Identifying Shimano Brifter models
I have "Shimano 105" brifters shifting 9sp rear, front triples. They do not have a trim capability. I have a Shimano tech sheet that came with the bike (new-in-box), identifying them as either ST-5500-CA, ST-5510, or ST-R600. The sheet shows a trimming capability for double front derailleurs (FD-6500, FD-5500, FD-5501), but none for triples (FD-6503, FD-5503, FD-5504). This is the first problem. Isn't the trim function in the brifter? I mean, the number of clicks and so on. But the instructions act like it is a completely different operation depending on the front derailleur. This doesn't make sense to me.
Secondly, is there any way to actually identify the Shimano model numbers on these? I haven't started looking too hard, so be nice, but what is the difference between all these?
I pulled another spec sheet off the Shimano site last year and it is for ST-5600 and ST-R700, and clearly describes trim on a triple, with no silliness about what derailleur you have. Did I just miss the boat here? Newer ones have it, older ones don't?