Modern monster truck bodies are typically made from fiberglass. The lightweight panels are attached separately to the truck’s tubular chassis, rather than forming part of the vehicle’s main structural frame.
Fiberglass is useful because it is much lighter and easier to repair or replace than steel bodywork. A team can remove damaged panels after a crash and fit new ones without rebuilding the suspension, frame, or drivetrain. It also allows designers to create dramatic shapes and recognizable themes such as Grave Digger, Max-D, or Megalodon.
The body is mostly cosmetic: the chassis, suspension, axles, engine, and safety structure do the hard work. Early monster trucks were heavily modified pickup trucks with more conventional stock bodies, but modern competition trucks are purpose-built machines that only resemble pickups or SUVs on the outside.
Fiberglass is sometimes confused with plastic or carbon fiber. Fiberglass is a glass-fiber-reinforced composite, usually formed with resin. It provides a practical balance of low weight, flexibility, cost, and replaceability for a vehicle designed to survive spectacular impacts.