Acera 7 speed shifting advice needed

[oonaff]

Hi there chaps! ive been using m daughter's kona to commute to work at the mo
whilst she is in barcelona.
the problem is the right rear cassette thumb shifter only shifts rmech half way along
the cogs even with 2 full pushes.rear mech is set ok with non tension to small sprocket.
is the thumb shifter worn out ?
thank i a kevin

 

[joss]

Re:

If the cage can move freely from large to small cog and reverse with manual pressure and the cage does not hit the spokes when on the large cog it is probably in its original set position.
Which means, firstly the problem is the tension of the cable may have slackened off over time, secondly that cable has slipped on the cage retaining bolt and that the cog to shifter alignment is incorrect, this pre-supposes that the cable was set up correctly, thirdly there is a problem with the shifter sticking or restricted.

Cable tension is the most common cause, grab the cable, usually under the down tube, and pull down whilst turning the pedal, if the cage shifts the full distance, using this manual shifting, the problem will be tension. Loosen the cage retaining screw/bolt and slacken the cable, reset with the chain on the small cog and highest gear on the shifter and reset the tension and lock off.

Everyone has a different method, but in my experience look for wear and tear and tension of cable first.

A squirt of plusgas in the shifter can work wonders.