Really irritating rattle!

C3PO

My training bike has developed a really annoying rattle from around the rear dérailleur! Only on bumpy roads and seems to be worse in the small front ring/smaller rear combinations! I thought it was a loose cassette but it seems to be fine! One of the jockey wheels seems a bit loose laterally but that would hardly cause such a loud rattle? Any thought?

Plastik

Chain rattling off cage?

Hmmzis

Chain as sugested above migh be one cause. The derailer tensioning spring might not be tight enough for the small front small rear combination. There is a little screw there that tensions the derailer/chain.

OEMBS

Sounds like the tensioner spring in the rear mech, when the gears are in small ring/lower gears the cage rubs off the chain. You may notice a slack chain, the mech dosnt snap back as it should. Thats what it was on my bike, I just fired on a new mech and chain sorted.

C3PO

OEMBS wrote: »

..... I just fired on a new mech and chain sorted.

Hmmm .... don't really fancy "firing on" a new Dura Ace mech unless I really have to!

OEMBS

Lol, i know what ya mean.
New spring is easy sorted tho..

MediaMan

Worth double-checking the cassette. I had a rattle, checked the cassette and it seemed fine. Checked the whole bike over, and only solved the problem a couple of weeks later when the cassette loosened a bit more and it became obvious.

In my case the shifting got a bit sloppy as well, presumably due to the loose sprockets moving relative to the wheel as they took up the tension as well as them being a bit out of alignment for optimal shifting.

May well not be your problem, but definitely worth a double check!

camaghead

It could be that the chain is too long (by a link or two) combined with chain wear. The Dura Ace chains wear out quickly - particulary if you cross chain.

I'd check the chain for wear, then check the number of links using Parks formula. If its being doing it for a while the cassette might be worn aswell.

DisasterIRL

This may seem stupid but are you sure it's not the chain knocking off the frame?

C3PO

camaghead wrote: »

It could be that the chain is too long (by a link or two) combined with chain wear.

I think you might be right!
When I look at the bike on a stand when it's in the small front/smaller rear combos the chain is very close to the cage. I can remove a link and still be ok for big/big (not that I would ever use that combination of course! :rolleyes:).
Also suspect that I need to "Man Up" and change into the big ring sooner!

07Lapierre

C3PO wrote: »

I think you might be right!
When I look at the bike on a stand when it's in the small front/smaller rear combos the chain is very close to the cage. I can remove a link and still be ok for big/big (not that I would ever use that combination of course! :rolleyes:).
Also suspect that I need to "Man Up" and change into the big ring sooner!

If the chain is hitting the chainstay, there should be scratches/chipped marks on the top of the chainstay.

A good use for old inner tubes, cut them into strips and use zip-ties to attach a strip to the top of the chainstay. Protects the frame and reduces rattle noises.

C3PO

07Lapierre wrote: »

If the chain is hitting the chainstay, there should be scratches/chipped marks on the top of the chainstay.

A good use for old inner tubes, cut them into strips and use zip-ties to attach a strip to the top of the chainstay. Protects the frame and reduces rattle noises.

No not hitting the chainstay .... seems to be hitting the bottom of the mech cage!

Thanks for all the suggestions!

DirkVoodoo

C3PO wrote: »

One of the jockey wheels seems a bit loose laterally but that would hardly cause such a loud rattle? Any thought?

Just for future reference, the upper wheel acts as a guide and is supposed to have a small amount of lateral play to function correctly. Shifting wouldn't be as smooth otherwise.

C3PO

DirkVoodoo wrote: »

Just for future reference, the upper wheel acts as a guide and is supposed to have a small amount of lateral play to function correctly. Shifting wouldn't be as smooth otherwise.

Yes I understand that but this one seems to be a bit "looser" than usual!

C3PO

Well my initial guess actually proved to be correct! Even though the cassette felt tight it still seemed to be the most likely culprit. I then remembered that when I changed the cassette recently I didn't use the supplied Shimano spacer because the original cassette didn't have one (new and old cassettes were both 105s) and there was already a spacer on the Askium rear wheel! Anyway stuck it in .... tightened things up .... problem solved!
120kms around the Wicklow Peaks today .... not a rattle to be heard ..... A fair bit of wheezing though!