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Gears slipping in fourth cog at rear

phillipjohnsonphillipjohnson Posts: 117
edited August 2010 in The workshop

I got a bike about 4 months ago and the gears have been working really well (Shimano 105)

I use the bike quite a lot and have done about 700 miles on it.

When I was out at the weekend I had a rear puncture and had to change my back inner tube (wheel off and while propped up upside down the bike fell onto its side).

After the ride I brushed the deraileurs down while cleaning the bike and lubed them afterwards.

I don't know if it's either of the things above, but since that day when I put the chain onto the fourth cog at the back, if I am going uphill or putting a lot of pressure on the pedals the chain keeps clunking between the 3rd and 4th cog. It's fine on all the other cogs.

Any ideas what could fix this? I am quite new to cycling and don't know too much about adjusting gears etc.




  • pitchshifterpitchshifter Posts: 1,476
    Are all the teeth straight? One may be bent causing the "Clunking"?
  • Rear wheel not fully in the drop-outs? Slacken QR abd re-tighten with bike on the ground, see if wheel re-seats.
    Or if bike fell over, maybe bent the mech hanger? Lean bike against wall (so it's straight) and see if mech's jockey-cage leans in or out. Straighten by gently bending with man-hand.
    FCN16 - 1970 BSA Wayfarer

    FCN4 - Fixie Inc
  • Thanks for the suggestions.

    I think it's the wheel not fully seated.

    I undid the quick release and jiggled it a bit then tightened the quick release.

    Just did a 56.4 mile ride and no slipping :-)
  • I had what sounded like exactly the same problem as you,it seemed to come and go for no apparent reason.I then mentioned it to my LBS,the bloke there walked outside to my bike and made a minor turn on the cable adjuster on the rear deuraillier..Job done, no problems since.Hope this helps,if the fault re-occurs.
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