Actual tractor trucks are often seen with plain natural-metal wheels made of steel or aluminum. To depict this type of wheel, these matte finish metal-plated wheels for 1/14 scale R/C tractor trucks and semi-trailers are available as an option accessory. By simply replacing with kit-standard gloss finish metal-plated wheels, you can give your truck or trailer a different appearance. Specs and Features These wheels are designed for use with tires of 30mm width.Item 56519 uses Hex Hubs and Item 56520 uses 1150 ball/metal bearings to attach to the axle.Each item includes 1 pair of wheels.For Item 56319 3-Axle Reefer Semi-Trailer, you will need 2 sets of Item 56519 and 1 set of Item 56520.For Item 56326 40-Foot Container Semi-Trailer, you will need 3 sets of Item 56519.