Front Mech Not Moving

narbs

Hi

My 105 front mech is stuck in the big ring. The cable under the downtube is taught but both shift leavers seem to be in free fall - no clicking and the mech doesn't move.

Does anyone have any suggestions on fixing this?

Cheers.

robbarker

When did you last change the cable? That's the most likely cause. Fit a new one and see if it solves the problem.

It could be that the shifter ratchet has gone.

narbs

robbarker wrote:

QWhen did you last change the cable? That's the most likely cause.

It could be that the shifter ratchet has gone.

Had a full cable change in June, so hopefully not that!

robbarker

In that case be clearer about the symptoms.


What do you mean by free fall? You try to change down and nothing happens?

Do you really mean both levers? Is the rear mech stuck in the same place too?

How old and what mileage are the shift levers? Used through the winter? How much maintenance?

How much riding have you done since the new cables in June and in what conditions?

Try disconnecting the cables fromt he mechs and see if the racthets on the shifters are working properly - you can do this by gripping and pulling the cable while operating the shifter. You can also check that yhe mechs themselves move happily between their limits. I've come across a few seized front mechs and I'm sure rears are more than capable of it.

Make sure your inner cables can move smoothly through the outers - that's still my main area of suspicion.

If the shifters are knackered, it's not going to be as cheap as new cables. I didi fit new inner guts to Ultegra STIs once, but the parts are hard to get hold of. If it is the shifters, speak nicely to your lbs and see what they can do for you.

narbs

Thanks Rob.

Yep, when I try to chage down nothing happens - there's no friction on the inner lever which goes to about 45 degrees and the outer lever runs to about 30 degrees, again with no friction or clicking.

I've released the cable and reattached and no change.

I'll book it in to the LBS I think.

Monty Dog

Unlikely to be the cable from the sound of it and more likely the shifter - which is failing to release. Pull back the rubber lever hood and make sure that nothing is jamming the mechanism e.g. hood fitted incorrectly / frayed cable end. There is a spring-loaded pawl that it sticking in position and not engaging with the release lever. Try a good squirt of WD40/GT85 inside to see if it clears out any muck or debris and see if some coaxing with a small screwdriver can get the mechanism to move - but be careful, there are some tiny springs in STIs that don't like any attention! If still no joy, try your LBS but knackered STIs don't offer much scope for repair and a new lever is probably in order. Ebay is a good place for single levers as spares are £80 plus new.