Jumping gears

[Plax]

My chain is jumping. It is fine in the higher gears (smaller sprockets on the cassette), but once you go into the lower gears it will make a kind of clicking noise and "jumps" so that the chain slips (very annoying on the hills, nearly came a cropper for one).

I was thinking perhaps worn cassette (I changed the chain but not the cassette), but it was perfectly fine to begin with. I tried changing the gear cables and cleaned and lubed the rear mech & jockey wheels and now it does it still, but on different gears than previously (instead of the second lowest sprocket at the back, it is now the lowest sprocket at the back etc). I'd have thought that if it was the cassette it would be on the same sprockets every time?

Also to begin with I could use all the rear gears on the middle chain ring, and it would only jump on the lowest gears when using the granny ring. Now it does it regardless of what chain ring I'm in.

Any ideas before I ask Santa for a new chain and cassette to see if that solves it.

Ta

 

[ttcycle]

Have you tried adjusting the indexing of the gears? It's either adjusted by turning the barrel at the rear mech or via the screws located on the rear mech/derailleur itself.

If that doesn't sort it out - could possibly be the casette.

 

[accountantpete]

I'd try the following

1) Take the cassette off,give it a good clean and then replace making sure that that the lockring is tight - I've often seen cassettes work loose, muck gets in and the spacings get messed with.

or

2)Turn the bike upside down and slowly turn the pedal by hand.

Look how the chain settles on the cassette - if the rear mech needs adjusting you should see the chain brushing the adjacent sprocket slightly and causing the noise that you have heard.

 

[AlanW]

If you have replaced the chain and NOT the cassette you may have answered your own question?

If the chain has worn past 0.8mm then the chances are that the cassette is knackered as well.

My rule of thumb is three chain replacements, if replaced at 0.8mm wear, on the fourth chain fit a new cassette.

In saying that I have just fitted a my third new chain and I was having the same problems, so fitted a new cassette and its back to being sweet changing again.


So you might want to invest in a chain checking tool, ie Park Tools or similar.

 

[potsy]

Forget all the previous advice Plax,just go and buy yourself a new bike
You know you want to.

 

[Plax]

If you have replaced the chain and NOT the cassette you may have answered your own question?

If the chain has worn past 0.8mm then the chances are that the cassette is knackered as well.

My rule of thumb is three chain replacements, if replaced at 0.8mm wear, on the fourth chain fit a new cassette.

In saying that I have just fitted a my third new chain and I was having the same problems, so fitted a new cassette and its back to being sweet changing again.


So you might want to invest in a chain checking tool, ie Park Tools or similar.

I have a chain tool, and the chain I took off still had plenty of life left in it, I was just trying a bit of preventative maintenance in changing the chain early........ Perhaps would have been better off leaving both wear out together.

I'd try the following

1) Take the cassette off,give it a good clean and then replace making sure that that the lockring is tight - I've often seen cassettes work loose, muck gets in and the spacings get messed with.

or

2)Turn the bike upside down and slowly turn the pedal by hand.

Look how the chain settles on the cassette - if the rear mech needs adjusting you should see the chain brushing the adjacent sprocket slightly and causing the noise that you have heard.

I'll try the advice offered and see what happens, the actual cassette did work loose many moons ago and I had to tighten it, and it seems ok, but there is no harm in trying again.

Have you tried adjusting the indexing of the gears? It's either adjusted by turning the barrel at the rear mech or via the screws located on the rear mech/derailleur itself.

If that doesn't sort it out - could possibly be the casette.

I've had a fiddle doing small incrememts, sometimes it works, but after a while it goes back to jumping again or it gets worse.

Forget all the previous advice Plax,just go and buy yourself a new bike
You know you want to.

Don't tempt me I'm trying to be good, although I have deperately been trying to avoid buying a winter hack off ebay......

 

[Plax]

Gears now working fine again, turned out it was something as simple as the cable tension on the rear mech after all. Fingers crossed it'll stay good.