My 2004 Silverado 1500 2wd had 16" rims, but a previous owner put 17" (GM 4x4 rims) wheels on it. The tires are 265-7017 and my speedometer is off by 2 or 3 mph, depending on speed. If it reads 72, I am traveling 75 mph.
Aside from looking like a 4x4 from a distance, the truck rides normally. It has Goodyear rubber, but I'll probably replace them with Michelins in December when my state inspection is due. My current tires have a bit of tread remaining, but I don't want to take chances with my truck only being rear-drive. (It's like a duck on ice when I try to drive it in snow.)
P.S. To check your speedometer accuracy, I know of three ways to do it. First, get a cop to measure your speed with radar. Second, use a mile marker and time the number of seconds it takes to get from one to the other at 60 mph, which should be 60 seconds if you cover exactly one mile. Third, use a GPS while driving a fair distance at a set speed. The GPS readout should match your truck's speedometer.