Put a new chain on now its jumping up and down gears.

[Martyb32]

Help Guys,
Put a new Shimano Tiagra chain on my Merida cyclocross 300 I've not even done a 1000 miles on the bike but the old chain was a bit stretched.
On it this morning and the gears are jumping but only when its on the small cog at the front and the smaller ones at the back, what have I done wrong?

Cheers.

 

[ayceejay]

This is known as 'cross chaining' and the jumping is a way of telling you that you are doing something wrong, it is possibly the reason you wore the other chain so quickly too.

 

[Hip Priest]

Do you normally ride with that combination of front & rear cogs? If so, that would tend to rule out cross-chaining as the cause of the skipping. More likely that the teeth on the cassette are worn. Unusual after <1000 miles, but not impossible.

 

[Svendo]

I'm not clear if it's jumping side to side into different gears, or jumping forward over the teeth of a sprocket?

 

[Banjo]

More than likely the teeth on the cogs on the rear cassette are a bit worn and you may need a new cassett as well.

Sometimes a new chain will "bed in a bit" if you can put up with it for a few rides it may sort itself out.

 

[bikeman66]

How old is the cassette and the chainrings? A new chain and old cassette and rings will very likely struggle to mesh properly. Inspect them for wear and possibly take advice from your local bike shop. Agree with comments above though, regarding not using the big/big small/small combinations, although I'd be most inclined to think that the new chain needs pairing up with new rings and cassette from the symptoms you describe.

 

[Martyb32]

Thanks Guys,
Wouldn't really call it cross chaining as it does it on the 3rd smallest and jumps up to the 4th.
It didn't do it before I changed the chain, it did come with a KMC chain and I've put a shimano one on it.
Maybe give it a while see if it beds in if not i'll change the cassette.

 

[Martyb32]

How old is the cassette and the chainrings? A new chain and old cassette and rings will very likely struggle to mesh properly. Inspect them for wear and possibly take advice from your local bike shop. Agree with comments above though, regarding not using the big/big small/small combinations, although I'd be most inclined to think that the new chain needs pairing up with new rings and cassette from the symptoms you describe.

The bike and cassette has done less than a thousand miles, when I measured the chain the 0.75 fell straight through but the other end only went half way through.

 

[Banjo]

If its changing gears between 3d and 4th on its own you may just need to adjust the cable tension .When they jump due to worn cogs they don't usually change gear just bump a bit in the same gear if that makes sense.

 

[Tin Pot]

Thanks Guys,
Wouldn't really call it cross chaining as it does it on the 3rd smallest and jumps up to the 4th.
It didn't do it before I changed the chain, it did come with a KMC chain and I've put a shimano one on it.
Maybe give it a while see if it beds in if not i'll change the cassette.

I've had exactly the same problem this weekend (thread in this forum) 3rd and 4th. Also 1st and 2nd on steep gradients.

I'm going to play with the rear dérailleur tension tomorrow, but I have a new cassette on order - I reckon that is the likely cause for both of us.

 

[Martyb32]

I got home from my work and went to change the cassette but really don't think it's worn.

 

[Tin Pot]

I got home from my work and went to change the cassette but really don't think it's worn.

I'm no expert, but aren't those shark fins in the first pic, bottom left, largest sprocket?

 

[Martyb32]

I'm definitely no expert, think I'm going to give up and visit my LBS lol.

 

[themosquitoking]

I'm no expert, but aren't those shark fins in the first pic, bottom left, largest sprocket?

In that first picture it looks like more than just the largest sprocket, the next couple down also appear to have them but all in the same area of the cassette. Possible problem with the wheel bearings or something maybe?

 

[Martyb32]

I'm a happy man
Solved my problem after changing the cassette it was still the same, put on the old chain and it was great. On further inspection the quick link I was using on the new chain must be for a 8 speed. Put the old cassette back on, new chain with old link and we're in business.
Feel a bit silly but as I say to everyone every days a school day.