Originally Posted by
gsa103
Nope. It would work as an 8-speed cassette, but why you'd do that is beyond me.
Here's a much bigger chart with all the numbers.
Art's Cyclery Blog » Science Behind the Magic | Drivetrain Compatibility
We can take the pull distance and the cog pitch as givens, because they are relatively easy to measure.
A 9 speed SIS derailluer has a cable pull of 2.5mm and a pitch of 4.35mm, so the derail ratio is 1.74.
An 11-speed road shifter has a pull of 2.7mm. Used with a 9-speed SIS, gives a cog pitch of 4.7mm, that's definitely way too large.
Interestingly, an 11-speed SRAM road shifter paired with a Shimano Dyna-sys RD or 10-speed SRAM RD, would probably work with an 11-speed mountain cassette. Just an interesting option for the low gear crowd.
It should work.
Also, SRAM 1:1 standard, with RD movement ratio of 1.1 mm is the same as Shimano 11 speed road RD movment ratio. Anyone tested compatibility (11 speed Shimano road cassette and shifters, with 1:1 RD)?