using a triple shifter for double chainset

[aljohn]

I've been looking to buy (cheaply) a pair of ultegra 10 speed x 2 shifters. I've just spotted a triple pair of 10 speed shifters and I thought.......
I know I can use the triple to operate with the compact chainset, but it seems so easy..... I bet I can cock it up. So, can anyone point out any flaws in my plan, or anything I haven't thought of, please?

[Threevok]

Not sure about road bukes, but MTBers have been doing this for years. You just set the front mech not to go past the point of lower gear.

Some MTB shifters (such as the SLX ones on my GT) have a switch on the underneath that actually stops it dropping down to the granny ring - changing it from a three speed to a 2 speed. Again, not sure if there is a road equivalent.

[landsurfer]

I did this on my Triban 500 when i changed the original triple chainset for a SPA Compact Double chainset.

You still have the 3 positions available on the lever.
I decided to use the top 2 positions and set the changer stop to prevent the changer moving in case I accidentally changed the wrong way ....
It worked perfectly.
Cost nothing .....

[Giles Pargiter]

No problem just set the stops suitably, as mentioned. You can even change straight to a triple when you find the range change comes at an awkward speed (especially in traffic) and you wish to try/go back to a triple

[Norman H]

You should set it up so that the redundant click is at the low end (small ring) The easiest way is to set the mech to the inner ring using the limit screw and set the lever in position 2 before clamping the cable. If you have the redundant click at the high end (big ring), there is a danger that the mech will hit the screw stop and overshift enough to jam up.

I hope that makes sense.

[Gattonero]

Just a word of advice, with Shimano shifters make sure the cable tension and FD limit screws are setup well. If -when moving from small to big ring in a double setup, the shifter starts to engage the rathet in the portion for a 3rd ring, it may get jammed.
I've seen many shifters being forced and become unusable.