Chain jumping problems

[joe90andabit]

Hi all,

Wondering if anybody can give any tips. I have a mountain bike ( or rather a bike that's half road half mountain ) and I'm currently getting chain jumping problems in the top two gears.
A few days ago the chain came off as I was changing gear and got caught between the frame and the back wheel, I managed to get it free pretty easily but after that the jumping started. I've tried adjusting the gears slightly and have looked for damage to the block on the rear wheel but all the teeth still look either ok or only slightly worn, the derailleur seems ok as well. When I'm adjusting it in the shed it seems to operate fine but as soon as you get out on the road and give the chain just a bit of welly it won't work properly.
It's not a brand new bike but its not that old either.
What is likely to be the problem ?

 

[boudreaux]

Hi all,

Wondering if anybody can give any tips. I have a mountain bike ( or rather a bike that's half road half mountain ) and I'm currently getting chain jumping problems in the top two gears.
A few days ago the chain came off as I was changing gear and got caught between the frame and the back wheel, I managed to get it free pretty easily but after that the jumping started. I've tried adjusting the gears slightly and have looked for damage to the block on the rear wheel but all the teeth still look either ok or only slightly worn, the derailleur seems ok as well. When I'm adjusting it in the shed it seems to operate fine but as soon as you get out on the road and give the chain just a bit of welly it won't work properly.
It's not a brand new bike but its not that old either.
What is likely to be the problem ?

Do you suppose maybe you hosed the chan or bent some cog teeth?

 

[joe90andabit]

Do you suppose maybe you hosed the chan or bent some cog teeth?

Possible I guess, I'll have a closer look and see how the teeth are and check the chain.

Thanks.

 

[RC2]

...When I'm adjusting it in the shed it seems to operate fine but as soon as you get out on the road and give the chain just a bit of welly it won't work properly...

On a stand in the 'shed' is fine make derailleur adjustments to get in them in the right neighborhood, but know you may need to tweak them on the next ride. If this doesn't work: what boudreaux said.

 

[Cryoplasm]

I too have the same.

I have turned my Trek MTB into an ATB - half road/mountain.

My chain has started jumping a little too.

I think you need to look at your chain. Has probably become stretched from over use. Need to install a new chain.

 

[boudreaux]

I too have the same.

I have turned my Trek MTB into an ATB - half road/mountain.

My chain has started jumping a little too.

I think you need to look at your chain. Has probably become stretched from over use. Need to install a new chain.

And a badly worn chain will trash the cassette too.....But, sometimes, a jumping chain is dreailer cable tension, among other things.

 

[daveornee]

Hi all,

Wondering if anybody can give any tips. I have a mountain bike ( or rather a bike that's half road half mountain ) and I'm currently getting chain jumping problems in the top two gears.
A few days ago the chain came off as I was changing gear and got caught between the frame and the back wheel, I managed to get it free pretty easily but after that the jumping started. I've tried adjusting the gears slightly and have looked for damage to the block on the rear wheel but all the teeth still look either ok or only slightly worn, the derailleur seems ok as well. When I'm adjusting it in the shed it seems to operate fine but as soon as you get out on the road and give the chain just a bit of welly it won't work properly.
It's not a brand new bike but its not that old either.
What is likely to be the problem ?

Start by measuring the chain. If it is 12 - 1/16 or more, get a new chain.
For further information and illustrations:
http://sheldonbrown.com/chains.html

Could we get an American English translation of "just a bit of welly"?

I have traveled to that side of "the pond" and enjoy learning more English.

 

[punkerfinger]

Start by measuring the chain. If it is 12 - 1/16 or more, get a new chain.
For further information and illustrations:
http://sheldonbrown.com/chains.html

Could we get an American English translation of "just a bit of welly"?

I have traveled to that side of "the pond" and enjoy learning more English.

The fact that this started happening after the chain came off and got stuck between the frame and sprockets makes me think the most likely thing is a twisted link in your chain. Something similar happened to a friend recently and it's something I run into at the shop fairly frequently. It will work alright in the stand because there's not a big load, however it is noticeable when you're riding because of the increased stress on the drivetrain. the fix will be a new chain, or at the very least, replacing the twisted links.

 

[joe90andabit]

Start by measuring the chain. If it is 12 - 1/16 or more, get a new chain.
For further information and illustrations:
http://sheldonbrown.com/chains.html

Could we get an American English translation of "just a bit of welly"?

I have traveled to that side of "the pond" and enjoy learning more English.

Actually Dave I've just tried replacing the chain because I thought the old one looked a bit twisted as it moved, I initially set the new one to the same length but the jumping still occurred so I've shortened it a bit but I'm still getting the problem, maybe I need to align the derailleur more accurate or the cogs on my block are worn.

On the topic of the term welly I guess its another way of describing force or pressure.

 

[joe90andabit]

Start by measuring the chain. If it is 12 - 1/16 or more, get a new chain.
For further information and illustrations:
http://sheldonbrown.com/chains.html

Could we get an American English translation of "just a bit of welly"?

I have traveled to that side of "the pond" and enjoy learning more English.

Actually Dave I've just tried replacing the chain because I thought the old one looked a bit twisted as it moved, I initially set the new one to the same length but the jumping still occurred so I've shortened it a bit but I'm still getting the problem, maybe I need to align the derailleur more accurate or the cogs on my block are worn. I've heard it said that whenever a chain or a block is replaced its a good idea to replace both at the same time.

On the topic of the term welly I guess its another way of describing force or pressure.