Losing drive at the rear wheel

Dunkindiver
Dunkindiver Posts: 143
edited November 2010 in Workshop
HI, I keep losing drive at the rear wheel, with the pedals spinning round and then suddenly engaging (most disconcerting at junctions when I decide to make a dash for it!)

What part is causing this?, as I had a new cassette fitted a couple of months ago, or is it the hub, and how easy it to change?

Comments

  • fleshtuxedo
    fleshtuxedo Posts: 1,856
    It's your freehub.

    Depends what make of wheels you have, but it shouldn't be too difficult to dissemble the freehub and find out what's causing it. Most work on pawls, small lugs that are held outwards on tiny springs against the inside of a ratcheted wheel. This gives the ability to spin in only one direction and enable freewheeling. It's likely to be either worn out (so the pawls are slipping against the ratchet wheel, or gummed up with grease (so the springs are unable to push the pawls against the ratchet wheel).

    What wheels are they? You should be able to google some info/diagrams to help you. It's not normally difficult if you're a reasonable hiome mechanic.
  • Monkeypump
    Monkeypump Posts: 1,528
    DId you change your chain at the same time as the cassette? If not, that could be your problem (old chain + new cassette doesn't always work well).
  • HI guys thanks for the advice.
    I'll have a good look , The wheels are the originals on my 20 year old Marnin MTB, so they could be anything!

    I did change the chain when the cassette was replaced

    Cheers DD
  • Monty Dog
    Monty Dog Posts: 20,614
    Freehub is probably borked - particularly if it's 20 years old. If it's a Shimano hub you should be able to get a replacement for about £15. A short term fix would be to pour some light oil into the freehub or spray some WD40/GT85 in there - this could get you going but the fact that it's not engaging indicates either worn or sticky pawls. Check out www.parktool.com for info on servicing your hub / freehub replacement
    Make mine an Italian, with Campagnolo on the side..
  • billysan
    billysan Posts: 575
    Monkeypump wrote:
    DId you change your chain at the same time as the cassette? If not, that could be your problem (old chain + new cassette doesn't always work well).

    Generally the other way round.

    Old cassette + new chain = Wont work (chain will just ride over the top)
    New cassette + old chain = works ok (but will wear your new chain very quickly)