S.C. Code Ann. § 12-37-2645

For purposes of determining the appropriate assessment ratio used in the calculation of the assessed value of a motor vehicle and for defining those motor vehicles subject to the assessment ratios provided in Section 1(8)(B)(a) of Article X of the Constitution of this State, the definition of "private passenger motor vehicle" provided in Section 56-3-630 applies except that in the case of pickup trucks, the empty weight and gross weight limits provided in that definition are increased respectively to nine thousand pounds or less and eleven thousand pounds or less and the definition is deemed to include motorcycles.