A standard monster truck tire has a diameter of 66 inches.
Competition monster trucks typically use enormous terra tires measuring about 66 inches in diameter and 43 inches wide. They are adapted from tires used on agricultural equipment and are mounted on rims about 25 inches in diameter. Their size gives monster trucks the ground clearance and flotation needed for rough terrain, ramps, and vehicle-crushing displays.
The 66-inch figure became especially associated with the early growth of modern monster trucks. In the late 1970s, heavily modified trucks often ran tires around 48 inches in diameter. Bob Chandler’s Bigfoot debuted 66-inch tires at a 1982 event, and other prominent trucks soon adopted the larger size.
“Standard” describes the common competition specification, not an unchanging rule for every monster truck. Special exhibition vehicles and custom builds can use different tire dimensions. The tire’s diameter is also distinct from its width and rim diameter, which are much smaller measurements.
A typical competition monster truck is roughly 12 feet tall and weighs several tons. The huge tires are only one part of the package; specialized suspension, steering, axles, and reinforced chassis are equally important.