Originally Posted by
soma5
According to Sheldon Brown, they will index with the 9sp Dura Ace rear derailleur if you use the alternate cable routing. Shimano tech docs agree. I am currently running 8sp DA brifters with a 9sp DA rear derailleur with the alternate cable routing and it works perfectly. The 9sp derailleur seems to be a superior design as well.
-soma5
I used Shim 600 brifters with a DA 7400 RD, and it worked fine on 8-sp.
I used DA 7400 8/9 sp bar ends with the same DA 7400 RD, and it wouldn't work on a 9-sp cassette.
I simply switched to an 8-sp cassette, and the combo works fine.
How would simply changing the RD make a difference to the shifters as far as 8 or 9 speeds?