You need the 18" or larger wheels due to caliper size. I also checked to see if I could run 16" wheels because the tires that came w/the truck are worthless and tires for 18" wheels are outrageus. Also, with the 18" wheel package, if your truck is a job #3 you have 3.55 gears 20" have the 3.73 gears a 4% diffrence. FYI