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Discussion Starter · #1 ·
Blah I have a new problem where the chain is popping down to a smaller cog under extreme power. This only seems to happen on the larger half of the cassette and primarily the middle cogs on the larger half.

The der seems to be a in good adjustment as the shifting works well. If I adjust it to try and compensate, then it doesn't shift as good. The hanger and der mounting seems tight. The der seems to be ok (I have 2173 miles on it) I don't think it is bent or anything (plus it is CNC billet der hanger). I replaced the chain back in the fall. I also replaced the housing/cable back then. There might be a little drag now though due to stupid winter so I might replace it again.

The other thing is that I have 1619 hard miles on this XT cassette... could it just be worn out already?

I just recently completed a 29 mile and 21 mile race. I have another on weekend after this weekend so I'd like to get this sorted out quickly.

Any thoughts?

EDIT: This is on a alu HT btw.
 

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I think I'd start by checking the derailleur hanger alignment and installing a new cable and housing. If that doesn't help then yeah, your cassette is probably toast. If you replace that you should install a new chain at the same time.
 

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Discussion Starter · #4 ·
What front ring are you in when it happens? What is the front setup - 1X10,2x10,3X10?
It's a 3x10 setup and I'm in the middle ring so the chainline should be pretty straight.
 

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It may be new cassette time, but I would adjust the b-tension to make sure you have the maximum amount of chainwrap possible.

To set mine, I shift the RD into first gear (largest cog), and then backpedal while backing out the b-screw until I hear interference with the jockey wheel and the cog. Then I tighten the b-screw about 1/4 turn.
 

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Discussion Starter · #6 ·
Alright, I'll try to look at all these things tonight.
 

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Discussion Starter · #7 ·
Yeah the cassette is toast. lol. One of the middle cogs is busted loose and can wiggle it from side to side. I musta busted it at Barry Roubaix.

Now the next adventure is getting the hub busted loose from the soft alu hub body the cogs are dug into on the Stand 3.30 hub.

Any tips on that?
 

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Discussion Starter · #8 ·
I just pried them off with a screwdriver...

Anyways two of the rivets holding the center cog assembly together busted apart.

Sent from my SAMSUNG-SGH-I337 using Tapatalk 2
 

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Discussion Starter · #10 ·
Nah my alignment and adjustment seems fine...

I say this as the only cogs I was having this problem with was on was that middle group that is busted. One of the cogs is so loose you can push it with your finger and touch the cog next to it. That's how busted that middle assembly is.
 

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Discussion Starter · #11 ·
Assy #8 is the one that's all falling apart. The cogs aren't really held together anymore.

24882_0_Ersatzritzel_Shimano_XT_Cassette_10fach.jpg
 

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Discussion Starter · #12 ·
Damn I just broke the replacement XT cassette! Right around 1700 miles again too! Uhg! This time the biggest cog on #8 got all bent up lol.

I just discovered it today. I hadn't been on the bike in 18 days due to clavicle recovery and weather conditions. Back on the first went out on the Chilly Challenge New Years day ride and at one point my bike started pedaling funny at times. That when it broke but I didn't figure it out till today, it was really cold that day.
 

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Discussion Starter · #13 ·
Here's a pic:

XT.jpg
 

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Also check of your chain is still ok. There's a tool you can get for that.

A stretched chain wreaks havok on cassettes and chainrings.
 

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I think that thing broke itself on purpose, screaming in agony it was.

Looks pretty hashed.
lol...weld.

aye, she deserves a good burial, mate. that one has done yuh some good work through the miles!
 

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At one point I thought I had the same problem: shifting was good, but under power (esp. on larger cogs) the chain would jump and crack, or so I thought.

Turned out the tiny pawls of the Mavic freehub were worn. The chain was on the cog all the way, it was just the freehub that slipped.
 
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