Bicycle Mechanics - Are STI shifters adjustable for # of speeds?

I was looking for a front (left) STI shifter to match a spare rear (right), seller on ebay told me his Ultegra is adjustable for 2 or 3 speed... is this right? And if so how do you adjust an Ultegra shifter?

Some Shimano STI brifters were double and triple crank compatible. 9-speed 105 certainly was but I don't know about 9-speed Ultegra. Anyway, you don't "adjust' the brifter but it is controlled by how you hook up the cable. Shimano's tech document describes the methods.

Some Shimano STI brifters were double and triple crank compatible. 9-speed 105 certainly was but I don't know about 9-speed Ultegra. Anyway, you don't "adjust' the brifter but it is controlled by how you hook up the cable. Shimano's tech document describes the methods.

Correct. You can set up a triple brifter to control a double but not vice versa.

Correct. You can set up a triple brifter to control a double but not vice versa.

+1
But in 9-speed the same Ultegra left shifter is used for doubles and triples.

Thanks for your replies. I read the tech docs for a couple Shimano STI shifters but there is no mention of adjustments for different # of chainrings.

Would it suffice to just adjust the limit screws on the derailleur?

http://techdocs.shimano.com/media/techdocs/content/cycle/SI/Ultegra/SI_6K20A_001/SI_6K20A_001_En_v1_m56577569830616322.pdf

The original 5600 10-speed 105 shifters were double/triple compatible, but there were lots of reports of the left shifter breaking when forced to shift in a double setup (this happened to me - Shimano is aware of the problem and contacting them can get you a new set of shifters if you ask an LBS to send it back to them). Sometime in the lifecycle the 5600 shifters were redesigned, and came with specific "double" or "triple" markings on the left shifter. I believe the part numbers are ST-5600 for "double-triple compatible" and 5601/5603 for double/triple, respectively.

I own a 9-speed Ultegra equipped road bike and a 9-speed Ultegra equipped tandem. The road bike has a double chainring, the tandem is a triple. Both bikes use the same shifter that has 4 shift positions. The cable routing and connection to the derailleur for both bikes is identical.

On the double I get 2 shift positions for each chainring. The triple has one position for the granny, 2 positions for the middle ring and 1 position for the big ring.

Both bikes have Flight Deck computers which always indicate the correct chainring so I'm sure derailleurs are set up the way that Shimano intended.

Actually with 9-speed Ultegra there are 2 available positions for each of the rings on a triple. From the small ring position there is a soft click trim position, then two positions for the middle ring, and one for the big ring. But the second position for the middle ring can be used for trimming the big ring.