Inertia Vs. Electric Trailer Brakes

by Edmund Gary
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camping,trailer image by Greg Pickens from

Dangerous says most states have regulations governing trailers weighing more than 3,000 pounds. There is little if any regulation for trailers weighing under 3,000 pounds. If a trailer is designed to carry 3,000 pounds, it must have a working braking system. Two types of braking systems are available: inertia trailer brakes and the electric trailer brakes.

Brake Controllers

Electric brake controllers are automobile original equipment manufactured or aftermarket-installed device modules. They activate the trailer brakes and are needed if the trailer uses electric brakes. The controllers are mounted on or underneath the tow vehicle's instrument panel on the driver's side. The controllers can come in different product classes, such as proportional or inertia brake controllers.

Electric Trailer Brakes

Electric brakes feed power from the tow vehicle's brake lights into the controller. The trailer brakes are activated by a separate heavy-duty circuit through a plug and socket. This allows the brakes to work automatically whenever the tow vehicle's brakes are applied. Properly adjusted controllers can allow tow vehicle and trailer combination to come to a stop as smoothly as if the tow vehicle was by itself.

Inertia Trailer Brakes

Inertia activated brakes offers smooth stopping response in most situations. According to RV technician Reg DeYoung, the inertia brakes has an internal sensing device or a pendulum which senses the tow vehicles rate of deceleration. The sensing device then applies the amperage to the trailer brakes at the same rate of deceleration as the tow vehicle.

Drawbacks of Inertia and Electric Brakes

The pendulum of the inertia brakes may not swing correctly because of changes in the angle or changes, and this can lead to jerky stops, according to Hensley Manufacturing.

Electric brakes tend heat up to a temperature of 300 degrees Fahrenheit. This changes the resistance in the magnets in the brake system, which leads to brake fade.


Trailer brakes are a crucial piece of equipment when the trailer has reached a specific weight threshold. Some states in the United States may have very little regulation of trailer brakes for units under 3,000 pounds, but it is best to check the local regulations where the trailer will be operated.

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