13" Aluminum Twisted Spoke Trailer Wheel. The exact size is 13" x 5" 5 lug on 4.5" bolt pattern. Center hole diameter is 3.25 inches. Max load is 1660 Lbs per wheel. This listing is for the wheel only. Most common tire sizes mounted on this wheel are 165/80R13, 165/80D13 (A78-13), 175/80D13 (B78-13) and 175/80R13. If ordering center caps the size you would need is 3.25 inches.