loose chain?

rollingscone

Heard a strange jangling sound on the way home tonight and discovered that my front gear had slipped to the smallest cassette.

Even after I rectified this I can't pull the left pedal upward i.e. it doesn't engage and just drops back down.


Looking at the chain now there is the slightest bow at the top.

Is it likely to be something I can fix by removing a link?

doozerie

It sounds like your front mech isn't pushing the chain onto the large chainring properly, so your problem may be related to that rather than the chain itself (and could be an issue with the derailleur, simply not enough tension on the cable, maybe even a damaged or excessively worn outer chainring, etc.).

That said, maybe the chain itself is worn too and needs replacing but I wouldn't expect the symptom you are describing to be the first sign of that (the sag could be a sign of a badly worn chain or could be something more subtle like insufficient tenson in the spring of the rear mech). If the chain is worn then removing a link won't fix the problem.

Simplest and most reliable way to determine if the chain is worn is to measure it with a ruler as described in the "Measuring Wear" section of this page.

rollingscone

doozerie wrote: »

It sounds like your front mech isn't pushing the chain onto the large chainring properly, so your problem may be related to that rather than the chain itself (and could be an issue with the derailleur, simply not enough tension on the cable, maybe even a damaged or excessively worn outer chainring, etc.).

That said, maybe the chain itself is worn too and needs replacing but I wouldn't expect the symptom you are describing to be the first sign of that (the sag could be a sign of a badly worn chain or could be something more subtle like insufficient tenson in the spring of the rear mech). If the chain is worn then removing a link won't fix the problem.

Simplest and most reliable way to determine if the chain is worn is to measure it with a ruler as described in the "Measuring Wear" section of this page.

The entire mech/drivetrain was shockingly dry when I checked it this morning. I guess I should have known to give more TLC in this weather.

The rear mech needs enough force before unbending that the bike moved before the derailleur did. So I'm hoping that means it's ok.

Definitely some wear on the front cogs but not a huge amount.

Will measure properly this evening but seems like the chain is a tiny bit loose going by the pull test.

Any tips on how to assess the front mech for wear/problems?

doozerie

For the front mech, the first thing I'd check is if there is slack in the gear cable when the chain is on the smallest chainring. If so, then tensioning the cable might be all that is needed to ensure that the mech moves enough push the chain on to the outer chainring.

If there is no slack in the gear cable, then pull th cable (you can do this by hand if the inner cable is exposed along the top or down tubes, otherwise use the gear lever) and see if the outer plate of the front mech goes out beyond the teeth of the outer chainring. If not, then it may be the limit screw on the mech that is blocking it, or it may be an accumulation of dirt that is preventing it from moving enough. Adjusting the screw and/or cleaning and lubing the mech might be all that is needed in that case.

If the chain wasn't lubed then that would tend to make it more reluctant to move when pushed by the front mech, so cleaning and lubing the chain might solve the problem too (assuming it's not so worn that it needs replacing).

rollingscone

Just gave the chain some TLC before I left the house this AM.

Tried it now and it seems to be functioning as normal again.


I used to obsessively care for the commuter when I used it daily but I currently only use it two days a week and give all my non commuting love to my roadbike.

Thanks for the help Doozerie.