains and I seem to get to wear them all out without problems. I think I end up using each chain at least three times. The whole thing is pretty loose by the end, but all works.