Chain replaced but bottom jockey wheel "jumps"? I have a 10speed MTB and replace the chain using a powerlink.  Now the bottom pulley wheel makes like a jumping kind of movement.  It is not smooth.  Also when in my small ring in front I get chain suck.  It sucks!! I never get chain suck :(
The jumping is either chain friction (ie the links are not moving smoothly against each other) or links catching on teeth.

Fagan.co.za has a useful article on chain suck.

To summarise his points, the most common causes of chain suck are:


Mud causing extra friction
New chain with a worn chain ring
Worn chain with a worn chain ring
Worn chain with a new chain ring


Because the chain loads up unevenly on teeth on the bottom of the chain ring you get high friction, and the chain won't disengage properly from the teeth.

First up - clean your chain and lubricate it properly.

If the problem continues, the simplest fix is to replace the chain ring, but you could also get your teeth reprofiled to reduce the friction.