Help! Skipping Gears

Nuggs
Nuggs Posts: 1,804
edited November 2008 in Workshop
Hi Gang

My self-built winter bike went for its first shakedown this morning. All good except one problem:

When I'm on the small chainring, the chain skips when I'm using the four smaller sprockets at the rear. Otherwise it's as smooth as you like...

Any ideas?

Merci!

Comments

  • nicklouse
    nicklouse Posts: 50,675
    catching on the pick up teeth on the big ring?

    not that good to use those combinations btw.

    what is the full drive train build?

    and you may just need to adjust the tension in the cable a bit as it has bebded in.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • John C.
    John C. Posts: 2,113
    Is it a triple ?

    If so then use the big chain ring with the smaller cassette sprockets the middle you should be OK with all the cassette and with the little chain ring just use the larger rings on the cassette.

    Also give the rear mech a good oiling it may not be tensioning properly
    http://www.ripon-loiterers.org.uk/

    Fail to prepare, prepare to fail
    Hills are just a matter of pace
  • Nuggs
    Nuggs Posts: 1,804
    nicklouse wrote:
    not that good to use those combinations btw.

    what is the full drive train build?

    and you may just need to adjust the tension in the cable a bit as it has bebded in.
    Thanks for your help guys.

    I've not been trying to use small ring smallest sprocket (sorry, that wasn't clear from my post), but the other combinations should be fine.

    The drive train's been lifted from my Roubaix Elite - FSA compact chainrings and cranks, FSA front mech, 105 Rear mech, 105 shifters.

    I'll try tightening the cable a bit, although it seems a bit odd that it was only those gear combinations that were causing difficulties.
  • COVEC
    COVEC Posts: 213
    Hi,

    Have you fitted a new chain? If the block is worn and the chain is new it can cause the problems you describe, the smallest cogs on the block are where the effect would be most noticable.

    COVEC
  • is it skipping from one sprocket to another or just slipping over the teeth?
  • Nuggs
    Nuggs Posts: 1,804
    Well, I replaced the cassette and it's still skipping :(

    I'm now thinking that the SRAM Powerlink I fitted to the 105 chain may be the problem. Each time it skipped yesterday, I stopped pedalling and the part of the chain with the Powerlink had just just come past the cassette...

    I'm going to pick up some KMC Missing Links at lunchtime and see if that fixes the problem (at least they're expressly sold as being Shimano 10-speed compatible).
  • Is the chainring 'sucking' the chain on the bottom of the ring ( the chain wanting to carry on engagement after BDC ) ? If so a new chainring is needed .
    "Lick My Decals Off, Baby"
  • Nuggs
    Nuggs Posts: 1,804
    mercsport wrote:
    Is the chainring 'sucking' the chain on the bottom of the ring ( the chain wanting to carry on engagement after BDC ) ? If so a new chainring is needed .
    I don't think so - the chainrings have less than 1k miles on them and it's only skipping on the smaller rear sprockets, regardless of whether I'm in the small or large chainring.

    I'm (really really) hoping the KMC Missing Link will sort me out...
  • I am new to MTB ing and was sorely perplexed when my 'gears' skipped. Soon found out I had a chain with a tight link. Only noticed the skipping in the gears similar to yours.

    :D
    Tall n skinny