Haven't really noticed a huge difference in gas consumption really... I mean, maybe 10-20 miles less an entire tank? I dunno - that's just a really rough estimate...
In other words, if there is less mileage per gallon as a result of the tires it hasn't been that noticeable.
MOAB!
-biju.
p.s. tom: i think i still owe you four dollars or so from Moab this year...