What Is A Bobtail, And How Is It Different From A Semi Truck?

A bobtail is a trucking parlance for a truck without a trailer. Meanwhile, truckers refer to semi-trailers (or semis) as trucks with one or multiple trailers to haul cargo. It means the difference between a bobtail and a semi is the absence of a trailer. It's commonly termed a "cargo-free" truck.

The term "bobtailing" differs slightly from what truckers call "deadheading." Bobtailing is driving a freight truck without a trailer. On the other hand, deadheading means driving a truck with a trailer but without any cargo. Bobtail can also refer to small propane trucks with custom-fitted tanks on the rear bed, resembling a breed of short-hailed cats or bobcats.

Bobtailing, or driving a semi without a trailer, might seem fun, bringing to mind the track antics of semi-truck racing. But in reality, bobtailing generates zero revenue for truckers, and driving a semi without a trailer affects the truck's ride, handling, and stability.

Driving a semi without a trailer means the front wheels are more load-bearing and could make the truck more challenging to steer. Moreover, a bobtail truck can accelerate faster than a loaded semi, exacerbating the steering issue at higher speeds. With less weight on the rear wheels, a bobtail truck has less frictional force, which can make the truck skid when tackling corners or sharp curves.

In addition, braking is more challenging in a bobtail truck. The rear wheels provide most of the braking power in a semi. Without any load in the rear, braking power is weaker than with a loaded trailer, and pressing hard on the brake pedal (such as in an emergency) could make the rear wheels seize and affect the truck's stability under braking.

With all the inherent risks, driving a bobtail truck on icy, snowy, or wet roads is incredibly challenging, not to mention coping with a bumpy ride due to the absence of any load-bearing weight in the rear. Truckers could drive a bobtail after unloading or when picking up a trailer, but the preferred choice is to hit the road with a loaded trailer to make the truck more stable and earn healthy profits.