FWIW, I had the 39t (FSA) on for a while, which I installed due to the big jump from the 28 to the 42, and it shifted just fine. I switched back to the 42 when I put the crazy 55t (and 30t) on for RAAM, and just left it there when I put the 53t back. All the combos shifted fine once dialed-in.
Originally Posted by Ritterview
Another concern with the 28 is that it may rub the bottom of the FD cage, where the front plate joins the rear plate, when you move down the cassette. This may limit your cross-chaining ability before the chain length does.
I installed them just now and took a spin around the block.
53t Dura Ace 7800 outer
39t FSA triple middle
28t Salsa inner
Shifts are perfect, especially the 39t -> 53t shift.
Actually with the 6700 FD, the inner cage is shaped for a 39t middle. With the 42t middle, I always ran it in a higher position than would be ideal to avoid the inner cage rubbing on the middle ring while the chain was on the big ring. So far the 39->53 shift (with the better positioned FD) seems better than the 42->53 was.