Encyclopedia of Slide-in Campers: Knowledge About Suspensions on Slide-in Campers

Tags: Slide-in Camper, Camper Suspension, Camper Knowledge, Suspension Classification

Slide-in campers are usually used for medium and long-term trips, so passenger comfort is crucial. Driving comfort largely depends on the suspension system, which is undoubtedly a major challenge for slide-in campers mainly based on commercial vehicle chassis. Currently, the suspension systems used in slide-in campers are mainly classified into the following types according to different elastic elements adopted.

Leaf Spring Suspension

A leaf spring is the most widely used elastic element in automobile suspensions. It is composed of a number of alloy spring leaves of unequal lengths stacked together to form a beam of approximately equal strength. This leaf spring suspension, usually equipped on commercial vehicles for heavy loads, is often referred to as a leaf spring suspension, and it must be modified to be suitable for slide-in campers.

Advantages:Simple structure, low manufacturing cost, wide application, high reliability due to high strength, and the ability to lower the height of the vehicle body floor. When used in vehicles with large changes in body weight, it can keep the wheel angle from changing easily when the body height is lowered, maintaining consistent handling feel and unchanged riding comfort.

Disadvantages:Poor vibration resistance. Therefore, when a slide-in camper travels on rough roads, it will vibrate violently. Passengers will feel very uncomfortable when the slide-in camper goes through various sharp turns. Slide-in campers with a higher center of gravity are more likely to cause passengers to lean. Reducing load does not bring substantial help, and storing items in overhead cabinets and roof boxes will worsen the problem. Crosswinds and high-speed driving also easily cause the vehicle body to tilt.

Coil Spring Suspension

A coil spring is a spiral made of spring steel by coiling, including cylindrical coil springs with constant stiffness and conical coil springs with variable stiffness. Coil springs are mostly used in independent suspensions, especially front-wheel independent suspensions, but some rear non-independent suspensions also use coil springs as elastic elements.

Compared with leaf springs, coil springs have the characteristics of no friction, small longitudinal space occupation and light self-weight, so they are also widely used. Like leaf springs, coil springs have the advantages of low cost, reliability and wide application, but they also have the same disadvantage of causing more bumps during driving. Moreover, since coil springs can only bear vertical loads, suspensions using them as elastic elements must be equipped with guiding devices. Meanwhile, coil springs do not generate friction when deformed, so shock absorbers must be installed to attenuate vibrations caused by impacts.

Torsion Bar Suspension

A torsion bar spring is a rod made of spring steel with torsional rigidity. One end of the torsion bar is fixed on the frame, and the other end is connected to the wheel through a swing arm. When the wheel bounces, the swing arm swings around the axis of the torsion bar, causing the torsion bar to produce torsional elastic deformation, thus acting as an elastic connection between the wheel and the frame.

Suspensions using torsion bar springs as elastic elements need to be equipped with guiding devices and shock absorbers. Compared with leaf springs, torsion bar springs are lighter in weight, require no lubrication, are easy to maintain, have variable stiffness and convenient body height adjustment, and can save longitudinal space.

The advantage of using torsion bar springs is that they lower the center of gravity of slide-in campers, helping to prevent rollovers. However, they have a shorter service life, higher failure rate, and higher replacement and maintenance costs.

Air Suspension

A gas spring uses air as the elastic medium, that is, compressed air is filled in a closed container, and the spring effect is realized by the compressibility of air. Since gas springs can only bear vertical loads, suspensions using them as elastic elements must also be equipped with guiding devices and shock absorbers.

Advantages:Gas springs can dynamically adjust the height of the vehicle suspension and chassis. The on-board compressor generates air, and the system is equipped with an air tank that deflates and expands according to the pressure handled by the suspension system, without fatigue like other steel springs, rear-end collapse or loss of elasticity under long-term load. Air suspension is usually the smoothest among all suspension types.

Disadvantages:Air spring suspension is the most expensive and the most troublesome to maintain.

To meet the ride comfort requirements of high-end slide-in campers, air suspension can be installed with a computer feedback system that maintains and controls the body height. The load capacity affects the pressure in the air tank, and the monitoring system automatically adjusts the deflation and inflation cycles. Therefore, the body height remains constant no matter how much weight the user adds or removes.

Air Assist

The descriptive term "air assist" refers to a "combined system" that enhances the performance of leaf spring and torsion bar suspensions through auxiliary air tanks. Despite misleading statements in some advertisements, it cannot be called "air suspension". As mentioned above, it is merely an auxiliary device that relies on the "cushioning" effect of air.

Undoubtedly, such an air assist configuration is very useful when steel springs become fatigued and the rear end collapses significantly. The handling stability of slide-in campers will be greatly improved. Air assist units can be retrofitted, and these air assist components need to be modified to match the brake settings. This is very important to know if you want to retrofit your existing slide-in camper accordingly.