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I am getting a grinding noise from the rear wheel which has got louder and is causing increasing resistance over the last few weeks (I live in the Netherlands so cycle every day).

The cassette has been taken apart and cleaned in case it was dirt between cogs, this didn't help. From this I am guessing it is bearings? I've been told that if I took it to a bike shop they would just replace the rear wheel which would be very expensive. Was hoping that maybe the bearings could be changed or that its a different problem?

My bike is a Scott Mountain bike with 21 gears.

Thanks so much, any advice would be really welcome as I am a student with little money :(. Thanks, James

  • Grinding noise from the rear can be pretty much anything. Have you tried spinning the wheel out of the bike? – Batman Feb 13 '16 at 15:17
  • Some (many) hub bearings can be repaired depending on how serious the damage is so a bike shop may not charge a fortune. Having the whole hub replaced and therefore the wheel rebuilt would probably be a similar cost to a new wheel. But I replaced a wheel recently and although I spent about 100 EUR I was after something very slightly out of the ordinary, which more than doubled the cost. – Chris H Feb 13 '16 at 16:05
  • Assuming this is a standard derailleur-style bike, the grinding noise, if not due to some external rubbing against the frame (which should be visible) would be due to the bearings going bad. If the bearings are of the loose ball/cone/cup variety then this can be cheaply repaired, if not too far gone. If the bearing are cartridges it's a bit more complicated, but still doable. However, if this has been going on for "the last few weeks" then there's a good chance that the hub is irreparably damaged. – Daniel R Hicks Feb 13 '16 at 18:47
  • @DanielRHicks If they're cartridge bearings, the hub itself might well be fine, even after several weeks of grinding, and it's just a question of giving it to a bike shop to source and fit some replacements. It takes considerable abuse to damage the bearing races. – Will Vousden Feb 19 '16 at 12:29
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    @WillVousden - The bearings don't have to seize completely, they just have to grab intermittently. Easily possible if the bearings are "crunching". – Daniel R Hicks Feb 19 '16 at 13:16
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There are two main types of cycle wheel, cup and cone and cartridge bearing. Cup and cone bearings are fairly easy to service yourself with some simple tools, normal and cup and cone spanners and some grease. Cartridge bearing hubs need more specialist tools, presses to install and drifts to knock the old bearings out.

You can tell which sort you have by looking at the axle, if it's got a nut and a thin lock nut then it's probably cup and cone, google some pictures to see what they look like.

If it is cup and cone then taking it apart (only undo 1 side btw or you'll lose the centre of the axle), cleaning the loose ball bearings you'll find under the cones, then regrease and reassemble may sort the problem; however if its actually as bad as you sugest the ball bearings may need replaced and if the races that the ball bearings sit on are pitted then the wheel may be beyond help. There are lots of videos on the web showing this process.

If it's a cartridge bearing hub then your local shop might be the way to go unless you want to invest in some tools.

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    Given how cheap bearings are, I see no reason to reuse them. Servicing a hub is a reasonably challenging task and somewhat messy, so leaving it to a shop is not a bad option. – Batman Feb 13 '16 at 18:25
  • @Batman - I agree that any time a hub is taken apart to the extent that the balls are removed and everything cleaned up, one might as well replace the balls. It's false economy not to. And the cones should be carefully checked for wear and replaced if any significant wear is seen. – Daniel R Hicks Feb 13 '16 at 18:49
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I'd suspect bearings too, but other things to check as well....

  1. wiggle the rear wheel rim from side to side. There should be no (very minimal) detectable sideways wobble.

  2. disconnect the chain from the rear wheel or from the front chainring. Then the front crank should spin smoothly with no detectable sideways wobble.

  3. hang the bike and spin the rear wheel. Look at the brakes and the seat/chain stays to see if the wheel is getting close at any point in its spin. This would show if its out of true.

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