How Towing Braking Systems Work

By: John Fuller

If you plan on towing a street vehicle along with your RV, a towing braking system is necessary. See more truck pictures.
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Recreational vehicles (RVs) are great investments for those who like to see as much of the country as possible without having to spend too much on hotels -- once you're ready to turn in for the night, you can simply pull over to a campground and settle in. The next morning, you wake up, make breakfast, jump in the driver's seat and head off down the road.


Although the RV will be your main mode of transportation and shelter, it won't always be the only vehicle you'll drive on a trip. If you want to spend time in certain points during a trip and explore more of a new city or town, it's necessary to tow your street vehicle along with you. An RV is meant for the long haul and wide-open highways, and since it's too big and clumsy to driver around narrower streets, a more traditional car, truck or SUV might help you make the most of your visits.

If this is the case, though, the additional weight of a towed vehicle will make braking a sensitive issue. If you're thinking about towing another vehicle with your RV, a towing braking system is the first step. What do braking systems do for towing vehicles, and why are they so important?


Types of Towing Braking Systems

Depending on the type of RV you own, it helps to know the different kinds of towing braking systems in order to choose the best one. Above is a surge braking system.
Depending on the type of RV you own, it helps to know the different kinds of towing braking systems in order to choose the best one. Above is a surge braking system.

Why do RVs need braking systems when they're towing? Think of the two vehicles, the tower and the towed, as two runners running in single file. If both run at about the same speed, slowing down and speeding up at the same time, the athletes should be able to jog around without much trouble. If the runner in front stops abruptly without notifying the runner behind him, chances are the latter will bump into him, slowing down the progress of the jog and perhaps injuring one or both of them.

In the same way, an RV's brakes need to communicate with the towed vehicle's brakes. Without a proper braking system, the weight and momentum of the towed vehicle will put extra strain on the RV's brakes, wearing out the system and creating a potentially dangerous situation.


There are essentially three types of towing braking systems:

  • In a surge braking system, a slide receiver is used as the tow bar. When your RV slows down, the slide receiver pushes in and mechanically operates a lever, which is hooked up to the towed vehicle's brakes.
  • Deceleration systems detect the changing momentum of your RV. Mercury switches, pendulums or accelerometers detect how fast or slow your vehicle is traveling, and then passes the braking information along to the towed vehicle's brake via wires.
  • Pressure systems use electronics to detect how hard you push on your RV's brake pedal and send the appropriate amount of power via wires to the towed vehicle's brakes.

There are also two different ways these systems can work. Braking systems are either proportional or time delayed. A braking system that is proportional gives the same amount of brake pressure to both the RV's brakes and the towed vehicle's brakes. If you tap lightly on your RV's brakes, for instance, the amount of power directed toward the towed vehicle's brakes will be equivalent. Time-delayed braking systems, on the other hand, let you set a certain amount of power to send to your tow vehicle after a pre-determined amount of time.


Installing Towing Braking Systems

Installing can be simple or complicated depending on the type and how often you switch motor homes. Above is a portable braking system.
Installing can be simple or complicated depending on the type and how often you switch motor homes. Above is a portable braking system.

The relative difficulty of installing a towing braking system into an RV greatly depends on how frequently you change motor homes. Some people may shop around for different RVs, buying and selling for the right kind, while others are content with their choice and intend to use their RV for many years to come.

A portable braking system is recommended for drivers who change RVs frequently or switch between different towed vehicles. Installation for these systems usually takes about one hour and typically involves adjusting a pedal clamp over your RV's brake pedal, plugging in the wiring harness and the inserting the power cord into a power source.


A direct braking system, on the other hand, is meant for people who typically tow one vehicle behind their RV. It's connected directly to your RV's braking system, so installation takes much longer and is more demanding. Having a direct braking system doesn't make the setup permanent; it simply is easier to move a portable braking system from one towing vehicle to another.

Towing braking systems often come with breakaway kits, battery-powered electronics that detect when a towed vehicle has separated from its hitch. The battery immediately sends power to the unhitched vehicle's brakes, slowing the runaway trailer or car down and stopping any potential damage to other drivers.

For lots more information on towing braking systems and other protective towing equipment, slow down for the links on the next page.


Lots More Information

Related HowStuffWorks Articles

More Great Links


  • Automotive Accessories Connection. "How to install an electric trailer brake control on a tow vehicle." (Oct. 11, 2008)
  • Roadmaster. "Which system is right for me -- BrakeMaster, Even Brake, or the 9700?" 2007. (Oct. 11, 2008)
  • "Supplemental brake systems."Aug. 7, 2006. (Oct. 11, 2008)
  • Truck Parts Specialists. "Why a tow brake, and which one to choose?" 2005. (Oct. 11, 2008)