While riding yesterday I could shift into the big chainring, but to get back to the small chainring, I had to dismount and press on the chain with my hand (I'm not talented enough nor inclined to learn how to do this with my shoe while riding). It's an eight year-old triathlon bike and there was plenty of slack in the cable when I tried to shift.

What could be wrong?

  • You need to adjust your front derailleur, or take it to your LBS and have them do it. Most common cause is improper cable tension. Could also be the derailleur alignment/setup. Also, if the spring is worn out you may have to replace the derailleur. Sometimes if your chain isn't clean it can stick and you'll have a hard time shifting in general. When was the last time it was serviced?
    – ebrohman
    Jul 12, 2015 at 13:10
  • @ebrohman I had it serviced less than a month ago. It came back with the handlebars off by about three degrees to the left.
    – IronMensan
    Jul 12, 2015 at 13:18
  • If there was slack in the cable (and you have typical front derailer which springs inward) then the derailer is frozen/misadjusted or the cable is stuck. The first thing to check would be the "low limit" -- back out the "L" screw on the derailer by about a half turn. Jul 12, 2015 at 13:31

2 Answers 2


The derailleur was sticking. A bit of lubrication and all was good again.


This is not that uncommon on mountain bikes. Many times a small pebble or trail or road debris is picked up by the tire and deposited in the pivots of the derailleur. It will sometimes dislodge if you shift onto the biggest ring. Other times you have to remove the object it by hand.

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