How do air helper spring kits aid suspension?
Arnott explains the compromise LCV vehicle manufacturers need to make concerning suspension and why an air helper spring kit can provide the perfect solution.
Light commercial vehicles are designed for a wide variety of uses but are mainly used for transporting people, cargo, or a combination of both. This means that LCV manufacturers need to offer multiple configuration options so all customers can tailor the vehicle to their specific needs giving rise to different configurations including people carriers, vans, chassis cabs. Additionally, the different chassis options are selectable with different interior configurations, in multiple lengths, heights and maximum permissible weights.
The LCV suspension system needs to provide a safe, durable, and heavy-duty construction to cope with the occupants and/or goods that are transported, all while providing the highest possible level of ride comfort. The challenge here lies in the extensive configuration choices, meaning that the vehicle’s suspension needs to be constructed to manage a wide range of load conditions.
Almost all manufacturers use either a conventional coil set-up or a leaf spring configuration in their suspension systems. The advantage of using coil springs is that it provides more overall comfort, whereas a leaf sprung suspension, due to its progressive nature, can handle heavier loads.
Compromise
The compromise LCV manufacturers need to make is inevitable because the suspension solution needs to be suitable for both an empty as well as a fully loaded vehicle. Therefore, suspension solutions are developed for average loads, providing the maximum possible comfort when empty and at the same time providing necessary safety and stability for a fully loaded vehicle. Consequently, the suspension can be too strong, making the ride harsh and uncomfortable for an unloaded vehicle. On the other hand, the suspension is too weak for permanently loaded vehicles, overstressing the suspension in the long-term, causing premature wear of the suspension and an uncomfortable driving experience.
Driving on the limit
Given that a chassis and suspension are designed for an average load, the higher the load capacity the bigger the “challenge” for the original suspension’s ride and handling capabilities. Even if a buyer knows he will often or always exceed this average load, they still need to rely on the “standard range of suspension” offered by the vehicle manufacturer and select the correct base vehicle as a start.
The solution
What the vehicle needs if the average load is (almost) always exceeded is an increase in load meaning additional permissible total weight to generate more payload. A reinforced conventional spring could be a cost-efficient solution, but it remains a compromise since it has a fixed value of strength. Consequently, this set-up will hardly ever be ideal, making the suspension still too or not harsh enough depending on load conditions.
Air helpers offer an adjustable solution to manage cases of more permissible gross weight or an increase in the maximum permissible axle load. First, the spring reinforcement optimises the suspension, increasing the safety and usability of the vehicle. Air helper springs are the most convenient and flexible solution because no matter if the vehicle is empty, permanently partly loaded or always fully loaded, it always has the capacity of providing the best possible drive comfort and maximum safety and stability! Second, since the suspension is not overstressed, air helper springs eliminate premature wear and tear and improve drivability, increasing the vehicle’s lifespan. Other advantages are the adjustability for uneven load and manual leveling when parked.
Increased load
Arnott air helper springs are designed and engineered to complement the suspension, preventing it from sagging with increased payload and providing extra stability and increased ride comfort. For example, our latest release is an air helper spring kit for the 2006-current Fiat Ducato/Citroen Jumper/Peugeot Boxer (AH-4471), that makes it possible to achieve a gross weight of 4090kg while rear axle load can be increased to 2240kg for the 15in (stock wheel size) light chassis.
