Zee rear mech mangled in wheel

Oli-custumXC · February 2016

Hello! It's my first time posting in here.
Basically, I was cycling home last night and hopped up onto the kerb when I heard a sickening crunch.
At first, I thought it was my rim on the kerb, and when I had the courage to turn around and have a look, my Shimano Zee rear mech found its way in between my spokes and it was completely written off!
fortunately, the wheel is fine (even the spokes).

I wanted to know it this has happened to anyone else? I spent ages researching and shopping for this thing, not to mention getting the right chain tension and fine tuning once I bought it. It was a huge step up from my last mech, but it was supposed to be a mech designed for punishment ...not a component that would falter once gravity turned up...
Should I get in touch with the retailer, or Shimano themselves? ....or is it a lost cause?

It was a shimano Zee shadow plus M640

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oodboo · February 2016

Did you hit the curb straight on or was it at an angle?
I'm just guessing here but to me it looks like the wheel has warped when you hit the curb and pushed the spokes into the deraileur before springing back into shape. I don't think you can blame the deraileur for this. Just an unlucky combination of factors.

cooldad · February 2016

Yep, mech didn't fail, either wheel as above, or not adjusted properly.

Where's the rookie ring when you need it?

The Rookie · February 2016

It looks to me like the jockey wheel got snagged on the largest sprocket, would happen if the chain is on the short side and then the mech gets pulled forward a bit more by the chain wait when landing after hopping the kerb.

The rookie ring wouldn't stop the mech snagging the spokes, only the chain.

cooldad · February 2016

I just wanted to say rookie ring.

Oli-custumXC · February 2016

Thanks for the feedback. I never thought of the wheel warp. I did hit the kerb with a bit of force that would have brought the wheel out to the right on landing, and the carrying momentum would have pushed the mech to the left.
I thought it would be common on a rear deraliur designed for DH to have countermeasures, but that sounds very un-technical of me... would this be more or less likeley to happen on a short cage like the Zee's?

Chunkers1980 · February 2016

Stops not set right and you over shifted, possibly with some flex in the rear end to 'help' it

JodyP · February 2016

I feel your pain. Managed to send my mech through the rear wheel last night, due to a plate on the chain popping off the pin and snagging in the cage. Twisted it into all sorts of shapes.

Monty Dog · February 2016

Have you ever checked rear mech alignment or dropped the bike? Likewise, how is spoke tension? A bent mech hanger / and/or poorly adjusted gears is the usual cause for wrapping the mech around the cassette but the fact that the lower jockey wheel is fouled in the spokes would suggest sideways flexion of the rim might be a factor. TBH hard to blame the mech if it was down to a poor install.

mattyfez · February 2016

Check the hanger.. If the mech has been set up properly it can't physically move too far unless it's been hit by something and bent.

I feel your pain though, similar thing happened to me a while back, sometimes it's just bad luck.

rockmonkeysc · February 2016

Either your wheel has buckled and caught the mech or you have set it up wrong. The Zee is a good mech but like all rear mechs it's designed to bend rather than pass too much force on the the frame in an accident.
Downhill mechs like zee are designed for better performance in extreme riding conditions, they aren't any stronger than any other mech. They have a heavier spring and tougher clutch than normal.

Oli-custumXC · February 2016

I installed it myself, so naturally, I would hate to think I installed it wrong. I've done it loads of times before and i spent ages fine tuning it. Although, i have never checked the spoke tension. I have already ordered another because I love the mech. I will probably get a professional to check the wheel as that's a bit beyond me, but it's a new whee, It might have loosened up with the first bit of use?...

Clockworkmark31 · February 2016

I would have expected the spokes to be bent or snapped with the force.

The fact that the cage snapped says it moved against something with no play. So like rookie said it got caught in the largest sprocket, seems the most plausible idea.

Sounds like it wasn't tensioned properly to me. The limit screws would have stopped this. Just my thought.

Jonesinamilion · February 2016

Had It happen to me many many years ago on an old Raleigh Marauder

I was doing around 30mph on an old ash path, it instantly locked the rear wheel and threw me clean off. Not pleasant at all, cost me many weeks of pocket money to put right too

rockmonkeysc · February 2016

Clockworkmark31 wrote:

I would have expected the spokes to be bent or snapped with the force.

The fact that the cage snapped says it moved against something with no play. So like rookie said it got caught in the largest sprocket, seems the most plausible idea.

Sounds like it wasn't tensioned properly to me. The limit screws would have stopped this. Just my thought.

You'd be surprised how strong spokes are, they could easily break a mech and look fine.

Zee rear mech mangled in wheel

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