Leave it to Vibrato to take a cheap shot at 29ers, it never fails.

The tightness you are experiencing may be due to the fact that the Stan's rims are generally wider, both inside and out, compared to the rims you've used in the past.

I've got the Stan's Flows on the Evolve, got the 2.4 Maxxis Ardent on by hand, popped the bead with about 7psi. Ran 'em tubeless at ~22-24lbs during "The Best Trip Ever." *Mad* traction, although I may not ride fast enough to test the traction limits ;-)

When it's all said and done, tubeless is *supposed* to allow for lower pressures and greater traction due to the larger volume of the tire...especially with the wider profile of Stan's rims. However, the pressure is all relative. In Vibrato's case, the MKs are known to have a sweet spot of around 30-32lbs when setup tubeless...compared to other tires like the Ardent, Rampage or even the Bontrager 29-3 which run in the low to mid 20's for their sweet spot (Kings has been known to run the 29-3 around 18lbs!). And since you probably don't touch north of 170lbs on a scale, you could probably get away with even lower pressures.

In all the ridiculous amount of research I've done on tires, I've read the Rampage performs very, very well when tubeless...not to say that you've had problems with tubes but comparatively speaking, it has even greater traction tubeless.

All this said, I may sound like a homer for tubeless setups but I've had my problems (Landahl, anybody?!). I have yet to convert the Truth over - running the Conti MKs - and I'm not sure I will with those tires. That said, both trips to Moab/Fruita with some of the most technically demanding terrain and I've ran tubeless without a single problem...for what that's worth.