Yesterday I replaced 275/55/20 (stock size) ko2s with 285/55/20 ko2s on my 17 Tundra. Along with this I got an oil change, multi point inspection, f&r diff,and transfer case fluid changes. I got an alignment 4000 miles ago and did not get one with the new tires. The truck was not pulling and still feels like it drives perfectly straight.

The truck seems to take significantly more gas to accelerate and cruise. I can audibly hear the engine load is higher when cruising at 40 mph. When coasting the truck seems to slow down faster than usual, and overall I got about 1.5 mpg less gas milage on my way to work.

Is it normal for 10mm wider tires to make that big of a difference? Did I make a mistake not getting the alignment with the new tires?