Chain “skipping” issue. Tried almost everything. Help?

extremedave

extremedave

Well-Known Member
Team MTBNJ Halter's
Bike is a 2016 Intense Tracer non-boost. 11 speed, 10-42 cassette, was XTR derailleur just changed to SLX, thought that was the issue.

Important: problem began randomly, not after any upgrade, service or crash. Was fine going up hally toe, came down, problem started the next climb. Figured I knocked the hanger alignment off somewhere, no biggie, right?

So: bike only does it in the 42 under heavy load. Feels like chain rips loose from the cogs. Doesn't do it every time but more often than not. Fine in next cog down. Never seems to jump down or up cassette either just skips. Really fun under load when it happens. Anyway!

Here’s what I’ve done over the last two weeks:
Replaced derailleur (new).
Chain measures between 25-50.
Swapped to different (but not new) cassette. Teeth look suspect but two cassettes doing the exact same thing? Maybe?
Checked hanger alignment with park tool.
Swapped rear wheel to known good.
I just went over the bike looking for a crack or worn bushing maybe shifting the triangle over. Seems ok?

I’m at a loss. Photo of cassette enclosed, 42 cog teeth don't look great but would be really odd to have exact symptoms on two different cassettes. Ready to toss bike into a river.
TIA!

Side note: if anyone has a decent 11 speed cassette around I will borrow or buy to experiment.
 

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chain hitting tire under load.
overfill tire, try again.

i have a 10-42 in the bin.won't be around until next week tho.
 
extremedave said:
Bike is a 2016 Intense Tracer non-boost. 11 speed, 10-42 cassette, was XTR derailleur just changed to SLX, thought that was the issue.

Important: problem began randomly, not after any upgrade, service or crash. Was fine going up hally toe, came down, problem started the next climb. Figured I knocked the hanger alignment off somewhere, no biggie, right?

So: bike only does it in the 42 under heavy load. Feels like chain rips loose from the cogs. Doesn't do it every time but more often than not. Fine in next cog down. Never seems to jump down or up cassette either just skips. Really fun under load when it happens. Anyway!

Here’s what I’ve done over the last two weeks:
Replaced derailleur (new).
Chain measures between 25-50.
Swapped to different (but not new) cassette. Teeth look suspect but two cassettes doing the exact same thing? Maybe?
Checked hanger alignment with park tool.
Swapped rear wheel to known good.
I just went over the bike looking for a crack or worn bushing maybe shifting the triangle over. Seems ok?

I’m at a loss. Photo of cassette enclosed, 42 cog teeth don't look great but would be really odd to have exact symptoms on two different cassettes. Ready to toss bike into a river.
TIA!

Side note: if anyone has a decent 11 speed cassette around I will borrow or buy to experiment.
Click to expand...
Maybe Free hub body loose? Scratch that, you said swapped wheel.

play in the linkage?
 
extremedave said:
Bike is a 2016 Intense Tracer non-boost. 11 speed, 10-42 cassette, was XTR derailleur just changed to SLX, thought that was the issue.

Important: problem began randomly, not after any upgrade, service or crash. Was fine going up hally toe, came down, problem started the next climb. Figured I knocked the hanger alignment off somewhere, no biggie, right?

So: bike only does it in the 42 under heavy load. Feels like chain rips loose from the cogs. Doesn't do it every time but more often than not. Fine in next cog down. Never seems to jump down or up cassette either just skips. Really fun under load when it happens. Anyway!

Here’s what I’ve done over the last two weeks:
Replaced derailleur (new).
Chain measures between 25-50.
Swapped to different (but not new) cassette. Teeth look suspect but two cassettes doing the exact same thing? Maybe?
Checked hanger alignment with park tool.
Swapped rear wheel to known good.
I just went over the bike looking for a crack or worn bushing maybe shifting the triangle over. Seems ok?

I’m at a loss. Photo of cassette enclosed, 42 cog teeth don't look great but would be really odd to have exact symptoms on two different cassettes. Ready to toss bike into a river.
TIA!

Side note: if anyone has a decent 11 speed cassette around I will borrow or buy to experiment.
Click to expand...
If you hadn't changed the wheel for a good one my best guess would have been the freehub engagement system (either pawl or ratchet) being somehow damaged/worn out.
 
B screw? Not enough chain wrap if somewhat short cage? Axle/hub tight? In the past I've had a hub that came loose and my pawls were skipping. Cassette teeth have seen better days doe.
 
Paul H said:
Looks like the only thing that wasn't looked at is the chainring
Click to expand...
it’s not that old, replaced near the end of last season cause of chain drops. Possible but kinda unlikely?
I was having b-screw drift with the previous derailleur which caused similar issues. At least it seemed to be the issue as after adjustment it corrected.

Low limit adjust is essentially disengaged. I was really banking on bent hanger as the root cause.

Chain wrap I could see if I’d changed anything but it started out of the blue.
Argh.
New bike then.
 
Also, are you sure that the chain is properly seated when on the biggest cog? That would replicate the behavior after changing the wheel. Could be as simple as a frayed shifter cable not pulling enough.
 
Is it possible to be running a boost chainline chainring on non boost bike ? Would cause lots of cross chaining in biggest cog
 
serviceguy said:
Also, are you sure that the chain is properly seated when on the biggest cog? That would replicate the behavior after changing the wheel. Could be as simple as a frayed shifter cable not pulling enough.
Click to expand...
I've changed plenty of shifters and derailleurs and feel like I've got a clue but this is worth looking into. Typically if the shifting is clean up and down the cassette cable tension is sound. But yeah maybe it's not going all the way up the cog even though it's engaging the big. Hmm.

Ryan.P said:
Is it possible to be running a boost chainline chainring on non boost bike ? Would cause lots of cross chaining in biggest cog
Click to expand...
I changed it long enough ago that it should have been a problem before, but maybe cumulative cross chain? I'll look.

I'm getting some outside input to check B screw again. Worth playing with also.
 
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