Results 1 to 8 of 8
  1. #1
    mtbr member
    Reputation:
    Join Date
    Apr 2007
    Posts
    484

    New chain. Skipping.

    Hi - I just installed a new chain on my bike. It now skips badly (basically under load). Is a worn cassette the most likely culprit (2 yrs. old, daily use)? Chainring? It's not a stiff link. The cassette does appear to have some wear, but not an extreme amount (at least to my eye). Just want to eliminate possibilities before forking over for a new cassette. Thanks.

  2. #2
    mtbr member
    Reputation: laurenlex's Avatar
    Join Date
    Sep 2006
    Posts
    565
    Yes, the old cassette has worn to mesh with the stretched chain. Now the new (shorter) chain doesn't mesh with the old cassette. The chainrings might be bad as well.

  3. #3
    mtbr member
    Reputation:
    Join Date
    May 2006
    Posts
    258
    Chain stretch is usually the first indicator that this sort of thing will happen. Replace your chain when it starts to display chain stretch symptons and that way you don't end up having to replace your entire drive train. When I was a total noob (note I am still a noob), I did exactly as you have done. I eventually had to replace the front cranks (worked out cheaper than getting new chain rings), cluster, bottom bracket (it developed play) and pulley wheels (already forked out for a new chain by this stage).

    I have a simple test for chain stretch (and maybe chainring wear). I set up my gears so that the chain is on the largest chainring and on a gear that will keep the chain reasonably straight. I look for any gaps between the chain and chainring (helps to have a bright light behind it). Your chain should fit snugly around approx half of the chain ring.

    If there is a gap, then the chain is not contacting properly at these points, and the links that are contacting are going to be carrying the load of the others (which accelerates drivetrain wear). My chain was so badly stretched that it was only contacting on a quarter of the chain ring (about 4 - 6 links).

  4. #4
    mtbr member
    Reputation:
    Join Date
    Apr 2007
    Posts
    8
    A new chain skipping can be explained by more than just chain wear. Its possible that the chain has a stiff link. Look very closely at the derailleur pullies as you cycle your chain to see one. Also, all the think oil on your new chain could effect the meshing with your gears. Clean the chain in a solvent tank, or cycle it through a chain cleaner multiiple times, then rinse and apply a real chain lube, like Rockn'Roll. Also, there's the possibiility your derraileur simply needs to be adjusted. If your gears are actually worn, and you simply do not have the money to replace your whole drivetrain, do your best to clean the gunky oil of the new chain, adjust the shifting to perfection, and ride at first. If the gears are only mildly worn, the chain might just set in.

  5. #5
    bi-winning
    Reputation: rkj__'s Avatar
    Join Date
    Feb 2004
    Posts
    11,137
    Replace cassette. if it still skips, you probably need to replace at least one of the chainrings. The middle is likely the most worn depending on what kind of riding you do.

  6. #6
    Currently un-unemployed
    Reputation: Unemployed_mechanic's Avatar
    Join Date
    Apr 2007
    Posts
    134
    Quote Originally Posted by capnstem
    Chain stretch is usually the first indicator that this sort of thing will happen. Replace your chain when it starts to display chain stretch symptons and that way you don't end up having to replace your entire drive train. When I was a total noob (note I am still a noob), I did exactly as you have done. I eventually had to replace the front cranks (worked out cheaper than getting new chain rings), cluster, bottom bracket (it developed play) and pulley wheels (already forked out for a new chain by this stage).

    I have a simple test for chain stretch (and maybe chainring wear). I set up my gears so that the chain is on the largest chainring and on a gear that will keep the chain reasonably straight. I look for any gaps between the chain and chainring (helps to have a bright light behind it). Your chain should fit snugly around approx half of the chain ring.

    If there is a gap, then the chain is not contacting properly at these points, and the links that are contacting are going to be carrying the load of the others (which accelerates drivetrain wear). My chain was so badly stretched that it was only contacting on a quarter of the chain ring (about 4 - 6 links).

    Unfortunately, chain "stretch" doesn't really show any symptoms until it's too late. No offense, but I prefer chain wear or elongation to avoid confusion, since the chain isn't actually stretching, but the pivots wearing out.

    Checking for gaps around the chainring teeth is also a better indication for how much the chainring has worn, not really the chain. The best way to measure chain wear is with a ruler or one of the many wear guages available. The rule of course is to measure 12 links (I define one link as the full set of outer and inner plates joined by one rivet) from the end of one pin to the end of another along the bottom run. A new chain is usually close to 12"; a measurement close to or at 12 1/16" means replace promptly; beyond that, the cassette has probably seen significant wear and should be replaced and the most used chainring (often the middle) may have light to moderate wear.

    Also, since chains and gears wear together, a chain the works ok on a moderately worn out cassette or chainring will have a shorter lifespan. Replacing the chain at the right interval consistently gives the best combination of chain and cog/chainring life.

    -R

  7. #7
    mtbr member
    Reputation:
    Join Date
    Apr 2007
    Posts
    484
    Thanks to all for the advice. Replaced cassette and chainrings - shifting great on this afternoon's ride. Chalk it up as learning experience - don't wait until chain etc. is completely worn down before tending to it. D.

  8. #8
    Vaginatarian
    Reputation:
    Join Date
    Oct 2005
    Posts
    5,686
    now that its all new, an easy method to check for chain wear is , measure 12" from pin to pin on the chain, if its off more than 1/16" replace the chain.
    that way you can get 3 or 4 chain s to 1 cassette or ring.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •