Crunching from a Shimano Single Speed Freewheel.

muddly
muddly Posts: 20
edited April 2010 in The workshop
Hi

Can anyone help. My Shimano Single Speed hub has developed a crunchy, gritty noise. I normally try and inject some chain lube into the two small holes on the front plate of the hub, but this does not seem to be helping, has anybody got any ideas?

Can I re-grease my hub?

Thanks in advance.

Comments

  • vorsprung
    vorsprung Posts: 1,953
    muddly wrote:
    Hi

    Can anyone help. My Shimano Single Speed hub has developed a crunchy, gritty noise. I normally try and inject some chain lube into the two small holes on the front plate of the hub, but this does not seem to be helping, has anybody got any ideas?

    Can I re-grease my hub?

    Thanks in advance.

    I would guess that the noise is probably a broken bearing inside the freewheel

    Assuming that the hub is a XT or similar one with a single speed adapter kit it should be possible to disassemble the hub with a couple of cone spanners

    See the Park Tool website for a description of how to service hubs

    http://www.parktool.com/repair/readhowto.asp?id=118
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  • muddly
    muddly Posts: 20
    It's not an adapted hub. It's just a single speed freewheel on a single speed hub. Does that make any difference?
  • muddly
    muddly Posts: 20
    It's not an adapted hub. It's just a single speed freewheel on a single speed hub. Does that make any difference?
  • wgwarburton
    wgwarburton Posts: 1,863
    muddly wrote:
    It's not an adapted hub. It's just a single speed freewheel on a single speed hub. Does that make any difference?
    A bit. Does the hub grind when the free-wheel is turning or the free-wheel grind when the wheel is still? Cheers, W.
  • muddly
    muddly Posts: 20
    Crumbs. Umm I think that the freewheel grinds when I stop pedalling, but the wheel is turning. I will double check en route to work tomorrow and reply. On another allied question, at what point do you change the chain on a single speed? According to my chain tool I'm at .75 which would be about when you would change the chain on a multi gear bike.

    Thanks.
  • wgwarburton
    wgwarburton Posts: 1,863
    muddly wrote:
    Crumbs. Umm I think that the freewheel grinds when I stop pedalling, but the wheel is turning. I will double check en route to work tomorrow and reply.

    If that's the case then it's probably the freewheel that's gubbed. Try replacing it and see if the problem goes away. To double-check you could take the chain off the freewheel and spin the back wheel. If the hub runs smoothly, it's likely not the problem. Now spin the freewheel with the wheel stationary & the chain off to see if it grinds.
    You could try to repair it but it won't be cost-effective, even if it's possible.
    On another allied question, at what point do you change the chain on a single speed? According to my chain tool I'm at .75 which would be about when you would change the chain on a multi gear bike. ...
    Pretty much the same- your chainring & sprocket will last longer if you replace the chain as it wears. After a while the new chain won't run on the old sprocket and you'll need to change that, too. Ultimately, of course, the chainring goes.
    How long they last depends on cleaning, oiling, road conditions etc and also on your components- I'm wearing out cheap alloy 3/32" chainrings quite quickly on the winter hack, whereas the 1/8" sprockets seem to last quite well (~30% more metal on the wear faces).

    Cheers,
    W.

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