All of them are composed of some steel construction, but not 100 percent constructed of steel. Much of it varies with each product for the amount of metal construction is used. Invariably, all of them have rubber tires and/or a plastic fender. It can be a mix-and-match build. Typically, the cab and chassis of a particular vehicle is metal.
As in the case of the dump truck, the flatbed is metal. With the crane, typically the cab is metal. One crane listed has an entirely metal constructed arm and bucket.