IN regard to Ryan (OP) question my feeling is that Lexus sold us their version of a specialty tire with a weak sidewall and a good ride quality. when you buy your new tires the game changes. Most SUV tires will be a stronger construction and a little stiffer ride. LT tires will be a lot stronger and even stiffer ride. Yes the 18 inch will have more flexibility than 22 inch. Play with the tire pressure to improve ride no matter which tire you like. Also play with the tire pressure when going off road. I feel the sidewall strength is important as it stays strong no matter the tire pressure you need. My 2 cents.