I'm gonna replace my worn out tires with a set of 3rd Gen wheels and tires. My truck is a 1997 12-valve, 4x4, auto with 3. 54 gears and I'm wondering how the tires will effect power and mileage. Do you think I'll need a gear change? According to an online calculator, the 265/75-16s have a rev. per mile of 579 and the 3rd Gen tires are about 396. How will this effect the truck? Is the rear wheel ABS gonna get screwed up? Speedo gear change to correct the speedo reading?