What Type of Brakes Does a Semi-Truck Have?

Semi-trucks are the largest vehicles on the road. They have immense power and can haul thousands of pounds of cargo over long distances.

As such, they require powerful brakes to bring them to a stop in an emergency situation. Semi-trucks have a variety of braking systems, depending on the manufacturer, but most share some common elements.

Air Brakes

The most common type of brakes used on semi-trucks are air brakes. Air brakes use compressed air to create friction on the brake pads, which slows down the truck’s wheels.

The air pressure is generated by an engine-driven compressor and stored in an onboard tank. When the driver applies pressure to the brake pedal, a valve opens and releases compressed air that activates the brakes.

Drum Brakes

Drum brakes are found on many semi-trucks as well. Like air brakes, drum brakes use friction to slow down the vehicle’s wheels.

The friction is generated by brake shoes that press against the inside of a metal drum attached to the wheel hub. Drum brakes are less effective than air brakes but are much more reliable and require less maintenance.

ABS Brakes

Another type of brake used on semi-trucks is anti-lock braking system (ABS) brakes. ABS brakes use hydraulic pressure to activate specialized valves that prevent wheel lockup during hard braking maneuvers. This helps maintain steering control and prevents skidding or sliding in wet or icy conditions.


Semi-trucks have powerful braking systems designed for safety and reliability when transporting heavy loads over long distances. The most common types of brakes used on semi-trucks are air brakes, drum brakes, and ABS (anti-lock braking system) brakes.

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Stephen Dunn