I went with SRAM components
I went with SRAM components that their website said was compatible, e.g. my
X9 TYPE 2 RD states it is 36T compatible. Here and various other places I found statements that said their road brifters would work with their MTB RDs.
My choice for an 11-36 cassette with a full 53-39 double came about by reading about Dan Fallon's experience in the Arizona mountains and comparing the gear inches and gain ratios of my old MTB triple values to determine what I ended up getting.
I tried to get as close to the low end as my old MTB but a lot higher on the high end. Originally I had done the comparison playing with the calculator on the Sheldon Brown site but then Charles Plager pointed out the Mike Sherman one which I like a lot better.
Here is my
Vendetta configuration and my old
Diamondback Ascent MTB configuration.
If you have a triple + cassette combo that works for you, playing with the Mike Sherman calculator (or similar) makes it easy to figure out what double + cassette combo might come kind of close to what you want.
For myself, I generally never used the very lowest gear combinations on my MTB but I wanted to get close to the the lowest in case I found myself slogging mile after mile after mile uphill like Dan does.
Similarly, I was always running out of high gearing on the MTB and wanted more gearing on the Vendetta so I could still pedal and continue to develop power at much higher speeds. Hence my choices. So far I'm very pleased with the result. I'm particularly happy with the X9 TYPE2 RD. The clutch seems to eliminate chain slap and the cage lock is a true blessing when it comes to dealing with the Cruzbike drivewheel.
The other thing you need to watch for is the jump between gears - you may find your uber range setup always leaves you hunting to go a little lower or a little higher because your gears are now spaced wider than you usually have on a road bike. I get a little of this depending on the terrain but for me it actually feels pretty comfortable. If it was just tolerable I'd probably switch back to a tighter cassette or try going with a Rohloff or NuVinci setup.
It looks like that X-DOME is only compatible with the rest of the XX1 stuff which appears to be just a single crank ring up front with a range of sizes to choose from (28-30-32-34-36-38) and is supposedly easy to change without removing the crank arm. The cassette also requires their special XD driver body and the XX1 RD. Plugging in the cassette numbers along with a single 38T crank into the Mike Sherman calculator gets you a bottom gain ratio of 1.77 but kills your top end as your top gain ratio is only 7.44. My Vendetta is 2.12 to 9.44 for comparison.
And finally, that XX1 stuff is a lot more expensive...
-Eric
