I know haha. Basically, you can run a sram 9spd shifter on a 10spd shimano mech. The pull ratios are very close to each other. It'll work ok without any modifications, but to alter the pull ratio so that it's perfect, you can put a 6mm washer underneath the cable mount. Then the ratios are pretty much identical, and it'll work perfect
It's just a way to save me from unnecessarily replacing my perfectly fine 9spd cassette, shifter and chain at the moment. Oncwe the cassette and chain are too worn to use, i'll swap out the chain, cassette, and shifter for a 10spd setup
hmm, interesting! I will be setting mine up on a 6 speed cassette later today (10 speed - 4 cogs) and I'm hoping I can run a little bit shorter of a chain to keep some more tension.