Interesting article about drivetrain hacks - one guy uses a 6mm spacer on the 10speed XTR RD cable pinch bolt which slightly increases the travel per click of the RD to match the 1:1 SRAM 9 speed instead of the 1 and a bit to 1 of dynasys. He claims it works fine - I was thinking of trying it out myself
One word of caution - it's virtually impossible to quantify "works fine" - a trail buddy (who is a right masher and breakks things at least once a month) is running a 10 speed XT RD shadow+ with 10 speed SRAM twisties (unmodified) and he thinks it's fine - everyone else who's tried his bike (myself included) think it shifts like S**t - rattles about and seems to take ages to catch, in the low gears - It's his bike I want to try this on - smaller spacer than 6mm though
I had to make a shim to make it work properly. You can see my picture under the sticky on the subject at the top of the drivetrain forum. Dated 4/2/12 about 16 pages in. Some folks said you did not need to do anything but I found that this was not the case as the pull ratios did not match properly. Can't take the interweb as gospel don't cha know. I am very picky about shifting so I developed a solution for my needs.
I too have friends that mix-n-match components and say stuff works. I hate riding with them as they really only can use only a few gears as the rest are ching and skip. They are happy so good for them. Everyone has different expectations so I understand.
I am. I had to make a shim to make it work properly.
I've been using this setup for a few months and it works great. My drivetrain shifts just as precisely as before but with far less chain slap. I made a spacer similar to Stevoo's (thanks Stevoo!) and switched out my 9-speed X9 RD for an XT 10-speed Shadow Plus RD. Everything else remains 9-speed. Shifters are 9-speed X9 triggers.
Setup a M986 XTR Shadow Plus 10-speed rear derailleur with a SRAM X0 9-speed shifter on a new hard tail build and it shifts quite nicely. I used a 6mm shim. The primary reason is that I have a lot of 9-speed gear that I want to continue using (for a lot of reasons) and wanted to eliminate chain slap in style