44 miles per gallon? Are you sure that isn't 44 Kilos per gallon. My wife drives a 2003 CR-V and she gets about 23-24 mpg which would equal about 39 Kilos per gallon. Likewise 44 Kilos per gallon would equal about 27 mpg which is a little more believable. Her 2003 CR-V is also all-wheel drive, so I imagine it gets a little less mpg than the 2-wheel drive model.

They might have a Honda Civic (not CRV).

Having a Civic as opposed to a CR-V would also explain (1) why the poster thinks it's peppy, and (2) having one from model year 1990. The CR-V has many virtues, but I've never thought peppiness was one of them. Also, Honda began production of the CR-V for the 1996 model year.

Lets pretend you have the X model that came with 215/75/15, you could jump to 225/75/15 with out the lift kit and baelry notice any difference in mpg and won't have an effect on the drivetrain .. and the one step up is an optional size form the factory. If you had the Rocky Mountain Edition, it came from the factory with 30 9.50/15 if you have a 4 cylinder jeep, it will bogg the engine down and have worse fuel mileage. the 6 cylinder is a bit more forgiving. If you want to put some 33 12.50 or bigger, you are going to start getting worse fuel mileage and speedometer will be off quite a bit. Drivetrain on a 4 cylinder will think about busting u-joints with the 35 tires and the pinion angle will need to be reset to avoid it from happening. So I would not go too big or you will have an issue. going from 215/75/15 to 31 10.50 with a 6 cylinder shouldn't cause any problems. A four cylinder will not like the larger tires.