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I serviced my old mountain bike after 6 years of use. This included replacing balls and regreasing the hubs of the bike. When I tightened the lock nut on the front axle and checked for wobbling the axle felt like it was okay (no wobble). And when checked if the wheel turned freely, the wheel turned smoothly for almost a full turn but I'm getting enormous friction at one specific angle.

I've loosened the nuts to check if the hub was overtightened. Then friction disappears but wobbling comes in instead.

My front hub is a Shimano HB-RM60. I've replaced my bearings with 3/16" ones.

I've disassembled and reassembled all parts twice, but couldn't find what causes the friction at that particular angle. Now I am not sure whether I cross threaded something or something is in bad condition (like a cup or cone). Is there any advice I could take to check it?

Update:

Apparently my axle is bent. I think this is my problem.Here is picture of axle

Update 2:

I've replaced my axle with the new one, lubed and packed up everything. Now the wheel turns smooth constantly.

  • An addition to answer is, after checking cup and cones, check the axle too.
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  • It's difficult to tell for sure from the photo, but it definitely might be bent. Note that this can then cause spalling of bearing surfaces. And I once had a front hub that was exhibiting similar problems, and it turned out that the hub itself was bent slightly.
    – Daniel R Hicks
    Feb 20, 2018 at 18:58
  • That was the second problem that came to my mind today, i have to check the hub itself
    – Efe Can
    Feb 21, 2018 at 5:30
  • The symptom I had of a bent hub was that I kept replacing the axle and cones and they kept going bad again. Went through three sets before I figured out it was the hub.
    – Daniel R Hicks
    Feb 21, 2018 at 13:01

4 Answers 4

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Disassemble the hub, clean away the grease, and carefully inspect the surfaces of the cups and cones. If you see irregularities then that's probably "spalling" and it means that the part must be replaced.

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Did you mix old ball bearings with new ones? Or mix balls from the left side to the rear? Uneven wear in the ball bearings can cause this.

This is why best practice is to just replace all of the bearings from new ones that come from the same batch/box. They’re so cheap it’s not good to recycle them anyway.

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  • I've not mixed them but when i placed the new bearings in cup it looks like it has more space between each ball eventhough i've used exact same balls according to specs of hub. Unfortunately i dont have my old balls to measure..
    – Efe Can
    Feb 20, 2018 at 10:40
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In general, a recently regreased hub tends to show more friction than it had before the regreasing. In normal circumstances, I would recommend giving it a spin during a ten-twenty kilometers ride and then would recheck if the friction is still bad. However…

It is not clear how "enormous" the friction at that position is. If all the balls are new and the races did not look to be beaten to death or at least looked evenly worn, the only explanation I can imagine is that you've put more balls to one or both sides of the hub than necessary. Did you count amount of old balls per side? It is safer to set one ball less than optimal than to cram in one ball more.

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this wouldn't account for enormous friction, but one way to check for non visible palling on your bearing surfaces is with a ballpoint pen, just draw around the race and you'll be able to feel any cracks or divots. (if you hadn't said you'd replaced the bearings i'd say it was a broken ball)

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