Yeah, but a half-season for a your inner ring is like several lifetimes for other grannies. If I was to be reincarnated as an inner ring, I'd be horrified if destined for your Tetra!
Thanks for the tip on the Salsa 28t. We've not had any problems with our TA 30t, but maybe things are different with a 28t. That is throttled.
I'd like to have a 28t inner ring, but it is shifting very well now, and I think this would necessitate switching from a 42t to 39t middle, and I fret that this would degrade the middle to outer (53t) shifting. I'll let you go first!
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.
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.
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.