Noisy, sucky front chainring on new chain

[Snoozeboy]

I recently changed to my 3rd chain on the original bosch drivetrain (16 tooth front, 11-46 shimano xt rear).

It now makes a loud clicking noise when under load and I've noticed the bottom "row" of the chain vibrating up and down a lot in time with the clicks. Occasionally, I now also get chain suck when under extreme load, whereas I didn't before. The chainwheels were cleaned thoroughly when I replaced the chain.

Would I be right in assuming my front chainring is worn and needs replacing? It doesn't make sense to me that a worn chainring should be sucky. Surely it should be slippy? I've not noticed any slipping yet on either the front or the rear. To try to solve it I've dumped a load of wet lube on the chain, in case the new chain is just a bit stiff.

It's also possible that it's due to a different problem - I took the trouble to clean and straighten the rear mech cage and jockey wheels, so it's possible the chain is fouling somewhere there, if I've managed to unstraighten the cage.

Thanks in advance for any advice.

 

[paquo]

yes, install new steel ring

 

[steve_sordy]

Front rings wear just the same as cassettes. Even faster now that there is mostly only one of them to share the miles! Have a look at the pic below to compare your front ring. The new one is at the back!

Normally it is the hook shape on the teeth that clings on to the chain, but burrs can do that as well. The burrs are created by chain pressure and will definitely contribute to chain suck by catching on the sideplates. As a possible quick and temporary fix (one ride), you could file off the burrs. That should allow time to buy a replacement ring.

 

[Snoozeboy]

I'm thinking of going to the pds tomorrow to make a last tour before the end of the season.

To shut the chain up I think I'll change back to my old chain until I get a new front chain ring delivered.

Also, then I'll know for sure that it's not just a problem with the cage.

Having been persuaded to the idea of 3 chains per cassette, I'm right back thinking to one chain per cassette and change the lot at the same time, at the point of failure. Each time I've changed the chain, it hasn't gone too well and it just seems that new and old don't go together like old and old.

 

[Snoozeboy]

Finally changed the front chain ring and the new chain is fine again.

(I think my cassette is due for a change however, as it's looking quite shark toothy and I noticed a couple of slips today, albeit in low (easy to turn) gear).