9 speed shimano cassette and chain, 11 speed xt shifter mated to xt m739 v brake levers, stainless single speed chain ring and 10 speed Zee derailleur. In true franken form it doesn't work perfectly, the largest cog needs a double shift to push it over the line, but everything else works fine.
Inspiration from Hucking Kitty
Edit: The best resource for figuring out all the combinations and permutations is Science Behind the Magic | Drivetrain Compatibility – Art's SLO Cyclery
Woah, woah, woah!
A: how can an 11 speed shifter work on 9 speed?
B: how did you attach the shifters to the levers?
I have a couple of modern bikes running 11 speed. Perceived wisdom (of the internet) is that 11 speed chain should be changed at 0.5%, therefore I have spare part-worn expensive 11 speed chains….. perfect for a beater bike build! So the reason is that I’m a cheapskateQuestion - why would you want to run say an 11 speed chain with a 9 speed cassette? How does all that bed in?
An 8 speed cassette with a 9 speed chain OK, the internal width is the same.
Because I threw a 10 speed derailleur in to the mixA: how can an 11 speed shifter work on 9 speed?
Short answer: dremel.B: how did you attach the shifters to the levers?