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[Closed] GX Eagle drivetrain woes

Posts: 78
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[#11925280]

Afternoon,

Looking for advice on drivetrain issues. I've just replaced most of my GX eagle 1x12 - new cassette, chain (Sram Gx), jockey wheels (superstar) and chainring (burgtec gxp). As part of the installation I cleaned & regreased the crankset, freehub body and pawls (Hope Pro4).

My expectation of super clean shifting hasn't happened unfortunately - gears are still jumpy and in some of the middle gears there's lots of clicking noises, especially at high speed and under tension.

All I can think of is that the gear cables may be worn. They were installed Jan this year. When I've tried to index, I seem to struggle to get enough tension on the cable - the jumpy gears seem to want to go up to the bigger cogs even with the Barrel adjuster all the way clockwise. Would this indicate worn cables?

Any ideas generally?

Thanks

Dan


 
Posted : 17/06/2021 2:17 pm
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Have you got the b-tension screw adjusted properly? That can make a huge difference...how clean are the cables? Can you get some oil in to cable housing and gear shifter? That might help reduce friction in the cable system as well.


 
Posted : 17/06/2021 2:20 pm
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Gear hanger / dropout may be squint or bent.

Buy/borrow/steal some variation of this: Alignment tool at ChainReaction and it may well sort you.


 
Posted : 17/06/2021 2:21 pm
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IME GX is sensitive to the initial tension in the cable - too slack and even though you can wind on the barrel adjuster (which should have the same effect) you are plagued by the ticking in mid block.


 
Posted : 17/06/2021 2:24 pm
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Short answer is maybe - I don't have the tool so I set it following sram's instructions for without. I may be a mm or two out, can't be sure. Could a discrepancy this small have such an effect?

Cheers


 
Posted : 17/06/2021 2:25 pm
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Things that could be wrong:

Mech hanger slightly bent

Mech cage slightly bent

B screw wrong (if you’re in Bristol I have the white tool for the new style gx mech you can borrow)

Cable tension not right

Cable not routed correctly through the mech

Those superstar jockey wheels can sometimes cause an issue from stuff I’ve read online

Cable inners / outers need replacing


 
Posted : 17/06/2021 2:30 pm
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I had a similar issue with GX too. No matter what I did (new chain, cassette, jockey wheels etc.) I couldn't get clean shifting, under load I would occasionally get ghost shifts & lots of clicking.
The component that eventually fixed it was a new derailleur, there was a small amount of play in the pivot joints. If I put my finger over the pivot while wiggling it I could feel a small amount of movement.


 
Posted : 17/06/2021 5:10 pm