3x7 shifters on a 2x7set up

[widowmaker]

Just a quick question.

I have a roadbike with a 2x7 set up and I am swapping over the downtube shifters for STI's but they are 3x7, am I right in assuming I can use them, in the front big cog the first click would select the small cog and the last click would be a ghost ? one ?

The adjustment screws on the front mech would stop the chain falling of ??? :?

 

[The History Man]

The firs click would select the large ring. The second cluck should be stopped from happening by the mech adjustment.

Edit. Firs cluck?

 

[widowmaker]

The firs click would select the large ring. The second cluck should be stopped from happening by the mech adjustment.

Edit. Firs cluck?

Bingo, that's what I thought. Had a test ride and the chain came of a few times :facepalm:

Pops out to shed with screwdriver !