problem with shifter?

jimycooper

At some point in the last few weeks, ive realised that my (campagnolo) shifter doesnt click up or down a gear, but has started just feeding more or less cable to change gear.

This has caused the gears to start jumping slightly, and not being dialed in, so making me have to press the shifters slightly to get the rear mech in line with the individual sprocket i want.

Does anyone know what the problem is?

any advice is much appreciated as soon as possible because im going to race in belgium next weekend and need it sorted!]

cheers

ex-pat scot

Sounds like the shifter is working OK (if it is feeding cable in / out), but the problem lies with stiffness either in the rear mech pivots (less likely) or stickiness in the gear cables (more likely).

Put the bike on a bike stand (or otherwise get the rear wheel off the floor).
put the rear in smallest sprocket with the shifter and the front in the small ring (or middle if you have a triple).

turn the pedals and push the parallelogram part of the rear mech (the bit with the writing on) to manually shift to the larger sprockets. How does it feel? Is there some resistance (there should be, as there's a return spring). Can you do this easily with your thumb, or is it really difficult?

next do the same thing, but by pulling the rear gear cable where it sits free at the downtube. Again does it feel very stiff? If it is noticeably stiffer than when you tried the above shift (thumb on the rear mech) then this suggests excessive friction in the cables.

If neither, then it could well be a shifter problem.

Remedy.

1. inspection of gear cables.
You should be able to disconnect the front end of the rear mech cable outer (where it connects with the chainstay). Have a close look at the inner for frayed ends, especially in the area around the bottom bracket and inside the rear section of outer cable (you'll obviously have to slide the outer along to see this bit).

2. inspection of outer cable.
does the outer cable look rusty, worn, cracked or does it go through a sharp bend before entering the rear mech?
does the front section look kinked in any way where it bends before entering hte down tube stops?

3. penetrating oil on the rear mech pivot points. Give the rear mech a thorough clean.

4. (possibly.) Some advocate lubing the inner cables. Some don't. I do.

In any event, it's worth regularly replacing gear inner, and the rear section of outer cable.
Make sure there are metal ferrules on the ends of the outer cables.

Personally, I doubt from your description that there is a shifter issue. I certainly hope not, as they are complex beasts...

jimycooper

Thanks for your reply.

The shifter wasnt too hard to push up with thumb, but the gears were jumping a lot.

The cable method wasnt much harder, and all of the cables look fine when i inspected them.

I cleaned out the mech and oiled it, but it made no difference.

I think a trip to the LBS may be in order

:roll:

thanks again

ex-pat scot

Another thought- how worn is your chain? That may be the cause of skipping gears.

I presume when you said "The shifter wasnt too hard to push up with thumb" you actually meant the rear mech!

jimycooper

recently changed the chain a few weeks ago so i doubt its that.

yes, my mistake

ex-pat scot

Ah!
New chain plus old sprockets. May well be the source of skipping gears.
Did it skip before you changed the chain?

That'd be my diagnosis

jimycooper

yes it did, thats why i changed the chain

just took it into the shop, and the guy thought that the shifter was knackered and it wasnt holding tha cable firmly enough to stop the cable from moving a bit.

so he suggested a new shifter

ex-pat scot

jimycooper wrote:

just took it into the shop, and the guy thought that the shifter was knackered and it wasnt holding tha cable firmly enough to stop the cable from moving a bit.

so he suggested a new shifter

Not heard that one before!

jimycooper

:? really. i may have mis quoted him, to be fair. seemed like a sound explanation at the time...

thanks for the help anyway mate

desweller

TBH shifter faults are almost the last thing to check after cables, cassette and derailleur maintenance. Compared to these items, shifters are well protected from the elements so they're pretty unlikely to wear out. As a guide I replace the cables in my road bike every year.

The ratchet surfaces and pivot pins in shifters are very hard and take a long time to wear, so if the performance of the shifter has deteriorated, chances are it's down to contamination. If it has become contaminated, a protracted blast of WD40 in there wil clean it out.