Chain comes off when peddling backwards

roverthehill

Hi,
A bit of a newbie so apologies if a basic question!!

Having some probs with my new(ish) bike. Today, the chain can't falling off when I peddled backwards, even a half turn backwards causes issues. Particularly problematic when in the low gear at the front and high gear at the back. In fact, even peddling forwards was an issue when in the low gear in the front (bottom) and high gear at back (bottom). The chain looks a little grubby so I'm degreasing it good and proper this avo. A few weeks ago, I adjusted the cable tension on the rear derailer - could that have an effect too?

Basically the chain looks to be really loose when in certain gears.

Any advice would be appreciated.

Greer_

Sounds like the chain is to big - you probably need to buy a chain tool and an appropriate chain link (depending on make of chain) and remove a few links.

e.g. http://www.wiggle.co.uk/kmc-9-speed-cha ... hain_Links
and http://www.wiggle.co.uk/park-tools-chai ... hain-tool/

may not be right depending on chain speed (7/8/9/10)

Need further info on chain

roverthehill

Not too sure about the chain - the markings are: narrow, KMO, 2 and has a power-link

Cheers Greer, ps from belfast:)

warpcow

roverthehill wrote:

when in the low gear in the front (bottom) and high gear at back (bottom)

This is likely to be your main issue. There's no reason to be in that combination, since it's replicated elsewhere, and the chain becomes too slack.

Was it working ok before you fiddled with the cable?

roverthehill

it was fine before fiddling - but the gears weren't shifting smoothly so I adjusted the tension. After that, I've been out a few times and had no real issues until 2day.

The Northern Monkey

Don't pedal backwards?

roverthehill

lol. It even happens when you turn the peddle backwards to get in position to start cycling. In addition, even when in the low gear at front and high gear at back, the chain starts playing up and getting caught. I'd never really be in this gear but it never used to do this before so I'd like to fix it

felix.london

Are you sure that soppy, plastic circular thing that is meant to stop the rear mech hitting the spokes hasn't fallen to bits and is jamming up the freewheel?

roverthehill

Took the chain off and thoroughly degreased and dried it. To be honest that's the 1st time I'm taken it off to clean - usually just try and clean it whilst on the bike.

Seems to have more or less done the trick. Amazing what a good clean does!

Greer_

The Northern Monkey wrote:

Don't pedal backwards?

I was thinking that

roverthehill wrote:

Took the chain off and thoroughly degreased and dried it. To be honest that's the 1st time I'm taken it off to clean - usually just try and clean it whilst on the bike.

Seems to have more or less done the trick. Amazing what a good clean does!

Greer_

Oh and where do you usually ride? I'm from bangor but go up there the odd time. I usually do the sunday run trails (thats not the only time you can do them! Just the general name!) from helens tower to crawfordsburn