Chain slipping - possible causes?

Dermot Illogical

I've spent so much time worrying about/dealing with punctures that my chain has been ignored, and now it's letting me know. Every now and then it slips, usually while on the middle ring and in one of the more central gears on the cassette. It 1st happened last week and tends to maybe happen once a day/every 2nd day. Usually it's when I start spinning again after a period of freewheeling and it gives a little slip and drops a gear.
What should I be looking to check/adjust/replace?
Is the chain possibly on the way out, or might I just need to adjust derailleurs?
The bike is new-ish and has about 3,200km on it.
All advice welcome.

ashleey

Could be chain stretch and now worn teeth on most frequently used cogs. Hopefully though it is just stretched cables through use requiring adjusting the rear derailleur barrel adjuster. Put the bike up and pedal by hand and go through the gears. Turn the adjuster until no more clicking slipping or phantom gear changes occur. Check out the park tools website for full details. Good luck

Lashed

Chances are your chain and cassette need replacing.
Some people say at least the chain should be replaced every 2000k or so and cassette for every 3 chains. Signifigant wear can be expected any time after this.
If the cause of slippage is due to chain wear then the cassette will be too far gone for a new chain to run on it. Thats why both need to be replaced.

Dermot Illogical

Thanks for the answers. Hopefully it's not worn, but if it is can I do any worthwhile upgrades while replacing?

Bike is a Ridley Eos
Cassette is Shimano Tiagra 9s 12/25
Chain is KMC X9SL

CardBordWindow

I had a similar issue not too long ago, and the culprit was that the front rings had been slightly dented. When I put pressure on by standing up/uphill cycling, the chain would slip down. Very inconvenient!

Lashed

RT66 wrote: »

Can I do any worthwhile upgrades while replacing?

Bike is a Ridley Eos
Cassette is Shimano Tiagra 9s 12/25
Chain is KMC X9SL

I would suggest these 2:
http://www.wiggle.co.uk/sram-pc991-9-speed-chain-crossstep/
http://www.wiggle.co.uk/sram-pg950-9-speed-cassette/

ashleey

The tiagra cassette is fine to reorder but I would consider a different chain. I changed mine to a wipperman 9 speed recently and my tiagra set up is like silk now. Either way a chain with a powerlink type connector is well worth looking at

f1000

Similar problem myself... chain seemed to be slipping the became more regular until I was in the middle of a busy junction spinning like a lune & going nowhere!

Freehub = bollixed. http://www.parktool.com/blog/repair-help/freehub-service.

Left the wheel in yesterday and will have it back on Fri

Dermot Illogical

Update: Went to LBS who say it all looks fine. No excessive wear that they can see and that gears are shifting smoothly. Will keep an eye on it.

Of course Murphy's law struck and I punctured on the way home.