I ran 235's for a long time and run a very similar setup to yours. I'm much happier w/ 31's off-road, especially in the rocks, but it's primarily for wheeling. We've got two other cars for daily drivers, and I'm in my work truck for most daily driving. Tracker is a bit of a dog on pavement (2.0, auto) above 60. Last time I checked in very mixed driving (freeway to my sis' place in Vegas, some driving round town, mostly off-road coming home) I was still averaging about 20 mpg. Not spectacular, but you wouldn't get that kind of milage in a full-size 4x4 truck.