Originally Posted by
Niloc
Hmm, I've discovered an interesting feature about the XT shifter: there's a means of adjusting the positioning of the shifter unit on the mount that clamps to the handlebar. It can be mounted in one of three positions, as indicated by a little arrow pointing down at three machined dots on the handlebar clamp. You can see these in the attached photo. Do you suppose this feature provides a means of adjusting the amount of cable pulled and therefore what cog spacing it will index with? I can't figure how it would do that but then I'm not as clever as Shimano.
Perhaps it just provides a way to tweak the position of the shifter lever on the handlebar for user preference / ergonomics. The left hand shifter for the FD, which is friction only, also has this feature.
Thanks for your input - Colin
As you surmised, it was a way to adjust the position of the lever relative to the handlebar. 6-speed shifters worked with 6-cog cassettes or freewheels, 7-speed shift levers worked with 7-cog cassettes or freewheels. Shimano did all sorts of things in that era, but you had to match the shift lever with the number of cogs.
(FWIW: I worked in the industry back when those were new. All your questions were asked back then, and the answers have not changed. Mostly.)
I'm pretty sure the IRD freewheels are built to match the "standard" (aka not-Ultra) spacing, which is to say they would work with your 6-speed XT shifters.