Airride suspension is a form of air-assisted suspension for motor homes and smaller commercial vehicles up to about 3.5 tonnes that improves stability, safety, ride comfort, versatility and service life.
The airide suspension utilizes air springs or air “bellows” to provide extra support between the chassis and the axle of the vehicle. This type of suspension offers many benefits and it is relatively easy to install and requires only minimal adjustments to the existing suspension system.
Purpose of vehicle suspension
All suspension systems function to keep the vehicle’s wheels on the road surface as much as possible and to reduce the wear and tear caused by bumpy driving on driver, passengers and vehicle. The suspension accomplishes this by providing a type of buffer to compensate for bumps and other anomalies on the road’s surface.
A good suspension system alleviates shocks to the vehicle caused by unevenness of the road’s surface by reducing pitch, rebound and vibration. On road curves, suspension reduces the amount of drifting and rolling, so that the vehicle maintains good handling and stability.
Differences between traditional and airride suspension
The conventional vehicle suspension system consists of metal, usually steel, parts, including shock absorbers (dampers), leaf springs and connectors. The setup acts to absorb or dampen the shocks and jolts that occur when driving on an uneven road surface.
The system allows the wheels to “drop” into holes, dents and depressions on the road’s surface and it acts as a cushion when the vehicle hits bumps or other raised surfaces on the road.
The quantity of motion absorption of the spring is known as the spring rate and it is this rate that determines the overall ride quality. A soft or compliant spring rate affords a comfortable ride for the driver.
The dampers absorb spring energy so that they can resume their original shape quickly. Without dampers, the springs would “bounce” around until their energy dissipates and they resume their normal shape.
An airide suspension differs from this conventional arrangement in that it uses inflated rubber cylinders known as airride springs or airride bellows to assist the normal leaf springs and dampers.
Airride suspension complements and does not replace the conventional system using springs and dampers. The airide arrangement consists of air springs fitted between two solid metal or plastic plates at each end. An alternative form uses a rigid metal or plastic plate on top with a rigid metal or plastic “piston” on the bottom end.
In either case, the airide springs fit between the axle and the chassis usually in the place of the bump stops. These latter parts are rubber buffers that prevent contact between metal surfaces that can occur, for example, when the vehicle hits deep holes.
Installing the airride suspension requires very little modification to the conventional setup other than removing the bump stops and replacing them with the airride bellows.
Benefits of airide suspension
Air-assisted suspension for motor homes and light commercial vehicles helps reduce the wear on the conventional suspension system while providing a safer and more comfortable ride for driver and passengers.
Among the advantages of the airide system are improved straight-line stability, ride comfort, vehicle levelling, body roll stability and durability.
The airide system also offers the benefit of allowing drivers to raise the back of the vehicle temporarily to prevent damage from speed bumps or similar steep surfaces. In order to utilize this option, the vehicle must have an air compressor connected to the airride bellows.
• Straight-line stability – The air springs improve the stability of the vehicle when driving in a straight line to include providing buffering from strong side winds.
• Ride comfort – The air-filled springs act similar to secondary shock absorbers reducing the vibration, noise and jolts experienced in the cabin from road unevenness. The extra suspension provided by the air bellows can really make a difference when vehicles are heavily loaded resulting in compression of the conventional system.
• Vehicle levelling – Drivers can adjust lengthwise and side levelling by changing the air pressure in the airide springs. For example, if the vehicle leans too much to the right, the driver can either increase the pressure in right side air springs or decrease the pressure in the left side air springs. By keeping the vehicle level, you can reduce tire wear, increase stability and optimise headlamp illumination.
• Body roll stability – Air bellows provide additional suspension that reduces body roll when negotiating turns, bends and corners. The inertia of the vehicle causes it to lean to one side when handling curves in the road, a condition known as body roll. In some cases, the car may also slide or drift to one side. In extreme instances, the driver may lose control of the car if negotiating curves at excessive speed. Airride suspension reduces body roll by providing increased support.
• Durability – The air spring system provides increased shock absorption reducing the fatigue stresses on the leaf springs. The wear and tear on the springs can reduce their tensile strength causing sagging. Not only does airride suspension help prevent sagging, but it can compensate for loose springs when you adjust air pressure in the air bellows. For full vehicles with compressed springs, increasing pressure in the air springs will provide an extra degree of dampening.
Airride suspension is a simple way of improving conventional systems for motor homes and lighter commercial vehicles up to about 3.5 tonnes. The air springs are easy to install usually only requiring that you replace the bump stops with the new air bellow arrangement.
The air springs work with the conventional suspension system to provide greater dampening and a higher degree of versatility due to the capability of adjusting air pressure in the bellows. Benefits include a more comfortable ride, improved stability and reduced wear and tear.
By adjusting suspension air pressure, you can level the vehicle and compensate for sagging due to spring fatigue or a heavily laden vehicle. You can also raise the rear of the vehicle to prevent damage due to “bottoming-out” that can occur when driving over speed bumps or when boarding or leaving a ferry.
The air assisted suspension system is a cost effective method of improving safety, comfort, stability and service life of a motor home.
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