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Nasty chain slip. What may be causing it?

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Nasty chain slip. What may be causing it?

Old 05-19-19, 01:01 PM
  #26  
zacster
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I had a bike where it skipped under load and it was the big chainring. The bike was bought used and I'd swapped out all the rear parts but left the original crank and chainrings, plus I put 10sp on to replace 7sp. I put a new 10sp chainring on and problem solved. The middle and small are still the original but I can't remember the last time I used either.
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Old 05-19-19, 01:18 PM
  #27  
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Originally Posted by zacster View Post
I had a bike where it skipped under load and it was the big chainring. The bike was bought used and I'd swapped out all the rear parts but left the original crank and chainrings, plus I put 10sp on to replace 7sp. I put a new 10sp chainring on and problem solved. The middle and small are still the original but I can't remember the last time I used either.
I do suspect it could be the rings. I'm going to go for a ride tomorrow and use the little ring to see if I can get the thing to slip.
50t 9000 rings seem rare to come by so I'm thinking of getting some absoluteBLACK. Hopefully they are half decent.
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Old 05-19-19, 01:22 PM
  #28  
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Originally Posted by Trakhak View Post
Replacing the cassette often means that the either or both derailleurs will need to be readjusted, since the new cassette may be positioned slightly inboard or outboard of where the original cassette was positioned. Your description of the chain dropping off the crankset and the chain failing to index correctly on the cassette sprockets suggests that you should check both derailleurs.

Also, for best cassette life, try to get in the habit of using the big chainring in combination with the middle cassette sprockets rather than the smaller chainring(s) in combination with the smallest cassette sprockets for riding on level ground at speed.
From what I can tell though, the derailleurs are adjusted ok. The rear is not allowing any travel past the top of bottom of casette body if I try to get to to, and the front looks to be less than a mm from the outer edge of the chain on both high/low limit. Gear changes are also instant and accurate, as far as I can tell anyway, I'm sure I would've noticed.
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Old 05-19-19, 05:04 PM
  #29  
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Originally Posted by dja1 View Post
I do suspect it could be the rings. I'm going to go for a ride tomorrow and use the little ring to see if I can get the thing to slip.
50t 9000 rings seem rare to come by so I'm thinking of getting some absoluteBLACK. Hopefully they are half decent.
Yes, that's what convinced me it was the ring. I rode for a few days in the middle ring and never had a problem, then switched back to the big one and it slipped immediately.

Wait, I just looked at the pictures. That bike is too new to have that issue. My problem bike was almost 20 years old.
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Old 05-19-19, 05:06 PM
  #30  
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Originally Posted by dja1 View Post
50t 9000 rings seem rare to come by so I'm thinking of getting some absoluteBLACK. Hopefully they are half decent.
AB rings are more than half decent, they're quality kit.
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Old 05-20-19, 01:51 PM
  #31  
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One of the lads from cycling club looked at the bike today. When back pedalling stationary, he noticed that the chain was jumping off the casette slightly where it meets the teeth at the top of the casette. He thinks that the chain may be too wide for the casette, even thought it is a KMC-11 speed which is supposed to be compatible with shimano road derailleurs. Kind of hard to tell, but I do think it looks ever so slightly wider than the 11-sp shimano chain on his bike, so I'm thinking that I may try yet another chain. A shimano ultegra one this time, just like the old one I had on the bike which gave me no issues. Could this finally be the solution?
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Old 05-20-19, 01:58 PM
  #32  
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Originally Posted by dja1 View Post
One of the lads from cycling club looked at the bike today. When back pedalling stationary, he noticed that the chain was jumping off the casette slightly where it meets the teeth at the top of the casette. He thinks that the chain may be too wide for the casette, even thought it is a KMC-11 speed which is supposed to be compatible with shimano road derailleurs. Kind of hard to tell, but I do think it looks ever so slightly wider than the 11-sp shimano chain on his bike, so I'm thinking that I may try yet another chain. A shimano ultegra one this time, just like the old one I had on the bike which gave me no issues. Could this finally be the solution?
It would tick every box if it were the solution.

Could be someone opened the box and put the wrong chain back in, or it got mis-labeled somehow. I hate spending the extra money for Shimano stuff, but it looks like it's justified here, that's some really nice gear you're running. No point in having Dura Ace if it's not gonna run flawlessly.
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