Chassis

A monster truck chassis (or also known as a rollcage) is the basic construction of a monster truck. It is essentially a truck in itself without the fiberglass body.

History
Monster truck chassis are what compose the modern monster truck, following the days of using regular truck frames on larger tires. Using a chassis for a monster truck became famous in the late 1980's and continued into the 1990's. Today, nearly all competing monster trucks are composed of a chassis (although some less known, non competing trucks are still built this way).

Differences
No two monster truck chassis are exactly the same. They may vary in terms of length, height, width, and in rare cases even weight. They may also vary in terms of wheel base length and suspension. Trucks may also have their chassis painted to match their theme and color scheme.

Uses
Motorsports leagues like FELD may have spare chassis for use in the case of a truck's regular chassis breaking, or they may also use the chassis of another truck. This happened in 2015 when Backwards Bob was destroyed in a trailer fire. It returned soon after on a spare PEI chassis. A year before, in 2014, Titan crashed hard into the wall during qualifying of Monster Jam World Finals 15, so Titan ran the actual World Finals on the Mohawk Warrior chassis instead.

Some chassis actually have multiple identities. Examples of this include Devastator and The Felon, both of which are run on the same chassis. Driver Mark Schroeder alternates between the two every season. Another example is Wrongway Rick, a truck that runs on and off on the Obsession chassis.