Jocky wheel dropping the chain?

[LEX]

G'day guys, just after a bit of trouble shooting. My lower jocky wheel keeps dropping the chain between the when and cage. What could be the cause?


-2010 SRAM XX on a 2010 superfly
-checked the cage is done up tight
-doesn't look twisted by sight.

Cheers

 

[Shredden]

Have you replaced the jockey wheels since 2010?

3 years is a long time for jockey wheels.

 

[Chil]

I take it that it happens under load?
It might be the freewheel slipping on the rear wheel not the chain itself, do you have another rear wheel to try out?

 

[frensham]

G'day guys, just after a bit of trouble shooting. My lower jocky wheel keeps dropping the chain between the when and cage. What could be the cause?


-2010 SRAM XX on a 2010 superfly
-checked the cage is done up tight
-doesn't look twisted by sight.

Cheers

Between the what and cage?
Dropping the chain means that it is coming off. It is not possible to 'drop' a chain at the jockey wheel (assuming the chain is correctly routed through the rear derailleur). Is the problem you are referring to perhaps a skipping of the chain off the cassette cogs?
Worn jockey wheels (they become very pointy) will only affect shifting, they are not under any real load.
I won't ask you how old your drivetrain is, because this is irrelevant. How many kilometres has your drivetrain done? Has it bee maintained/cleaned regularly? I suspect it could just be a worn cassette, chain and chainwheels.

 

[Halo1]

G'day guys, just after a bit of trouble shooting. My lower jocky wheel keeps dropping the chain between the when and cage. What could be the cause?


-2010 SRAM XX on a 2010 superfly
-checked the cage is done up tight
-doesn't look twisted by sight.

Cheers

I had a a similar problem where the Jockey wheel was not spinning freely. The extra tension on the chain would make it jump. I replaced the Jockey wheel after much (tight arse) deliberation and problem solved.

 

[silentbutdeadly]

The problem described can also happen if your chain is too long...not enough chain tension in the smaller chainwheels.

 

[Mywifesirrational]

Had this problem with an XT drive train (1x9), only happen in two largest cogs on the cluster. Turned out for me that my chain line was the problem used a few spacers to shift the front ring across solved it.

The went to a 2x9 setup, problem resurfaced, put a short med cage derailleur instead of long cage on and this also solved it.

Worth also making sure your hanger is not bent and anything else obvious like that.

 

[MARKL]

Personally with frensham, post a couple of pictures and you will get a better diagnosis.

 

[LEX]

That's what it looks like when it drops. The chain, cassette and chainrings are all pretty new. But I havnt changed the jockys wheels since I got it. But then again I don't ride heaps.

 

[MJS]

I'd start by taking a couple of links off that chain, you could probably use more tension judging by that pic.

 

[The Duckmeister]

Have your derailleur alignment checked. A munted derailleur that's pointing at a different angle to the chainline will do that.

 

[John U]

I had an xo carbon cage with a similar problem. Had trouble working out what it was. The back plate of the Carbon derailluer cage had cracked and would deform when I was going for a lower (larger) gear on the back. The chain would get stuck between the jockey wheel and the cage and when I pedalled would've folded the derailluer if I hadn't picked it up in time.

This would occur even though everything else was ok with my drivetrain.

It was caused by a bent derailleur hanger/way too much mud on my tyresWhich folded the derailleur in. When this occurred the derailleur appeared ok and was serviceable in most circumstances. It was a patch up job mid odyssey a was ok for the rest of the race.

To the op, check the back plate on your derailleur cage. I am guessing it might be fucked. I don't think carbon is the best material for dérailleur cages.