New chain and sprocket jumps

[DaveTheRave]

Hi All,

After around 4000 miles I had a problem with my Claud Butler Urban 200 chain jumping.
The chain was well worn, so I replaced it.
Then the new chain jump at the slightest load (maybe this is not so surprising) so the bike was unrideable.
This was because the rear gear block was worn. I replaced the rear gear block (and free wheel - its all in one).

So now I have new chain and rear gear block, but the chain still jumps when under moderate to heavy load. So my question is does a new chain and sprocket required "running in", ie will it take some time before the fit is perfect, or should it be 100% straight away?

Thanks for your help
Regards
Dave

[stutho]

How long did you run the new chain with the old block?

[Andrew]

quote:Originally posted by DaveTheRave

Hi All,

After around 4000 miles I had a problem with my Claud Butler Urban 200 chain jumping.
The chain was well worn, so I replaced it.
Then the new chain jump at the slightest load (maybe this is not so surprising) so the bike was unrideable.
This was because the rear gear block was worn. I replaced the rear gear block (and free wheel - its all in one).

So now I have new chain and rear gear block, but the chain still jumps when under moderate to heavy load. So my question is does a new chain and sprocket required "running in", ie will it take some time before the fit is perfect, or should it be 100% straight away?

Thanks for your help
Regards
Dave

Hi Dave,

A new chain and cassette/freewheel will mesh perfectly together, there is no running in required. I suspect it is the chain slipping on the front chainrings. If the chainrings are heavily worn then a new chain will not mesh with them, resulting in the chain slipping under any load.

Andrew

[DaveTheRave]

Thanks for replying

quote:How long did you run the new chain with the old block?

No distance, probably about 100 metres.

 

quote:A new chain and cassette/freewheel will mesh perfectly together, there is no running in required. I suspect it is the chain slipping on the front chainrings. If the chainrings are heavily worn then a new chain will not mesh with them, resulting in the chain slipping under any load.

I'm fairly sure the jumping is at the back end, but I could be wrong, I will check next time I go for a ride (in about 10minutes).

Regards
Dave

[DaveTheRave]

Andrew,

I think you are right, its hard to see where the problem is, but I'm sure on one occassion when it jumped I saw the chain not running correctly around the front chain rings.

Many thanks for your help []

Regards
Dave

[DaveTheRave]

Hello all,

A final update;
I fitted a new crank set (its a cheap once piece so it all had to be replaced) and that cured my problem []

So you guys were right, thanks for the help.

Regards
Dave