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I noticed that my rear wheel wasn't straight and even after realignment it wouldn't stay straight. After some investigation I noticed that my rear dropout appears to be worn out:

enter image description here

Is this the problem? What is the cause? Is this normal for a bike that is a little less than 2 years old? Is there any repair option aside from changing the frame?

The quick release was bent and replaced some months ago.

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    It looks to me like a bearing has gone bad and is causing the axle to twist in the dropout. This has worn away the dropout. (Or possibly the axle was simply not tightened properly.) – Daniel R Hicks Sep 1 '18 at 13:03
  • @DanielRHicks Thank for the assessment. How do I check bearing? – someonr Sep 1 '18 at 13:10
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    What kind of bike, is it and what type of riding are you doing? – Argenti Apparatus Sep 1 '18 at 17:38
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    Side point - the damage to the dropout is a SYMPTOM whereas the CAUSE remains unknown. So fixing the dropout will resolve the crooked wheel, but it may happen again, and faster, if you don't resolve the cause. – Criggie Sep 1 '18 at 23:09
  • Its all speculation here - To me it looks like the QR has probably been clamped on the steel 'collar' (which I presume is the mount for the derailleur hanger). The collar is proud of the frame, so the QR did not grip the frame. The QR is aluminum, so the teeth would not bite the steel collar, meaning it would move around, slide off and come loose. – mattnz Sep 2 '18 at 1:26
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This almost exclusively happens because of external cam quick release skewers not clamping the wheel tight enough.

external QR

Bike manufacturers love them because they're light, cheap, work fine most of the time, and nobody ever questions them when buying a bike. But they never have as much clamping force as internal cam types, and the problem is exacerbated once they're weathered and worn. There are some out there these days coming on some bikes that barely work or don't work. I know it sounds conspiratorial, but it's sadly true. There's a certain bike model I've been dealing with where the skewers just go in the trash, because the resting spot of the cam produces so little clamping force that using the front brake at any speed readily shifts the axle around.

Another possible issue in the same vein is wingnutting down the skewer instead of properly clamping it.

You could try some metal filler on the frame plus a good skewer, like any Shimano. Glob the filler on more than needed and then use files once it hardens to take off the excess and recreate the axle groove. The upshot here is that nice skewers put on so much clamping force that the frame isn't going to receive the kind of stress that caused this. This is a little bit of an experimental solution so I wouldn't expect a shop to do it.

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That's not normal for a two year old bike, even if you are doing a lot of miles on it.

Dropouts do not normally wear because the axle does not move or rotate in them, so there is something else going on that has caused this. As @Daniel R Hicks said in a comment the bearing might be causing the axle to rotate or the wheel was allowed to move around in the frame.

To check the wheel bearings, simply rotate the axle in the wheel by hand, if there is any resistance, roughness or 'notchiness' there is a bad bearing.

  • Replaced QR because it was bent! That rings the usual bell with me. I'd suspect a QR that has been used as a normal screw. It's quite hard to bend a QR when it is tightened as it should be. – Carel Sep 1 '18 at 18:33
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enter image description here

Got a similar issue but it’s a carbon frame... I picked up used on trade. I’m going to give some filler a run as I can’t justify scrapping a frame for some wear.

  • Welcome to Stackexchange - please browse our tour and learn how this is a Q&A format. Your answer is a "me too" and will be much improved once you've tried your fix. Please take photos as you go, and return later to complete this answer. – Criggie Mar 13 at 3:07
  • What exactly do you mean by filler ? The proper stuff would be more carbon fibre. Maybe fibreglass if you can bond them properly. But "filler" could also be pink builders bog, or bondo. So what are you meaning by filler ? – Criggie Mar 13 at 18:49

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