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I got my first bike with the UDH in January, and have broken two derailleurs since. The first time, the hanger didn't even bend at all. A stick got tangled up and it broke right off. The second time the hanger bent slightly, but not enough to stop the derailleur from breaking in half. I've never broken a derailleur in half before, other than once when I fell of a rock skinny directly on to it. Is this a case of extremely bad luck, or does the SRAM UDH not work well in protecting the derailleur?
 

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From what I can tell the SRAM UDH gear hanger isn't intended to be a weak link that breaks to protect the rear derailleur and frame. It's quite a solid piece of metal that seems to be intended to rotate backwards on an impact as its way of protecting the rear derailleur. It doesn't seem to be a breakaway bolt style anymore as was common a few years ago.

With the derailleurs breaking in half are you using a Shimano rear derailleur? I was looking at the pictures in this emtb forums thread of broken rear derailleurs and they appear to be more likely to snap than the gear hanger!

Anyone seen a mech break like this? - EMTB Forums
 

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so they are not plastic? I’m confused now. Maybe they come in different materials.
 

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Replaceable derailleur hangers weren't made to protect the derailleur, they were made to protect the frame. If they weren't replaceable and got bent all to hell your rear triangle would be shot.

It looks to me that Sram's UDH is seamed down the middle. I don't know that for sure, It just looks that way. Regardless, seems like a great design imo.

Sent from my Pixel 4a (5G) using Tapatalk
 

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Replaceable derailleur hangers weren't made to protect the derailleur, they were made to protect the frame. If they weren't replaceable and got bent all to hell your rear triangle would be shot.

It looks to me that Sram's UDH is seamed down the middle. I don't know that for sure, It just looks that way. Regardless, seems like a great design imo.

Sent from my Pixel 4a (5G) using Tapatalk
Last one i used worked perfectly. This one you can see the New derailleur is a little crooked. I would have expected a new derailleur to be straight.
 

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Last one i used worked perfectly. This one you can see the New derailleur is a little crooked. I would have expected a new derailleur to be straight.
I reckon they are "straight", but with such variability to each dropout/frame they will need to be "straight" to that specific application. As such they're designed to be manipulated.

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Here’s a picture showing how a SRAM UDH hanger responds to a stick in the spokes.

The hanger rotates backwards instead of bending (in this picture the SRAM GX derailleur has the cage held open on its pin)




Bicycle Wheel Bicycles--Equipment and supplies Bicycle frame Crankset
 
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