V-20 Rear Derailleur Problem

[Rick Moore]

On my V-20 10 speed, when the chain is on the 11 cog (Highest gear), and I’m in the small chainring, the chain is rolling off the side of the bottom pulley of the rear derailleur and locking the chain in the cage.

The rear derailleur and hanger are two years old and they have 12,000 miles on them The derailleur is a SRAM MB GX type 2.1 long cage. It is connected to the derailleur hanger that I bought two years ago. When it started doing it, I replaced the chain, and it’s still doing it.

With 12000 miles on it, is it time to replace the hanger? The whole derailleur? Or replace the pulleys— I can’t find any for that model so will others fit?

Would appreciate any help. Thanks

 

[cpml123]

I don't much much about derailleur, but 12k mi sounds really good to me! I just recently changed the V20 derailleur from Rival to GX 2.1 to match my S40 set up. The GX derailleur is in stock again for about $70. You might as well change it since it's not too expensive.

 

[Andrew Wilson]

Not sure what your problem would be without putting hands on it but 2 years and 12k miles is nothing for a maintained and not crashed RD. I’m sure I have more than that on mine with zero issues. I bet the one on my Cervelo is 8-10 years old with tons on mileage on it. You should probably let a shop that can check hanger alignment before you start throwing parts at it.

 

[ReklinedRider]

Is the chain rolling off the bottom pulley to the outside or to the inside?

 

[Andrew Wilson]

Oh... and @Rick Moore , We missed you at the SR local games last Sunday. We could have gone to my shop and checked it out.

 

[Rick Moore]

Is the chain rolling off the bottom pulley to the outside or to the inside?

Inside.

 

[Rick Moore]

Oh... and @Rick Moore , We missed you at the SR local games last Sunday. We could have gone to my shop and checked it out.

I didn’t go cause the distance is just to short for me….

 

[Andrew Wilson]

I didn’t go cause the distance is just to short for me….

You animal. Remember us little guys as you progress. FYI. I had an issue with shifting on my Cervelo that was solved with a manual adjustment of the replaceable derailleur hanger. I still suggest you have this checked. Don’t trust just replacing the hanger. Another thing to check is chain length. If it’s too long there might not be enough tension when on the 11 cog.

 

[LarryOz]

Rick,
You get a real extreme chain angle going from little cog to little ring. Ideally as you start moving down the cassette from large to small, about mid-way you should shift into the large ring to take advantage of it instead of just going on down to the smallest cog. You probably just have a very slight adjustment problem. But as I said you can avoid your problem by never going small/small.
12K miles is also nothing for a decent derailleur. I have been riding my V20 for 5 years and have over 100,000 miles on the same derailleur with no issues.

 

[Beano]

Sounds to me like there is some play in the jockey wheel, is there some side to side movement? If so maybe that the jockey wheel needs replacing.

 

[Rick Moore]

Rick,
You get a real extreme chain angle going from little cog to little ring. Ideally as you start moving down the cassette from large to small, about mid-way you should shift into the large ring to take advantage of it instead of just going on down to the smallest cog. You probably just have a very slight adjustment problem. But as I said you can avoid your problem by never going small/small.
12K miles is also nothing for a decent derailleur. I have been riding my V20 for 5 years and have over 100,000 miles on the same derailleur with no issues.

Thanks that’s reassuring about the derailleur. And yeah I understand about staying out of small chainring/large gear combo and I do avoid that. However for 12,000 miles it was not a problem. Now it is. I’m just wondering why. BTW: I always shift to the small chainring and highest gear at the end of my ride to save wear and tear on the cables, and then put the bike on my work stand. Then before I ride I spin it up to get my power pedals activated. That’s when it’s happening.

 

[Randyc3]

I like @Beano’s idea. If you have some spare jockey wheels, install them as a test. As mentioned above would have your LBS check out derailleur hanger alignment or you could do it to if you have a park tools DAG 2.2. Good luck and let us know how it goes.

 

[Beano]

Put in the low gear, get someone to lift the bike up and turn the pedals, you're are looking for any side to side movement in the jockey wheel.

Funnily enough I had this problem on my DF bike when I put it on the trainer a few weeks ago, the chain was getting sucked and then it would come off. Got off and had a look and the tension jockey was not running true, took the mech off, replaced the jockey wheel and now it's fine.

FWIW this mech was seven years old and was part of my commuting bike that I go to work on in all weathers. I put it down to overall wear and tear.

EDIT: And just checking but the chain is routed correctly through the guides on the cage? As an aside this can lead to noise in certain gears when out doing a test ride.....

Could also make the chain come off.

 

[Rick Moore]

Thanks everyone. I’ve decided to take Larry’s advice and stay out of the small chainring 11 cog on the cassette.

 

[Rick Moore]

Finally figured out the problem. Changed out rear derailleur hanger and the problem is gone. When I compared my old hanger with the new one I could see where the old one was slightly bent. Thanks for your input.

 

[Andrew Wilson]

Hmmm, I remember hearing checking hanger alignment somewhere . Shame you didn’t come to the local sr games. I could have put it in my stand and used my hanger alignment tool to check and adjust for you . Have no fear, I’m an Engineer.

 

[Michael Fasher]

On my V-20 10 speed, when the chain is on the 11 cog (Highest gear), and I’m in the small chainring, the chain is rolling off the side of the bottom pulley of the rear derailleur and locking the chain in the cage.

The rear derailleur and hanger are two years old and they have 12,000 miles on them The derailleur is a SRAM MB GX type 2.1 long cage. It is connected to the derailleur hanger that I bought two years ago. When it started doing it, I replaced the chain, and it’s still doing it.

With 12000 miles on it, is it time to replace the hanger? The whole derailleur? Or replace the pulleys— I can’t find any for that model so will others fit?

Would appreciate any help. Thanks

Straiten the derailleur hanger, plenty of companies make a tool to do it. Check out Wolftooth components hanger straightening tool.