Gears Slipping/jumping

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Whenever i am cycling up an ascent and putting pressure on the pedals the gears start slipping/jumping and even comes to a point where the chain comes off.It doesn't happen on the flat.
Although it does happen in the bigger cog it's mostly in the smaller cog(granny ring)and in the higher gears.
I know you have the barrel adjuster and the two limit screws but i'm reluctant to try this for fear of making it worse.
Rather than take it to my LBS i thought i would ask here first.
Cheers
 

fossyant

Ride It Like You Stole It!
Location
South Manchester
Worn chain/cassette ! You aren't going small small are you, as shifting ramps can try and shift the chain up
 

I like Skol

A Minging Manc...
IME even a badly worn drivetrain will work fairly well if correctly adjusted, until it gets to the point of sharks teeth on either the cassette or chainset. The problems generally start if one of the components are replaced (i.e chain, cassette or chainring) and you then get terrible meshing issues between the worn and new parts.

Has anything been changed recently?
 
OP
OP
The Central Scrutinizer
Location
Essex
How many km since you fitted a new chain?
How many km since you fitted a new cassette?
Chain maybe 1200 Kms
Cassette rough guess 10-11000 Kms
Here are some pictures of the chain with the wear check tool and the cassette.
 

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OP
OP
The Central Scrutinizer
Location
Essex
IME even a badly worn drivetrain will work fairly well if correctly adjusted, until it gets to the point of sharks teeth on either the cassette or chainset. The problems generally start if one of the components are replaced (i.e chain, cassette or chainring) and you then get terrible meshing issues between the worn and new parts.

Has anything been changed recently?
Only the chain when the bike went in for a service in february
 

I like Skol

A Minging Manc...
If the chain has run ok with this cassette until now I would be surprised for it to be a worn chain/cassette.

How are the teeth on the chainset looking? You might be investigating the wrong end or maybe the indexing has shifted for some reason.
 
OP
OP
The Central Scrutinizer
Location
Essex
Yes you've posted some good pics of the Chain and Cassette could you post some up of the Chainwheels ? Though I'm sure that some more adjusting of the Rear derailleur could be perhaps fortuitous? do you experience the same faults when bike is in the work stand ?
There is no skipping when the bike is on the stand.
 

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Ajax Bay

Guru
Location
East Devon
11,000+ km is a great longevity for a cassette to have achieved. Very surprised the new chain didn't immediately skate on first use (and every high torque use/occasion) - maybe it did: the OP does not say/exclude.
Replace cassette and chain at your earliest convenience. The chain will be close to or beyond 0.5% elongated already. If just the cassette is replaced, the 'old' chain (1200km on it) will skate on the 'new' cassette.
No skating on the stand would be expected: you can't get anywhere near the power needed.
 
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I like Skol

A Minging Manc...
@Ajax Bay
Thanks for your input and everybody else who posted.
The gears have only been playing up in the last week.
I’m going to take it in to my LBO and see what they say.

In view of this vvvvv comment, probably the best solution really. :laugh:
I know you have the barrel adjuster and the two limit screws but i'm reluctant to try this for fear of making it worse.

Could be sub-optimal indexing, but in view of the cassette age I think a new cassette & chain is probably sensible, even though on the face of it they don't appear to be in terrible condition.
 
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