S.C. Code Ann. § 56-3-630: Vehicles classified as passenger motor vehicles.

The Department of Motor Vehicles shall classify as a private passenger motor vehicle every motor vehicle which is designed, used, and maintained for the transportation of ten or fewer persons and trucks having an empty weight of nine thousand pounds or less and a gross weight of eleven thousand pounds or less, except a motorcycle, motorcycle three-wheel vehicle, or moped. The department shall classify a three-wheel vehicle by the manufacturer's certificate of origin for the vehicles initial registration. For subsequent registration, the department shall classify the three-wheel vehicle by its title document. This section does not relieve or negate any applicable fees required under Section 56-3-660.