Shimano Di2 rear derailleur disaster
matthewward
Posts: 6
So, had an absolute disaster today. Bought a new bike last weekend. Stevens Xenon Di2 cost £2000 in the sale (reduced from £2700).
First ride today, 37 minutes in and i was going up a short climb. Climbing out of the saddle in 34-something (middle of casette somewhere) then sat down and tried to change down a couple of gears (i.e. easier) to spin up the rest of the climb. As i shifted the rear derailleur clicked a few times and then sheared off the frame, hitting and cracking the right seatstay. I.e. rear mech and frame a write off. Picture attached.
Has anyone had any similar experiences?
First ride today, 37 minutes in and i was going up a short climb. Climbing out of the saddle in 34-something (middle of casette somewhere) then sat down and tried to change down a couple of gears (i.e. easier) to spin up the rest of the climb. As i shifted the rear derailleur clicked a few times and then sheared off the frame, hitting and cracking the right seatstay. I.e. rear mech and frame a write off. Picture attached.
Has anyone had any similar experiences?
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@arthur - have returned it to where it came from (rather not say where at the moment) - fingers crossed! Thanks for the support
It just kind of exploded! i found a small piece of metal on the other side of the road which i think came from where the mech was attached to the bit thats still in place (if that makes sense)
however i had quite a big spill on sunday evening where i landed on the mech after clipping a kerb and then a wall. bike was ridden home gently as i was in no fit state but then not ridden for two days. Then this morning after 3 miles it went.
Look 695 (Geared) - FCN 1
Bowman Palace:R - FCN 1
Cannondale CAAD 9 - FCN 2
Premier (CX) - FCN 6
Premier (fixed/SS) - FCN3
I think your statement that you "...had quite a big spill.....landed on the mech..." pretty much solves the mystery of why that happened.
im not questioning why it failed, not in this instance.
Im just annoyed that the mech hanger snap first or the di2 crash protection didnt kick in.
I am replacing the mech hanger, mech and chain.
Look 695 (Geared) - FCN 1
Bowman Palace:R - FCN 1
Cannondale CAAD 9 - FCN 2
Premier (CX) - FCN 6
Premier (fixed/SS) - FCN3
I'm totally sympathetic to your plight and in a perfect world everything works exactly as it should, but when you hit the deck on the rear mech side, well, all bets are off.
Look 695 (Geared) - FCN 1
Bowman Palace:R - FCN 1
Cannondale CAAD 9 - FCN 2
Premier (CX) - FCN 6
Premier (fixed/SS) - FCN3
might put my new bike on hold for a while after seeing the DI2 fail that badly.
Fingers crossed for the future!
Great result! Are you happy to name the shop now, seems like they deserve some kudos as well as the big S?
Many thanks to the guys in there and especially to the manager Russ.
Sadly i'm now off the bike for 6 weeks with a slipped disc! Can't get a break hey!
I was hit by another cyclist who t-boned my shoulder/right hand side a few weeks back and unbeknown to me at the time he must have also made contact with my rear mech.
I took an initial look at the bike and couldn't see any damage so we both went on our way and about 5 miles later I was riding up a hill and hear a horrid crack and snap and ground to a halt.
There was my rear mech; lodged in my rear wheel completely ripped off like yours. I took the bike to the LBS to replace the di2 mech and spokes and they took a look at the side of the chain stay and there was a unrepairable crack in it.
Focus sent me a replacement frame through their crash replacement service at 50% discount which arrived on Tuesday.
I know things can go wrong with Mechanical derailleurs, but I imagine Di can be more sensitive to Knocks and maybe less warning to potential problems?
These are the kind of things why I stick with mechanical. (and Di is just adding to the troubleshooting list at the back of the instruction manual)
Do Shimano recommend a beefier hanger for Di2?* If they do, then maybe some Di2 specific hangers are actually too beefy?
*I imagine that a Di2 mech moves with more force than a mechanical mech?
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limit screw not adjusted or der hanger bent..shop issue, poorly set up unless you fell down and bent the der hanger.
Do you get limit screws on Di2?
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I returned it (in pieces) and the bent chain to Canyon, who sent it on to Madison (the UK Shimano distributor) for analysis to decide whether it would come under the warranty claim. They rejected the warranty processing as they believe the mech failed as a result of either impact (not true) or incorrect adjustment of the limit screws and B tension screw (both of which I'd presumed Canyon had set up before dispatch so foolishly didn't bother checking).
Despite the mech not being covered under warranty, Canyon kindly sent a new one (maybe guilt?). But because I had removed the plastic guard cassette protector (and forgot to put it back on before taking the warranty claim photos), Canyon didn't cover any the collateral damage that included hub damage from chain, bent spokes, wheel untrue and questionable damage to frame.
IMO I reckon there is a design flaw in the body of the Di2 mechs because ours have all snapped in exactly the same spot and left behind the tension spring and hanger bolt. Forces are obviously a lot greater in the electronic mechs and Shimano have perhaps not yet got the engineering spot on.
I (and a few others) had a Campagnolo Xenon rear mech do exactly the same thing as the OP's so it can happen to mechanical and electronic components. There's no difference to the strain on the rear, the only difference is an electric motor shifts the mech.