DI2 vs Rear Derailleur Hangers

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DaleRider
Posts: 52
Joined: Thu Apr 18, 2013 12:34 pm

by DaleRider

So I'm starting to notice a real problem with DI2. Since there is no spring to allow the derailleur to move in and out on the cassette when the bike tips over or even just having something bump into the rear derailleur has now caused me to replace six hangers on two different bikes this year alone. Four of them on a Tarmac SL3 and two on a SuperSIx Evo.

This last one caused the hanger to snap while riding which sucked everything up into the rear wheel and completely destroyed the carbon cage on my 7970 rear derailleur as well as a few spokes. I really love DI2 but this is starting to get crazy as this latest incident could have resulted in an injury or worse.

Anyone else running into this problem?

Before someone asks, I've been wrenching and racing for almost 20 years now, and everything is set up as close to perfection as it can get.

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shoopdawoop
Posts: 434
Joined: Thu Dec 22, 2011 12:37 am

by shoopdawoop

Yes, I thought I was the only one. I have a cervelo s5 with ultegra di2 and it absolutely shreds derailleur hangers. I've replaced 3 in the last 6 months and it never stays tuned up perfectly like di2 should.

mattr
Posts: 4671
Joined: Fri May 25, 2007 6:43 pm
Location: The Grim North.

by mattr

Uprated hanger? Rather than the cheese spec ones that come from the factory.

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shoopdawoop
Posts: 434
Joined: Thu Dec 22, 2011 12:37 am

by shoopdawoop

I got wheelsmfg and they still get ripped up. Have been considering machining my own but don't know what material to use.

DaleRider
Posts: 52
Joined: Thu Apr 18, 2013 12:34 pm

by DaleRider

The last one that went was a Weels Mfg hanger. At this point I'm really thinking about going back to mech derailleurs.

DaleRider
Posts: 52
Joined: Thu Apr 18, 2013 12:34 pm

by DaleRider

It just got more fun. Turns out that the inner cage plate is compatible with the 7900 but the outer plate is different and no longer in stock. The inner plate is a whopping $209. Looks like I need to hit Fleabay to find a new 7970 rear derailleur and then consider selling off the bike and building something with SRAM Red or DA9000.

DaleRider
Posts: 52
Joined: Thu Apr 18, 2013 12:34 pm

by DaleRider

Update:

Just called Shimano tech support and spoke with Justin (great guy BTW). He said that the 7900 and 7970-RD use the same cage, but the assembly process is slightly different. He also said that the 7970 cages can still be ordered, they just don't have any instock in the US, but the total for both plates is $366. So I have 2 options:

1. Spend $366 on new cages
2. Take one of the 7900 rear dreailleurs I have in the basement at strip the cage from it.

I think I'll be going with option 2 and ordering a few 7900-RDs from Fleabay should this happen again.

dano
in the industry
Posts: 31
Joined: Thu Dec 01, 2005 6:10 am
Location: Colorado

by dano

Hi Guys, Dan from Wheels Manufacturing here, I saw the thread and am interested in the apparent failures of our machined derailleur hangers when used with Shimano Di2 rear derailleurs.

To start out, all of our hangers are CNC machined in our shop from aircraft grade 6061 AL, we do not outsource these as we prefer to keep the machining and QC under our roof. I have been running Di2 (7900) for about 4 years now and have not had any failures due to the strength of the motor in the rear derailleur. A co-worker has also been running the Ultegra Di2 for about a year now on a Cannondale Super 6 with one of our hangers and has never suffered a failure.

Can you be more specific as to where the hangers are failing at? What's interesting, without seeing the hangers firsthand, is that by the frames listed above, all the hangers are attached via small M3 screws, not by the more common chainring bolt or stronger M4 screw. If you still have the failed hangers and are willing to send them back for inspection, I'm happy to replace them for you. Simply message me with the details and I will make it happen.

Thanks,

Dan D.
Wheels Manufacturing

DaleRider
Posts: 52
Joined: Thu Apr 18, 2013 12:34 pm

by DaleRider

Dan,

I don't believe this failure was a result of a defective product. In fact, I'll be ordering a replacement in just a few moments.

On my Tarmac SL3s with DI2 it was the factory hanger that kept stripping threads. I switch to a Wheels one 1100 miles ago and haven't had an issue yet. On the SuperSix Evo, the stock hanger broke after 100 miles and from talking to my MTB friends, they replace the same hangers on their Cannondale Flash frames every weekend.

The hanger that broke on Sunday snapped on the outside of the dropout just below the bolts. I truly believe that this was just a combination of the bike falling over and the DI2 derailleur not having any lateral give what so ever that caused this one to break. I'll drop it in the mail if you'd like to inspect it, but there is no need to send a replacement.

Keep up the good work over there. I've referred my MTB friends to your site so they can stop ordering the cheep OEM ones every week.

Steve K
Posts: 32
Joined: Fri Mar 02, 2007 6:34 am
Location: PGH

by Steve K

I think this has a lot more to do with weak hangers than anything else. The s5 hanger may be the softest I've ever come across, save maybe a caad10. I've had s5 framesets out of the box with broken hangers. Framesets, not complete bikes. I'd be more upset with the frame than with di2.

I did have a wheels mfg hanger on my caad10 that sheared while riding home the one day. I replaced it thinking that it would be a bit stiffer than the stock cannondale one. After it broke, I looked closer and saw that it was thinner where it contacted the frame than the stock one. Both were soft and required a lot of attention, but I'll blame the design on it rather than the quality of the hangers.

em3
Posts: 883
Joined: Tue Dec 23, 2008 2:57 pm
Location: NYC

by em3

DaleRider wrote:Dan,

I don't believe this failure was a result of a defective product. In fact, I'll be ordering a replacement in just a few moments.

On my Tarmac SL3s with DI2 it was the factory hanger that kept stripping threads. I switch to a Wheels one 1100 miles ago and haven't had an issue yet. On the SuperSix Evo, the stock hanger broke after 100 miles and from talking to my MTB friends, they replace the same hangers on their Cannondale Flash frames every weekend.

The hanger that broke on Sunday snapped on the outside of the dropout just below the bolts. I truly believe that this was just a combination of the bike falling over and the DI2 derailleur not having any lateral give what so ever that caused this one to break. I'll drop it in the mail if you'd like to inspect it, but there is no need to send a replacement.

Keep up the good work over there. I've referred my MTB friends to your site so they can stop ordering the cheep OEM ones every week.



Hmmmm....so which is it, a defective hanger (i.e. stripped hanger threads) or broken hanger due to rider wear and tear/abuse (i.e. bike falling over on hanger)?? Either way, it doesn't sound like either of these scenarios are consistent with Di2 specific issues, per claims in your original post.

EM3
______________

DaleRider
Posts: 52
Joined: Thu Apr 18, 2013 12:34 pm

by DaleRider

em3,

Actually the broken hangers were all a result in some way of DI2 being on the bike.

Just a brief history of my current stable:

All bikes were assembled by me.

2004 CAAD8 - 12,000+ miles and at least two different mechanical groups every year as I use this frame for all of my testing. The only hanger that broke on this bike resulted from a crash in a crit.

2010 Project Black Tarmac SL3 - 4,300 miles with SRAM Red and no issues with the stock hanger. I installed Ultegra DI2 last fall and had my first hanger strip the threads that bolt it to the drop out after a 50 mile ride. This happened 3 more times with OEM hangers. All of them stripped the same bolt holes after just one ride. I now have a Wheels Mfg hanger on there now and it has held up for 1100 miles. Still running Ultegra 6770.

2011 S-Works Tarmac SL3 - 3100 miles with SRAM Red and not one issue with the OEM hanger. This bike has taken a serious beating as it is my race bike, yet the OEM hanger is holding just fine with a mechanical derailleur.

2013 SuperSix Evo Hi-Mod DI2 specific frame running 7970 group - OEM hanger simply snapped after 150 miles. It was never dropped or bumped into anything, it just broke. I replaced it with one from Wheels Mfg and put another 325 miles on it before it tipped over. Like I said above, I don't believe this one was a result of a defective product. The second break was a result of the tip over combined with the fact that the DI2 derailleur does not move like a mechanical one when a force of any kind is applied to it.

So to answer your question, I truly believe that every hanger I've replaced lately has been a result of having DI2 on the bike.

thisisatest
Shop Owner
Posts: 1980
Joined: Sat Jun 13, 2009 4:02 am
Location: NoVA/DC

by thisisatest

Di2 derailleurs will give when pushed inwards.

Sent from my EVO using Tapatalk 4 Beta

DaleRider
Posts: 52
Joined: Thu Apr 18, 2013 12:34 pm

by DaleRider

Mine don't move when pushed. Although, I'm not pushing all that hard. Didn't think I should have to the get it to move.

by Weenie


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Geoff
Posts: 5395
Joined: Sat Dec 13, 2003 2:25 am
Location: Canada

by Geoff

Try the Scott hangers for soft...

Any replaceable hanger will bend if banged hard enough. I don't think this is just a Di2 problem, either. A steel hanger option would be nice. Dan?

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