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Gears Slipping

flappy8flappy8 Posts: 171
edited October 2010 in The workshop
I have a Spesh Sirrus with Shimano 105 3x10 gears. On the last few trips when in lower ratios the chain appears to slip on the rear cogs. I say 'appears' as when I get off to turn the cranks by hand and have a look its fine. Its when under some pressure.
The hanger looks straight and I'm fairly sure there is no significant chain stretch.

I cant replicate it on a stand only in traffic when looking around is more important!

Any ideas welcome!
MTB or Road - They are both good!


  • rhannrhann Posts: 383
    worn out cassette/chain? take it to lbs for chain, does the cassette look like shark teeth?
  • flappy8flappy8 Posts: 171
    The bike has only done 1500 miles fron new and the cassette looks fine.

    Anyone got a view on how many miles you should gt out of a 10 speed chain?
    MTB or Road - They are both good!
  • When you say slip do you mean between 2 cogs? (i.e. when on the 4th cog it goes onto the 3rd cog and back onto the 4th)?

    If so it probably just needs re-indexing using the little adjuster that is at the point where the cable goes into the rear deraileur.

    Im a bit of a newbie with bikes and found this was a lot easier than it sounded...

    Basically made sure there was no clicking when on the smallest cog at the back.
    Put it onto the second smallest cog at the back.
    Turned the adjuster a quarter turn to the left and try it each time... keep doing this until the chain starts clicking and trying to jump onto the 3rd smallest cog at the back.
    Now just turn the adjuster enough to the right to stop the clicking.

    I was having a nightmare with my chain trying jumping between the third and fourth cog at the back, did this with the second smallest cog and all the other gears magically work fine.

    My bike is a Kona Jake the Snake that has done around 1500 miles as well.
  • flappy8flappy8 Posts: 171
    No I mean it appears to slip over the gears, although I guess it must be between the two. The indexing appears to be accurate when on a stand though.....
    MTB or Road - They are both good!
  • fnegronifnegroni Posts: 794
    My 2p worth:

    Might be the freehub pawls not engaging fully and slipping.

    Happens when dirt gets in there or lube is washed out. Some freehub systems have low contact seals (mine does) and will allow water in occasionally.

    In this case, it is paramount the freehub body can be taken off the axle easily. Fortunately mine is.

    Just put some teflon-base lube in there and things might improve.

    See: ... highlight=
  • nyanzanyanza Posts: 68
    Slipping under load as you describe really does point to the cassette being worn. Personally I've munched through the 11 and 13teeth on a cassette in far fewer than 1500 miles.
    As has the guy on this thread with the same issues as you:
    You might not be able to see the worn teeth, but use a finger nail and feel for a small clumping of the metal on the leading edges of each tooth.[/url]
  • flappy8flappy8 Posts: 171
    And the winner is:
    ....'Might be the freehub pawls not engaging fully and slipping' - you have the correct answer! After getting a bit if cleaning fluid in there they work perfectly. However the act of getting the fluid in there may just give me more issues in the longer term!.

    Thanks all for your help, John
    MTB or Road - They are both good!
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