Image Item No. Description  18976c01 (Inv)  Wheel 18mm D. x 12mm with Axle Hole and Stud with Black Tire 24 x 12 Low (18976 / 18977) Catalog: Parts: Wheel & Tire Assembly  56145c05 (Inv)  Wheel 30.4mm D. x 20mm with No Pin Holes and Reinforced Rim with Black Tire 49.5 x 20 (56145 / 15413) Catalog: Parts: Wheel & Tire Assembly