How does an overrun brake work?

How does an overrun brake work? – main image

Contrary to appearances - the operation of the caravan does not boil down only to using the charms and comforts provided by its residential part. Spacious interior made of high-quality materials - durable floor coverings, solid furniture and rich furnishings. But that's not all. Issues related to the safety of its use, especially towing it to a place of vacation, are not much less important.

Driving with a caravan requires a lot more concentration, anticipation and fluency of movements from the driver than driving the car alone. The driver must take into account many factors that determine the safety of himself and other road users. The curb weight has a huge impact on the behavior of the towed trailer . The heavier our trailer is, the more we load the engine and the entire power transmission unit of the car. During deceleration, the braking system works with double force. Fortunately, only very light constructions are devoid of their own braking system - the other (heavier) trailers are equipped with an overrun brake .

How it's working?

This legally required element of equipment for heavier caravans (not only camping ones) uses its own weight and inertia to function. During braking, the speeding trailer pushes the drawbar against the car hook - at this moment the overrun brake is activated. Depending on the applied solution ( tie rods, hydraulics or levers ), a piston rod placed in the drawbar or a set of levers starts the braking procedure - the friction jaws touch the drum surface or the blocks rub against the discs . However, we must remember about the delay with which the overrun brake works in relation to the braking vehicle.

On many older trailers equipped with an overrun brake, you must block it before reversing - otherwise the brakes will jam in the blink of an eye. Newer models of trailers are equipped with an automatic reversing mechanism , thanks to which we avoid constantly leaving the car before reversing. Regular service of the entire mechanism is equally important. A winter break of several months is an excellent time for the development of corrosion , which can easily prevent the entire system from working properly .

Overrun brake in practice

Towing a trailer with an overrun brake requires from the driver, first of all, smooth driving . Avoiding sudden maneuvers or sudden braking , we will use the technical properties of the trailer braking system to the maximum extent - without unnecessary overloads that could cause uncontrolled skid of the entire set . Smoothly and steadily increasing the pressure on the brake pedal, we will gain time to start the trailer braking system.

Overrun brake increases safety when traveling with a towed trailer. Thanks to it, the considerable curb weight of the trailer and its inertia make it less difficult to operate the vehicle on the road.

Maciej Mokwiński
Maciej Mokwiński

I follow the latest trends in the automotive industry, not only in caravanning

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