Unhappy rear mech

[Miller]

This is a brand new Shimano 11sp transmission with a Metrea rear mech. It runs roughly so I took a close look at it. The lower cage seems to be bent outwards and the chain rides on top of the teeth of the lower jockey wheel. Not crashed, I've only ridden it 30km and I'm sure I'd remember.

[bch]

Looks like bent hanger


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[joejack951]

Clearly (to me) a bent mechanism. Get a replacement, hopefully for free.

Similarly, I once bought a bike online (new) and spent at least two hours trying to get the rear to shift properly, a process which usually takes me 15 minutes max. Several adjustments and a few cassette swaps later, I finally replaced the chain and that cured the issue. It was a Sunrace chain with '9 speed' markings but it measured more in line with an 8 speed chain making it too wide to consistently fit the 9 speed sprockets. Strangest thing I've ever encountered on a brand new bike.

[AJS914]

That a weird one. The lower pulley cannot be meshed correctly with the chain?

[Miller]

Because the pulley cage is bent outwards the chain is unhappy and won't sit into the teeth of the lower jockey wheel. I'm not ruling out a mech hanger issue but the lower cage really does look bent.

[FIJIGabe]

While it certainly looks the way you claim, Miller, I wouldn't say it's 100% certain to be a bent derailleur cage, given several variables: camera angle, hanger condition, reference points. I think the best course of action is to ensure the hanger isn't bent, then have a look at it again. A bent derailleur cage would be a very odd item, even if it is a lower-level groupset.

[c60rider]

I don't think you can clearly be sure what exactly is going on from the pictures alone but the most obvious one is to check gear hanger alignment and go from there. Next thing would be to remove the jockey cages and see how straight they are. Between gear hanger and jockey cage is the most likely cause so rule in or out the main ones first of all.

[Karvalo]

I'm not ruling out a mech hanger issue but the lower cage really does look bent.

The upper jockey wheel appears to be significantly not parallel to the sprockets. Looks like the hanger.

[alcatraz]

Use a hanger calibration tool to straighten it, then try again.

It's best to take a picture in the middle of the cassette. Some normal setups actually angle the cage outwards like this when in the small cogs to the right.

[bikeboy1tr]

The hanger looks straight to me but the cage from the top pulley wheel to the bottom pulley definitely looks twisted from the pics you have there. If the hanger was bent the chain would still run properly on the lower pulley wheel. If the chain was running proper on the last RD then its more likely your new RD. From what I can see of the upper pulley it appears that the wheel is meshing with the chain at that point and from the rear pic it looks as though the top pulley is slightly misaligned with the cassette as thats where the twisting starts with the cage and continues to get worse as it connects to the bottom pulley.