285/70 R17, which is the stock size for the Tundra Rock Warrior package. Slightly larger diameter than the stock 18" tire, and they rub very slightly at full lock on the inside of the mud flaps. Just a slight thump, thump, thump when backing up. I could shave the raised edge off the mud flaps, but there's really no need. The speedo is off by 1-2 mph at 70 mph according to my Escort radar detector, which has a speed readout--not enough to worry about. This Rock Warrior tire/wheel package is highly sought after by LC200 owners who do some off-roading, but there aren't many available. I found mine on Craig's List. It took two years because I live in the middle of nowhere.