Campy triple front shifter w/double crankset

Red Tornado

Purchased a Campy Centaur brake/shifter set on e-bay and after installing realized the front had way too many clicks to be a double shifter. I'm trying to make it work with my double crankset. Currently it overshift going onto the big ring. As I see it these are my options:
1. Adjust the LOW limit screw for just a little bit extra clearance between the inner derailleur plate and chain (effectively moving everything inboard just a bit) so the travel will be just a little less outward. Have to be careful not to go too far though, so the chain stays on when shifting back to the little ring.
2. Do the opposite of number 1, hoping the chain will shift to the big ring one click earlier and not go past. Hoping I can get it close enough where the chain won't rub too much in little ring/big sprocket combination.
3. Loosen the cable tension just slightly to take a bit off the travel for each "click" or detent to prevent the overshift.
4. Tighten the crank arm just a little bit more (while stayiong within torque spec) to move it inboard just a bit (square-taper crankst).
Shame on me for not clarifying that it was a triple shifter - just assumed most Centaur stuff was double. Any input would be appreciated.

Ian.B

Shifters are not specific to double or triple chainsets, just set the derailleur up right for your chainset

jrab

Not overly familiar with Campag, but most front shifters have a "trim" function. If the front mech is set so the chain doesn't rub it when in bottom gear, the chain will start to rub on the outside of the cage as you shift through to the smaller sprockets. As you get to this point, operating the shifter moves the mech further towards the big ring, enough to stop the rubbing but not enough to shift to the big ring. Shifting onto the big ring happens with the next click. Same thing works on the way down from top gear, as the chain starts to rub the inside of the front mech cage. This trim position will be the extra click you have.

As for option (4) you mentioned - no-go. The chainset should already be firmly mounted on the axle and should have no room to move in or out.

I think you're nearly onto it mentioning limit screws, I think you misunderstand though when you talk about adjusting the LOW screw so the travel is less outward. The LOW screw has no effect at all on the outward movement, it is simply a limit screw which stops the mech moving inwards past a certain point. If you are over-shifting off the big ring you need to adjust the HIGH screw to stop the mech moving too far out. Set up the limit scrws with the cable tension released.

Once both limit screws are set correctly for the chain at each extreme of travel then you can work on the cable tension.

Richard.

andy_wrx

Dunno about Campag either, but whilst 10sp Ultegra has separate double and triple shifters, 9sp didn't - my 9sp Ultegra shifters are running triple on my Winter bike, they came 2nd-hand off a friend's bike which was double.
And 10sp 105 doesn't have separate shifters, and I understand the problem with them breaking (see lots of threads on this forum) is that when used on a double/compact, if you force them into the extra triple position then you break them internally.

Aren't the options...?

- only use the inner and middle positions, lock the outer out at the front mech
You set the High and Low limit screws on the mech as usual so that when you shift to the big ring the chain doesn't go beyond it and fall into the pedal and when you shift to the inner ring the chain doesn't go beyond it and fall into the BB.
You put the shifter into the inner ring position and the chain on the inner ring on the chainset and tension the cable.
Now, when you click to the middle ring position in the shifter it'll give you the big ring on the chainset and then when you click back to the inner ring position in the shifter it'll drop back to the inner ring on the chainset
If you try to click again to the big ring position in the shifter, it won’t go because you’re trying to pull the cable tight but the High limit screw on the mech won’t let you pull it that tight, hence you can’t get the position.
I’m pretty sure this is how my 9sp Ultegra shifters worked when installed on my mate’s double bike.
However, what I understand the problem with the 10sp 105 shifters to be is that if you do try to get that extra position in the shifter, which is actually there in the shifter it’s just the cable tension set by the mech High limit screw not letting you get to it, then you can force it and you break something inside the shifter, knacker the thing. Presumably my 9sp Ultegra shifters were built a bit more robust...

- alternatively, only use the outer and middle positions, leave the inner 'there' but redundant
Again you set the High & Low limit screws on the mech so that you can’t overshift on the chainset and so the chain doesn't go too far and fall off into the pedal or BB respectively.
This time however, you put the shifter into the middle ring position and the chain on the inner ring on the chainset and tension the cable.
Now, when you click to the big ring position in the shifter it'll give you the big ring on the chainset and then when you click back to the middle ring position in the shifter it'll drop back to the inner ring on the chainset
If you click again to the inner ring position in the shifter it will make the cable looser but the chain can't move because it's stopped by the Low screw on the mech so it'll stay in the inner ring.
You'll have a redundant position in the shifter - you'll have to click back to the middle position and then again to the big ring position in the shifter to get the chain to move onto the outer ring on the chainset.