Chain Ring Shifter Issues

[ForwardGhoul]

Does anyone know why all of a sudden my chain ring shifter has all of a sudden stopped working. When I try to shift down to the granny ring it won’t move at all. I usually am on the big ring anyway but the climbs are a ******* without the small ring

[Cyclothesist]

Lots of reasons. One is that the cable has frayed in the shifter and jammed the downshift. Some photos of the front derailleur and the shifter would help.

[Brucey]

probably the mech is a bit corroded/seized and/or the return spring isn't working. Often, if corrosion is the problem, normal function can be restored by simply spraying the FD with a penetrating lube, and then 'exercising' it, if necessary pushing it with your thumbs. In the long run, more cleaning/lubrication isn't a bad idea, especially if you don't have mudguards.

[geomannie]

What you describe is a very common problem in older bikes that are well used, but the rider has a preference for the bigger ring(s). As Brucey says, almost certainly bunged up with road dirt & corrosion.

Brucey's suggestion is bang on. Lubricate and work the lubricant in by manually pushing and pulling on the derailleur. Give it a good brushing and cleaning too.

Sometimes, if very seized, it's easier to remove the derailleur and hold it in vice while pushing & pulling.

To keep it sweet in future, shift into your small ring reasonably often use mudguards.

[peetee]

It’s also possible that the shift cable is gummed up or frayed inside the lever.
The easiest way to find which is at fault is to disconnect the cable at the front mech. If it’s the shifter at fault the front mech should immediately drop to the granny ring position. If it doesn’t then follow the advice described in previous posts.

[ForwardGhoul]

Thank you to all who replied.

Yes it is an old bike, a Ribble winter bike and I adore the old girl. The common theme here with the suggestions seems to be that it’s seized and needs some lube, I’ll also check the cables as well. I don’t use the LH shifter often and I’ll try these solutions

[drossall]

The issue is probably either in the cable or in the derailleur itself. If unsure, undo the cable anchor bolt on the derailleur. If it then moves, it was the cable (probably needs replacing). If it doesn't, it was the derailleur (probably needs lubrication and/or cleaning).

[Brucey]

a good test, but if the FD moves when the pinch bolt is loosened it could be the cable or the shifter which is at fault.

[cyclop]

"I don,t use the left hand shifter..."? so just remove the front mech and have done with it.

[drossall]

a good test, but if the FD moves when the pinch bolt is loosened it could be the cable or the shifter which is at fault.

Agreed, but I was simplifying. It's generally the cable, and it can be hard to distinguish between a shifter issue and a cable issue in the shifter.