Originally Posted by
cpsqlrwn
Looking into some Shimano down tube shifters and want to know whether Dura Ace 7402 (8 spd), 600 6400 (7 spd), and 600 6401 (8 spd) down tube shifters perform in pure friction mode or produce a click ratcheting action when set to run in friction mode.
With the original SIS index shifters, you switch between indexed and indexed and friction mode by rotating the D-ring on the lever:
There's about 90° of travel between full indexed mode and full friction mode, and if you set the ring in between the two end points, you get varying degrees of indexing, from a pretty solid "click" with each shift to a subtle bump before the indexing completely disappears.