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Rear derailleur snapped off

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Rear derailleur snapped off

Old 09-15-11, 03:12 PM
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Planet Fox
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Rear derailleur snapped off

My SRAM Red rear derailleur has just snapped off whilst going up a hill. In the process it has broken a small section of the carbon frame. Has this happened to anyone else? I've kept good care of the bike and it has had no knocks. Where do I stand with the manufacturer? It is less than 6 months old.
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Old 09-15-11, 03:20 PM
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Pics? Sounds like a derailer hanger or frame defect
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Old 09-15-11, 03:22 PM
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had the same thing happen... trashed the derailleur, hanger and scuffed the carbon, but no real physical damage. I built the bike so I was on my own. If it's only six months old, I would definitely take it to the place of purchase and see what they can do for you... if nothing contact the manufacturer.

Out of curiosity, who's the manufacturer?

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Old 09-15-11, 03:28 PM
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It's a Planet X bike. I will be taking it back to the bike shop in the morning.
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Old 09-15-11, 03:36 PM
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Originally Posted by Planet Fox View Post
It's a Planet X bike. I will be taking it back to the bike shop in the morning.
I hope it wasn't a PX Stealth Pro! I just bought one...with SRAM Red
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Old 09-15-11, 03:45 PM
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If the limit screw wasn't set correctly or the derailleur hanger was bent, it could have been caught in the spokes. That will tear the derailleur right off.
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Old 09-15-11, 03:51 PM
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Planet Fox
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It wasn't a stealth pro it was a nano light.
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Old 09-15-11, 04:17 PM
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My alu CX bike had something like this happen three weeks ago. I was riding when the RD arm snapped. It caught between the chain stay and spokes, locking the rear wheel. Very exciting. I had to replace the RD, hanger, and all the drive side spokes.
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Old 09-15-11, 04:28 PM
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Originally Posted by gadabout007 View Post
had the same thing happen... trashed the derailleur, hanger and scuffed the carbon, but no real physical damage. I built the bike so I was on my own. If it's only six months old, I would definitely take it to the place of purchase and see what they can do for you... if nothing contact the manufacturer.

Out of curiosity, who's the manufacturer?

That isn't the derailleur, it is the hangar that snapped.

Can't figure out by the TS post if it was the actual derailleur (extremely rare to snap the derailleur), or the hangar..which is designed to snap off to protect the frame and other parts. But not under a simple climbing load.

Sounds like a defective hangar.
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Old 09-15-11, 07:00 PM
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What condition is the chain in?

You were climbing, right? The chain would be under significant load - if one of the side plates came loose, it can grab the derailleur as it tries to go through.

6-month-old bike? When was the last time you cleaned/lubed the chain? Or checked it for wear?
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Old 09-15-11, 08:58 PM
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you'll need a new der. hanger. the derailleur may be ok.
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Old 09-15-11, 09:14 PM
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Happened to my buddy's trek, but his bike isn't 6 months old. More like 6 years old. Not super old, but it raised warranty issue questions for a little bit. They are replacing the frame luckily. The hangar is screwed though!
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Old 09-15-11, 09:15 PM
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Originally Posted by zigmeister View Post
That isn't the derailleur, it is the hangar that snapped.

Can't figure out by the TS post if it was the actual derailleur (extremely rare to snap the derailleur), or the hangar..which is designed to snap off to protect the frame and other parts. But not under a simple climbing load.

Sounds like a defective hangar.
A defective hangar!?!?!

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Old 09-15-11, 11:48 PM
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They don't generally snap all by themselves. They're on the slack side of the chain, so under very little pressure no matter how hard you are riding. What can cause them to break is the chain getting caught in the RD or the RD going into the wheel. Road debris caught in the chain, or a broken side plate are the usual causes of a stuck chain. If the chain can't move through the RD, the force from you pedaling will rip it right off.
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Old 09-16-11, 08:29 AM
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Originally Posted by ErichM View Post
A defective hangar!?!?!



Glad you have time to correct my typos....
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Old 09-16-11, 08:47 AM
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Originally Posted by ********** View Post
Pics? Sounds like a derailer hanger or frame defect
sounds like a limit screw not adjusted properly.
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Old 09-16-11, 09:09 AM
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Originally Posted by merlinextraligh View Post
sounds like a limit screw not adjusted properly.
Bingo. Too short of a chain would put a lot of stress on the hanger as well especially if the OP was climbing big/big.
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Old 09-16-11, 01:36 PM
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6-month-old bike? I'm betting lack of chain maintenance is the single most-likely cause.

Offhand, 50% chance failed chain, 25% chance limit screw, 25% chance road debris, 10% chance "other".

Yeah, it don't add up to 100%. Sue me.
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Old 09-16-11, 02:28 PM
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Originally Posted by zigmeister View Post
Glad you have time to correct my typos....
Yes, using Google image search to find hangar took a long time. I'm glad you can appreciate my commitment to improving communication on the Internet.

Being you used the word multiple times, I have a hard time believing that it was a typo. I'll take the time to turn to Wikipedia for an explanation of typo.

The term includes errors due to mechanical failure or slips of the hand or finger,[1] but usually excludes errors of ignorance, such as spelling errors.
(emphasis added).

You're welcome!
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