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I have a hybrid 18 speed bicycle which is able to shift through all gears on both the front and rear sets of gears. When on the largest gear on the front set (by the pedals) the chain will try to slide to the next smaller gear when pedaling backwards. It is as if the chain in bent or not moving in a spot.

There is also a cyclical click when pedaling forwards in higher gears with an occasional slip. It seems the chain may be uneven in several links.

What is the most likely cause/fix for this?

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    On a standard derailleur-style bike you shouldn't pedal backwards. As to your problems when pedaling forward you may have some bent or "stiff" links, or the derailer may need adjustment.
    – Daniel R Hicks
    Commented Mar 15, 2016 at 23:24
  • When riding I don't normally pedal backwards except maybe to slightly adjust the position of my feet. I thought that may be a possibility but was unsure if it was more likely to be something else
    – John
    Commented Mar 15, 2016 at 23:38
  • If you pedal backwards more than maybe 1/4 revolution, the chain will very likely "bunch up" and try to tie itself into a knot. Not all bikes do this, but probably more than half.
    – Daniel R Hicks
    Commented Mar 15, 2016 at 23:40
  • Possible duplicate of bicycles.stackexchange.com/questions/280/…. If it's, look at my answer there.
    – Alexander
    Commented Mar 16, 2016 at 0:45
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    Give all the gear/shifting hardware a good clean and lubricate. Pay particular attention to the rear derailleur. When all is clean, check the adjustment on both derailleurs. A brand new chain should be nicely lubricated already and shouldn't have stiff links.
    – Chris H
    Commented Mar 16, 2016 at 6:40

1 Answer 1

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This sounds like a stiff or separated link in your chain. There are other options, but this would be easy to eliminate, and a likely cause.

Get off the bike, and very slowly pedal backwards while looking at the chain as it passes through the rear derailleur.

A stiff or broken link should jump as it goes through the derailleur.

If the chain starts to come off the gears, check the chain at the point where is is coming off.

Most likely, you will need to replace the chain. If the chain is new, the link where it was joined may be the issue. In that case gently flex the chain side to side (against the link plates, not in the direction they pivot) at that point and it may free the stiff link.

If not, replace the chain, taking care to join the links more carefully this time.

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    A lot of folks are unaware that most modern chain tools have a "de-stiffening" feature, allowing the joined chain to be moved to a different set of "fingers" on the tool, such that very slightly tightening the screw against the pin will loosen the joint.
    – Daniel R Hicks
    Commented Apr 2, 2016 at 19:32
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    True. It is often overkill, though, especially in the hands of someone without experience using it. Too easy to push the pin too far in to the plate, and since many newer chains use a larger diameter replace,eat pin to join the chain, if you push it too far, you can make the chain useless, and have to replace it. Flexing the chain does the same job, without the (relatively small) risk.
    – zenbike
    Commented Apr 2, 2016 at 22:59
  • The far bigger risk is when breaking the chain in the first place.
    – Daniel R Hicks
    Commented Apr 2, 2016 at 23:26

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