DI2 vs Rear Derailleur Hangers

Discuss light weight issues concerning road bikes & parts.
dgran
Posts: 62
Joined: Mon Dec 03, 2012 10:04 pm

by dgran

This is a little concerning as I recently built up a bike with Di2. My frame is Titanium and my shop says that this is ideal for Di2 because the hanger is the strongest possible, being built from one welded material. Are these problems primarily a result of frames with detachable hangers? Am I in a safer position with a Ti bike?

by Weenie


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

by dano

Hey guys,

Dan here again.......steel hangers are an option, but let me pose this.....if the hanger doesn't give, something else will. That could be the destruction of a Di2 rear derailleur or even worse, the expensive carbon frame everything is attached to. 7075 AL is also an option, but as they tend to be more brittle than 6061 AL, bending them back in the event of bike tipping over or slight topple when riding will be tough, they will simply break off. We've discussed stainless steel as well, and while stronger than 6061, the difficulty machining them on a mass scale would create a very expensive part.

Let me ask this? How much would you, as a consumer, be willing to spend for peace of mind at the rear derailleur attachment point? You drive the market, drive the demand and we'll work on producing!

As always, we appreciate the feedback!

Dan

Geoff
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Location: Canada

by Geoff

I'd buy steel...

Svetty
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Location: Yorkshire - God's Own Country

by Svetty

I always thought the the hanger was designed to be the weak link in the chain so that in the event of a crash or loading it was the hanger (cheap) that broke and not the mech or frame (expensive)......

mattr
Posts: 3415
Joined: Fri May 25, 2007 6:43 pm
Location: The Grim North.

by mattr

It is meant to be the weak link, but some of them are simply too weak. The loads rear mechs can now apply is bigger than it ever was, and Di2 is another step up. The hangers are still essentially as they were 20 years ago.

We had one in a shop (many many moons ago) that snapped before the bike had even been ridden. It'd been on the shop floor for ages and everyone playing with the gears had eventually fatigued the hanger.

5 8 5
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Joined: Sat Jul 29, 2006 2:36 am
Location: UK

by 5 8 5

Some of the Pro teams replace them with steel. They've got lots of replacement bikes and frames though!

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

by Geoff

Yeah, and they guard them jealously! I keep asking for a steel hanger, but they don't have enough to go around, so they take them off before giving me my bike and keep using the steel hangers year after year. :(

DaleRider
Posts: 53
Joined: Thu Apr 18, 2013 12:34 pm

by DaleRider

The hanger does need to be the weak link in the event of a crash, but it should be strong enough to not break simply from the force applied to it by the derailleur or vibrations from the road.

5 8 5
Posts: 1353
Joined: Sat Jul 29, 2006 2:36 am
Location: UK

by 5 8 5

Geoff wrote:Yeah, and they guard them jealously! I keep asking for a steel hanger, but they don't have enough to go around, so they take them off before giving me my bike and keep using the steel hangers year after year. :(

With your connections Geoff, I'm surprised!

They'll also remove them from the broken carbon frames and put them onto the new ones!

Geoff
Posts: 5022
Joined: Sat Dec 13, 2003 2:25 am
Location: Canada

by Geoff

Some Team mechanics make them by hand from plate stock! I can see why they keep them...

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Tinea Pedis
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by Tinea Pedis

5 8 5 wrote:With your connections Geoff, I'm surprised!

Why do you think Geoff doesn't mind if the hanger kills the chain stay ;)

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

by thisisatest

Many, many frames use hangers that are extremely poorly engineered. some sandwich the dropout, but thread into a very thin part, only having one or two threads of engagement. They will also shift left/right by having one side of the "sandwich" slide up and the other side will slide down. This case I believe is due to bad modeling on a computer- if the sides were truly anchored down, it would be a very stiff hanger.
some other hangers have a very slim shape when viewed from the side, then get thicker off the back of the frame to possibly better support the derailleur. but right at the transition, there is a hole for a screw and barely any hanger material left around it. any force creases the hanger right at the hole.
And a LOT of hangers are mounted on dropouts that AREN'T FLAT AND SQUARE. Then you tighten your QR and the whole derailleur tilts to the left, requiring an alignment of a brand new hanger. Too bad it's the type described above and bends at an unintended failure point.
WheelsMfg made some limited edition titanium hangers for Cervelos a little while ago. unfortunately, they never made them for their most current hanger shape.

Sent from my EVO using Tapatalk 4 Beta

jooo
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Joined: Wed Feb 02, 2011 3:48 am

by jooo

Image
If only!

g32ecs
Posts: 143
Joined: Thu Apr 11, 2013 2:50 am

by g32ecs

I always wonder on how companies that integrate the hangers handle warranty claims (do they refurbish the frames?). I'm talking about Carbon frames.

I think it's a terrible idea to integrate these things onto the frame. They basically have to replace the whole frame just for the hanger.

by Weenie


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eliflap-scalpel
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by eliflap-scalpel

i had a Scott Addict HTC Highroad bike, no issue.

i had a Cannondale SuperSix HM, no issue.

i have a LTK since few days, no issue

i have the Di2 on a 29er too:

i have a Flash 29er, no issue, but here i did a custom hanger, longer and with some mm of backwards, so very stiff, although is made of 7075 alu
http://eliflap.it/

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