Clicking noise caused by chain / jockey wheel issue

jjsh

I've just built a bike, and am having a problem where the chain, as it approaches the lower jockey wheel, appears to be slightly out of line with it, so it sort of 'clicks' as it engages. Either the chain is too far over towards the chain stay, or the lower jockey wheel is to far over towards the spokes (sorry, I'm really struggling to make this clear), or both I suppose, but anyway it causes the aforementioned clicking that can't be good.. Apart from this, the bike shifts up and down without issue, both front and back smoothly, doesn't drop chains anywhere when shifting, if the rear gear cable is totally released, it drops to the smallest cog and stops, I.e. doesn't drop, suggesting the limit screw is right, and so on. It's a brand new hanger which I aligned after fitting with the proper tool (first time I've done this, however, so I'm wondering if I've ballsed this up). The rear mech comes from one of my working bikes that I'm sure wasn't doing this, so am hoping it isn't bent.

It is worse in big front / somewhere in the middle at the rear than big front / small rear, but only very very slightly. It basically does in all gears.

Any ideas where to look next. I haven't built a bike for over a year so I've got a horrible feeling I've missed something obvious. Thanks for any help!

AK_jnr

Mine was clicking on a jockey wheel. It was a dodgy quick link. Changed to a new one and the problem was sorted.

jjsh

Was yours clicking on every link or just the quick link?one does in on every link, but its worth a try I'll go and check the quick link is closed properly. Cheers.

Secteur

Upper jockey wheel ok?

If so - bent mech cage, throwing the lower jockey wheel a fraction of a mm out of line with the upper jockey wheel.

Can't think of anything else from your description, though of course it's very hard to guess.

ElectronShepherd

If it clicks on every link, is the chain threaded through the rear derailleur correctly? There's two little metal tabs that are bent across from the long cage arm, and it's easy to wrap the chain over one or both of those, instead of passing under them.

jjsh

Secteur wrote:

Upper jockey wheel ok?

If so - bent mech cage, throwing the lower jockey wheel a fraction of a mm out of line with the upper jockey wheel.

Can't think of anything else from your description, though of course it's very hard to guess.

I've just had a look, and its hard to tell, but it does look like the same is happening where the chain exits the rear mech from the upper jockey wheel, only not was bad (or so it looks like to me). Does this suggest its the derailleur hanger alignment?

jjsh

ElectronShepherd wrote:

If it clicks on every link, is the chain threaded through the rear derailleur correctly? There's two little metal tabs that are bent across from the long cage arm, and it's easy to wrap the chain over one or both of those, instead of passing under them.

I;ve checked this again, and its threaded through correctly, but thanks for the suggestion.

6wheels

More than likely the hanger, the alignment tool is cheapish.

AK_jnr

Ah mine was only clicking on that one link so clicking once every two pedal revs.
I assume then jockey wheels themselves arent loose?

jjsh

Today is the first chance I've had to look at this again, so I removed the rear mech and had another go with the hanger alignment tool. The hanger was way off ~ I've no idea how I managed to miss that. Anyhow, a bit of bending with the alignment tool later, and all is well after a re-index, so thanks for all the help and encouragement folks.

I find using the alignment tool quite alarming, I keep thinking something is going to go 'snap!'.