I am using 21 speed bicycle and the problem is that I am unable to shift the chain to the largest derailleur(rear)....the shifters are thumb press type there's no problem in pressing the shifter...when shifting to the 1st gear the chain shifts up to 3rd derailleur(rear)!

  • 1
    Have a look at bicycles.stackexchange.com/q/26062/19705 sounds like your gear inner cable has stretched and needs minor adjustment. Do be mindful of putting the cage into the spokes by mistake... that's not right.
    – Criggie
    Jan 15, 2017 at 19:09
  • Usually this just means that something (probably the cable's "barrel adjuster") needs adjustment. But sometimes the problem is more elusive. Jan 16, 2017 at 1:49

1 Answer 1


A stretched cable is one possibility. Has the cable been replaced recently? They stretch most when they're new.

A second possibility is that you removed the rear wheel and when you put it back on, didn't get it seated the same as it was before you took it off. That could change the position of the derailleur enough to make it impossible to shift onto the largest or smallest gear in the cluster.

A third possibility is that you need to adjust the high-low limit screws on the derailleur. Here's what Park Tool has to say about that... http://www.parktool.com/blog/repair-help/rear-derailleur-adjustment

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.