Clicking from chain but only in one gear

[rivers]

Hi all,
After a bit of advice. There is a bit of constant clicking coming from my chain, but only when I am in one specific gear (big cog in front, 4th sprocket in the back) Other than that, the chain is silent. Any ideas as to what can be causing it?
Thanks in advance

 

[Yellow Saddle]

Define constant. Is it rhythmic. Is it once per chainring revolution, once per chain revolution or once per wheel revolution?

Have you put the bike in a stand and hand-pedaled it in that gear with your ears and eyes searching for the source? This is much easier than a bunch of wild guesses.

 

[Ajax Bay]

Need to tweak the indexing which sounds as if it is 'just' a bit off.

 

[sight-pin]

It also could be the chain connector hitting the front derailleur if it's once every chain revolution.

 

[ufkacbln]

Chain's a bit slack?









(Someone had to......)

 

[davidphilips]

Hi all,
After a bit of advice. There is a bit of constant clicking coming from my chain, but only when I am in one specific gear (big cog in front, 4th sprocket in the back) Other than that, the chain is silent. Any ideas as to what can be causing it?
Thanks in advance

a few pictures may help with replies but have a good look and check theres nothing bent on back cassette ie one tooth slightly bent, easly to spot when turning pedals with bike on a stand or even upside down, also check chain for tight links.