chain skips

[DoubleLori]

If you put a brand new chain onto worn cassette or freewheel cogs, it will often skip. How many miles were on your cassette (or freewheel)? Chains need to be replaced BEFORE they elongate to more than 12-1/8 inches per 24 links or they will wear out the cogs. If the chain is replaced regularly before this point, the cogs will last much longer as they won't get misshapen by the too-long chain. If new chain on worn cogs is your situation, the only solution is to replace the cassette (or freewheel) with a new one.

[roadie gal]

Another possibility is that even a new chain may have a stiff link that will make it skip. Try putting the bike up and watching the chain go over the cogs as you spin the pedals. You may be able to see one link that doesn't bend as well. The best way to loosen it up is to put some lube on it and rock the link back and forth (across the way it is supposed to bend, not with it's normal bend). This may seem like you're going to break the chain, but you won't, and it works.

[angriecow]

:) just fought for 2 hrs with a brand new shimano 93 chain too... and that damn wiggle trick was SOOOO NOT working.
so i cheated :P, i used my chainbreaker to slowly (and i mean slowly) tighten the new pin in, and kept making sure the joint was super flexible. when i t came time to snap the lead off, if the link became stiff after than, i used the breaker on the reverse side to loosen it a smidge. takes time and patience, but it works
good luck.