Originally Posted by
reptilezs
the 6700a mid cage rd is 30t max cog size. the older 6700 mid cage is the same 28t max as stated in the first post
And I misspoke. Or mis-typed. I went out and looked again at the box that the new RD came in. It's marked "6700-A," which means it accepts a 30-tooth rear cog, as also noted on the box.
And that, probably more than anything, explains the better shifting. So if you're running a 12/30 in the back and a standard (53/39) chain ring up front, this might be the RD for you. Best. DB