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So I opened my rearhub, because there was a lot of dirt in there after 4000 kilometers usage and I found that there is a little dent in the bearing cone. When I slide a bearing ball over that "dent" I can not feel it, also it is smaller than the image makes it look.

Should I try to get a replacement cone?

Dent in bearing cone

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    Replacement cones are cheap. It's not an emergency, but you should get the part ordered. And check the corresponding cup -- that's the more critical (and expensive) piece. – Daniel R Hicks Mar 24 '17 at 17:08
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    (The spot is probably due to a piece of carp that got in there somehow. May even have been from the last time you repacked the bearings.) – Daniel R Hicks Mar 24 '17 at 17:10
  • This is called Spalling if you want the technical term. – Criggie Mar 24 '17 at 17:52
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    @Criggie - Actually, it's hard to say whether it's spalling or not. Spalling is where the metal flakes off, and the marks in the picture appear like they may be due to a fragment of crud that somehow got in there and was rolled on by the balls, to make a dent. – Daniel R Hicks Mar 24 '17 at 23:55
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    @Criggie - Except it's not spalling if the metal was dented, vs breaking loose. And the mark does not look like your typical spalling, more like a dent. – Daniel R Hicks Mar 25 '17 at 11:32
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Anywhere there is a cone, there is also a "race" that the bearings sit in. The cone holds the bearings in place against the race. The picture you have posted shows the very definition of "pitted cone". As the wheel turns there will be increased friction when the bearings contact the pit. It will get larger and eventually the bearing will freeze in the pit. Even if it's just for a moment it will cause increased friction on the race.

Cones are very inexpensive relative to the cost of a new hub and the wheel building labor it takes to replace it, or relative to the cost of a new wheel. I would absolutely replace it.

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    Ok I just went to next Bike store and the guy there did not have a spare part, but said the same thing you did. Once there is a pit, it will just grow and eventually cause more problems. I should also look at the other side of the bearing, because there will likely also be damage (In my case the inside was OK). Now my next problem is finding the correct spare part online. Thanks! – Martin Mar 24 '17 at 16:19
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    @Martin Try a real Local Bike Shop and not a generic sports shop. Any real LBS has 20 different types of cones – Criggie Mar 24 '17 at 17:51
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    Agreed, go to a good local bike store. You won't find it online or will have a very hard time finding the exact match using just photos. – RoboKaren Mar 24 '17 at 18:41
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    @Martin The easiest way to get a replacement might very well be to simply get an entire replacement hub of the same model. And given the way bike parts are distributed and sold, there's a good chance you can get an entire hub online for less than you'd pay for just the replacement parts. – Andrew Henle Mar 24 '17 at 19:01
  • I found a replacement axle with two cones and various nuts and spacers in a blister pack was cheaper than a single cone by itself because mine was an oddball (expensive) size. – Criggie Mar 25 '17 at 5:46

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