Quote Originally Posted by GLC1968 View Post
What, why? I have an Ultegra triple and I've not only never dropped a chain, but I often use all 10 gears in the middle ring. Oh wait...I only have 9 gears. Maybe that's the difference? I forgot that mine's a couple of years old.
Whoops, I mis-read it. Sorry. It's only the youth gearing combinations on the CS-6600 (14-25, 15-25 and 16-27) that they say not to use with a triple.

It doesn't say anything more specific than a black-box warning that "gear shifting performance will drop, and a bicycle may fall over and serious injury may result."