sjpitts 

I helped a friend put a pair of those new ultegra brifters on a Trek Madone. They seemed pretty cool. No funny cables coming out the sides.

It made me wonder how they might work on an older bike, with say shimano tricolor 6400 brakes and derailleurs. From what searching I did it seems like shimano is saying that the brakes are not fully compatiable. Like they use different pull rates or something.

I didn't find anything with regard to the front or rear derailleurs. My best guess is that the RD might be ok, but I have no idea on the FD.

Jared

Puget Pounder

RD and FD should be fine. I've done pairings that go the opposite direction. Ultegra 6700 derailleurs with RSX shifters and it worked perfectly. Not sure about the brakes, but I think it should be fine. If you can cross between brands, then that combo should work. Think about Tektro brakes. They work with any brand of levers.

Don't take my word for that last bit though!

Puget Pounder

I also have a 6400 derailleurs mated to Tiagra shifters on a bike right now too.

pastorbobnlnh 

I have Sora 7 speed STI shifter/levers running a Campagnolo Centaur long cage RD, a Sora triple FD, and modern Centaur brake calipers on a Suntour Winner freewheel. Interestingly, the Campy Centaur FD would not work with the shifters. Bolt what you have together and see if it will go.

RobbieTunes

I think you'll be fine. I'm running 6500 STI's on a C&V bike, and I think drrobwave is running 6700's on his '93 Miyata Team Carbon. It's ace.

As far as the calipers, I haven't found too many problems with anything modern from SLR caliper, to date, with any STI lever. The only problem I've seen is some rub on certain Tektro calipers that have less clearance, for some reason.

gmouchawar

I did encounter a problem with braking performance when I switched by from '86 Shimano 600 brake levers to 7sp STI.
I ended up buying new Tektro dual pivot brake calipers to restore and improve performance.