Chain jumping on middle ring

[trackdemon]

As per the title really Been using my Gary Fisher irregularly this year, not been serviced once (its well overdue!) and last time out I noticed it was jumping when standing on the pedals. Seemed to go away on the big ring - but I use middle ring most of all. Gears are adjusted OK, I think the problem might be down to chain wear which has caused a few teeth to break on the middle ring. Sound plausible?

I guess simple solution is new chain & ring if so.....

[budgie smuggler]

Probably just worn the teeth rather than broken them.

Replace the chain and middle ring. You might then find you need to replace the cassette also if it is too worn to mesh with the new chain.

[Floor Tom]

Almost certainly need new chain, cassette and middle ring. If you have worn the chain and middle ring out then the cassette won't be far behind and worth changing anyway. A skip in your drivetrain at just the wrong moment can be a really nasty expecience.

[trackdemon]

Floor Tom said:

A skip in your drivetrain at just the wrong moment can be a really nasty expecience.

Almost had a chalfonts > top tube interface. Not pleasant.

[anonymous-user]

merlin have a deore v-brake groupset on offer at the moment for £210. by the time you have bought a replacement cassette (£30), chain (£20) and a middle ring (£20) you may as well get this and have new brakes, shifters, mechs and a bottom bracket too....

the deore disc brake set up is £250.

you might think that its either not worth the cash or a step down if you are currently running slx or xt but technology has been filtering down and i would say that in terms of durability and function, deore now is as good as slx was a few years back. yes it might weigh a bit more than those mentioned but a new groupet will transform the bike.

[S1_RS]

trackdemon said:

Almost had a chalfonts > top tube interface. Not pleasant.

Surely you mean your Jacobs? Unless you suffer from piles?

[shouldbworking]

Could go crazy and actually look at the chainrings etc to see the problem?

[Gizmo!]

S1_RS said:

trackdemon said:

Almost had a chalfonts > top tube interface. Not pleasant.

Surely you mean your Jacobs? Unless you suffer from piles?

I actually did have a Davinas > top tube interface a few weeks back when (hybrid tyres + beech nut husks on a trail + steep hill != traction).

Stung a bit.

[shalmaneser]

Floor Tom said:

Almost certainly need new chain, cassette and middle ring. If you have worn the chain and middle ring out then the cassette won't be far behind and worth changing anyway. A skip in your drivetrain at just the wrong moment can be a really nasty expecience.

This. I'd be expecting to replace the whole lot.

Chainrings are expensive, you might find it worth upgrading to a hollowtech crank for not much more if you're not running hollowtech already. Much much stiffer than square taper and longer lived than ISIS.