Chain slipping on cassette under load

Discussion in 'Bicycle Mechanics and Repairs' started by Dec66, 6 Dec 2018.

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  1. Dec66

    Dec66 A gentlemanly pootler, these days

    Location:
    West Wickham
    On my BTwin, following a recent cassette & chain replacement, the chain is slipping on the cassette when put under load (so, for example, if I'm in too high a gear pulling away from a junction). It's as if the chain is trying to rip itself off.

    LBS have adjusted grearing, cable tension etc., to no avail. He reckons it's a freehub issue, which would be annoying as the wheels and hubs (Shimano R501) don't have that many miles in them.

    Would a freehub body replacement do the trick, or is it a new wheel for me?
     
  2. Threevok

    Threevok Carpe Rotam

    Location:
    South Wales
    Last time I had this problem after replacing both the chain and cassette, it was a worn chainring causing the problem

    Is it happening on every chainring ? (assuming you have a double or triple chainset)
     
  3. OP
    OP
    Dec66

    Dec66 A gentlemanly pootler, these days

    Location:
    West Wickham
    It's a triple, but I rarely use the inner and middle rings.

    I'll try it on those and see what happens.
     
  4. Rooster1

    Rooster1 I was right about that saddle

    Chainring most likely
     
  5. Yellow Saddle

    Yellow Saddle Veteran

    Location:
    Loch side.
    Cassette, most likely. But lets have a good side-on picture of that chainring. Chainrings do slip if they are very, very, very worn. Cassettes slip if a new chain is fitted to an old cassette or, if you have had a significant change in terrain where you are suddenly using a gear you have not used in many hundreds of miles. In other words, the used gears wear with the chain but when you suddenly use an unused one, the chain doesn't mesh with it.

    It could of course be the freehub, but they don't fail like you've described. They slip before power is applied, now during applied power.
     
    davidphilips and Threevok like this.
  6. OP
    OP
    Dec66

    Dec66 A gentlemanly pootler, these days

    Location:
    West Wickham
    New chain, new cassette.

    Pics later.
     
  7. I like Skol

    I like Skol I'm adamant I haven't got any PPI....

    Location:
    Ashton-under-Lyne
    Is it the right chain for the cassette? No chance a 6/7/8 speed chain has been fitted to a 10 speed bike is there?

    I have witnessed this 1st hand on a ride with @dan_bo when his drivetrain started slipping. After the 2nd or 3rd incident I had a look and spotted the shark fin teeth on the chainring. Once it happens the first time it doesn't take much to do it again.
     
    midlife likes this.
  8. dan_bo

    dan_bo How much does it cost to Oldham?

    Location:
    Failsworth
    A season of cross'll do that.
     
  9. OP
    OP
    Dec66

    Dec66 A gentlemanly pootler, these days

    Location:
    West Wickham
    8 speed cassette, suitable chain.
     
  10. I like Skol

    I like Skol I'm adamant I haven't got any PPI....

    Location:
    Ashton-under-Lyne
    FTFY :okay:
     
  11. davidphilips

    davidphilips Über Member

    Location:
    Onabike
    Could there be a tight link on your new chain? Lots of pictures please and i am sure Yellow saddle will find the solution for you.
     
  12. dan_bo

    dan_bo How much does it cost to Oldham?

    Location:
    Failsworth
    Oh go and polish yer headset
     
    Pat "5mph" likes this.
  13. OP
    OP
    Dec66

    Dec66 A gentlemanly pootler, these days

    Location:
    West Wickham
    IMG_20181208_094819871.jpg
    Outer chainring, looking more "peaky" than "shark finny"

    IMG_20181208_094859731.jpg
    Cassette
     
  14. gbb

    gbb Legendary Member

    Location:
    Peterborough
    Big chainring definitely wants replacing.
     
    Ajax Bay likes this.
  15. I like Skol

    I like Skol I'm adamant I haven't got any PPI....

    Location:
    Ashton-under-Lyne
    I thought you said new cassette? Cassette looks decidedly used to me, look at the burrs at the working edge of each tooth. Chainrings are dead! Big ring and small ring should have been changed long ago. Strangely the middle chainring doesn't look as bad, maybe you should use it more.
     
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