i have a mountain bike and have just replaced the chain for new. now i have a new problem that the chain keeps slipping on the back cassett or gears, i have tried to shorten the chain and extend it but it keeps on slipping.the bike is a specialized mountain bike with 8 cogs on the back cassett and the standard 3 cogs on the pedles, any surgesstions chaps, cheers, pin

pin, March 2007

spring on chain tensioner too slack. tighten or replace the CT

Richard, March 2009

Adjusting the chain length will not help your problem. The rear derailleur is used to take up the chain slack and keep the right tension on. What you need to adjust is the derailleur. The two small adustment screws on the rear derailleury move the derailleur pulley into position under the the cassette rings and set the inner and outer limits. Much too lengthy a discussion to go into detail here but go to www.sheldonbrown.com for repair help. It is the bible for many beginning mechanics.

Ross, June 2007

When you replace the cassette you need to replace the chain too, or vice-versa.
This is because the sprockets and chain both wear down together and mesh with each other.

Big Softy, March 2007