I was out riding my newly built bike and this happened during my ride. The chain somehow ended up on the outside of the guide pin of the derailleur cage! Yes I'm sure it was routed correctly before. As soon as it happened the bike was incredibly loud so I knew to stop. It happened when changing up for a climb. For reference this is a Dura Ace rd-9000 derailleur.
The cage is made of carbon and is flexible enough that I managed to get the chain back inside. Obviously something related to it's flexibility caused the issue but I'm wondering if I did something wrong and or this is a known problem I need to be worried about?
by Comfortable_Survey92
20 Comments
Chain’s too short
Are you sure it was routed correctly? Unless you are David Blaine, it should be physically impossible for it to end up that way otherwise.
If you’re sure you had it routed correctly I’ll believe you, but strange things happen:
https://www.reddit.com/r/bikewrench/s/xuNWxp0Z5f
That seems impossible. I have never heard of this happening, It must have been incorrectly routed,
I can’t even imagine how it manage to force itself outwards when the tension is pulling it inwards. Try to do the climb again and if the issue persists, consult a bike doctor.
Uh this is a shit post right?
Occam’s razor suggests it was installed improperly, which I have seen many, many times, even to the point of wearing deep groves into the tab.
Otoh I’ve never seen one end up that way from just riding.
Yeah chain on wrong side
Yes
I am aware of multiple instances of this being reported and have observed this occur at least a couple times on group rides.
I would refer back to the fact you were able to correct this without removing the jockey wheel just by flexing the cage. That’s exactly what causes this: chain stress / tension that flexes the derailleur cage.
In your case, I think this may have been exacerbated by the fact that your chain is too short and that carbon cage is flexible *and* maxed out.
Solution: add a link (or two?) and avoid cross-chaining. Shifting to the largest cog while remaining in the big chainring is gonna flex your derailleur cage and will likely cause this again with your chain as short as it is.
Not sure about the problem but pretty sure the chain is too short.
There was actually a Tyler Pearce/ Vegan Cyclist video where something like this happened during a race and he couldn’t for the life of him figure out why. It was something like that pin separated or broke and through chain slap ended up on the other side.
Chain is too short.
OP show a picture of RD and cage with it corrected in the biggest gears.
I have seen an incorrectly routed chain before. I have even incorrectly routed change myself.
The only thing that change should be touching after it leaves the rear cogs are the two jockey pulleys on the derailleur. The only thing.
Misrouted chain it would appear
Wrong!
It’s a common problem. It’s just routed incorrectly
Routed incorrectly? Yes I have
lol somehow