Slipping chain?

If it's a freewheel check that it is not slipping usually you will get a loud crack as it happens.
If general wear on the chain gear teeth and chainring it will not usually cure the problem by changing one component such as the chain or chainring and could make things even worse.
If all parts look worn and you can confirm this by comparing to new parts for shape then you must replace all parts to be sure.
If the teeth are worn they will have a sharp point on them (both gears and chainring) if the chain is worn you will be able to flex it sideways quite easily. A new chain will feel tight if flexed sideways.

Geoff L
December 2008

If single speed probably chain too slack or freewheel ratchet is slipping
If derailleur type gears then could be, in order of likelihood:
1. chain / sprockets worn - chain stretches and does not fit into gap between sprocket teeth correctly. Bike shop has a tool to check this (tool approx. 10 quid)
2. gears not adjusted - not difficult but u need to readup on it first. If in doubt try a little more cable tension by unscrewing cable adjuster on rear derailleur about half a turn anticlockwise
3. freewheel ratchet slipping - probably new freewheel or some good ones can be cleaned out which normally fixes it.

Should have started with - GIVE IT ALL A THOROUGH CLEAN, CLEAN OR REPLACE INNER CABLES, AND CHECK CHAIN STRETCH

Andrew D
October 2008

its not the cogs at the back is the problem ,if you look at the chainrings the ones at the front" were the peddels are" take the chain off and look at them ,if the teeth are worn out , they will look like sharksfins" point backwards" so the chain dont have anything to grip on , and when you go up a hill or put pressure on them ,it wil slip, its known as (chain jumps) you can just replace the worn out ring , the ring comes apart allen keys" ill check back here if you need to know more, mick

mick
August 2008