Why do truck wheels sometimes hang in the air?

Have you noticed dangling wheels on some trucks? This seems strange to those who do not know anything about the design of heavy trucks. Maybe this indicates a breakdown of the car? Let's see why we need additional wheels.

Why don't the wheels touch the ground?

There is a misconception that the wheels of a truck that hang in the air are "reserves". For example, if one of the wheels is flat, the driver will very easily replace it. And since the wheels of heavy trucks are very massive, there is nowhere else to remove them. But this theory is wrong. Such wheels in the air are called "lazy bridge". This is an additional wheel axle, which, depending on the situation, rises or falls. You can control it directly from the driver's cab, there is a special button. It regulates the unloading mechanism, transferring it to various positions. There are three of them.

Transport

In this position, the "lazy bridge" hangs in the air. He clings to the body. All load on other axles.

Working

Wheels on the ground. part of the load on them. The car becomes more stable and brakes better.

Transitional

"Sloth" touches the ground, but does not perceive the load. This mode is used for driving on slippery roads.

Why you need a lazy bridge

Under certain circumstances, a “lazy bridge” can be very useful to the driver.

If a trucker has delivered a load and is driving with an empty body, then he does not need another wheel axle. Then they rise automatically. This significantly reduces fuel consumption. The driver spends less on several liters of gasoline per 100 kilometers. Another important factor is that tires do not wear out. The period of their work is increasing. It is important that with the additional axle raised, the machine becomes more manageable. She can maneuver and drive into sharp turns if she moves in the city.

When the heavyweight has fully loaded the body, he needs an additional wheel axle. Then the "lazy bridge" is lowered and the load is distributed evenly.

If it is winter outside, then an additional axle will increase the area of ​​adhesion of the wheels to the road.

What cars use "sloth"

This design is used on many heavy trucks. Among them are various brands: Ford, Renault and many others. European manufacturers put such a system on cars with a gross weight of up to 24 tons. As a rule, Japanese-made trucks with a total weight of up to 12 tons are used on Russian roads; they do not have axle overload. But for those where the total mass reaches 18 tons, such a problem arises. This threatens with technical difficulties and fines for exceeding axial loads. Here, drivers are saved by the additional installation of a “lazy bridge”.

If the truck's wheels are hanging in the air, it means that the driver has switched the "lazy bridge" into transport mode. "Lenivets" helps heavy trucks withstand heavy weight and correctly distribute it along the axles.