Chassis solutions by spring system
Chassis Solutions by Spring System
Most vehicles come standard with leaf springs or coil springs. The appropriate chassis solution depends on the existing spring system, axle loads, intended use, and load position.
Depending on the vehicle, chassis solutions can also form the basis for an up-rating. Whether and to what extent an up-rating is possible depends on the specific vehicle, technical requirements, and available expert opinions.
On this page, you will find an overview of the most important chassis solutions for leaf springs and coil springs, as well as their typical applications.
Important: Consider Overhang and Load Distribution
The load on an axle is determined not only by weight but also by the position of the load.
If the payload is located behind the rear axle, a lever effect is created. This can significantly increase the load on the rear axle more than the actual weight of the load would suggest.
Typical examples:
- Pickups with truck campers
- Motorhomes with rear garages
- Motorcycle carriers
- Bicycle carriers
- Box bodies
- Service bodies
- Expedition vehicles
The greater the overhang behind the axle, the stronger the lever effect on the chassis and axle loads.
When selecting a chassis solution, the following should always be considered:
- Vehicle weight
- Axle loads
- Load distribution
- Overhang
- Intended use
Chassis Solutions for Winter Service Vehicles
Winter service vehicles place special demands on the chassis. Often, both the front and rear axles are additionally loaded.
Typical loads:
- Snow plow on the front axle
- Spreader on the rear axle
- Additional hydraulic and mounting systems
- Salt or brine tanks
A snow plow can generally be used on almost all winter service vehicles. This creates an additional load on the front axle, which must be considered when selecting the chassis solution.
For vehicles with spreaders, there is also a high load on the rear axle.
Winter service vehicles are often reinforced on both the front axle (snow plow) and the rear axle (spreader).
Leaf Spring Systems
Helper Springs for Leaf Springs
Additional coil springs support the existing leaf spring and increase the vehicle's load capacity. Depending on the vehicle, axle load, and available installation space, different spring sizes and arrangements are used.
For some vehicles, one helper spring is installed per side, while for others, two helper springs are used per side.
Advantages
- Supports the standard leaf spring
- Increases load capacity
- Suspension travel is maintained
- High driving comfort even when loaded
- More comfort than additional leaf springs
- Maintenance-free
- No air supply required
- Ideal for permanent loads
Suitable Vehicles
- Pickups with leaf spring rear axle
- Vans with leaf spring rear axle
- Trucks with leaf spring rear axle
- Trucks with leaf spring front axle
Available Axles
- Rear axle
- Front axle (selected trucks)
Typical Applications
- Truck campers
- Box bodies
- Service vehicles
- Workshop vehicles
- Travel vehicles
- Trailer operation
- Municipal vehicles
- Expedition vehicles
- Winter service vehicles
Available Versions
Depending on the vehicle and axle load, helper springs are available in different spring rates. This allows the chassis solution to be optimally adapted to the payload and intended use.
Note: Many vehicles with leaf spring rear axles have coil springs on the front axle. Therefore, different chassis solutions can be used for the front and rear axles.
Helper Air Springs for Leaf Springs
Helper air springs support the existing leaf spring and allow adaptation to different loading conditions. The air pressure can be adjusted depending on the payload and intended use.
For selected vehicles, reinforced systems are also available. These feature larger air bellows, reinforced brackets, and additional crossbars for better force distribution and higher stability under heavy loads.
Advantages
- Supports the standard leaf spring
- Air pressure individually adjustable
- Improved driving stability
- Compensation for load and trailer weight
- Vehicle level can be largely maintained even when loaded
- Reduces vehicle sag under load
- High driving comfort
- Less body roll and pitch
- Ideal for varying loads
Suitable Vehicles
- Pickups with leaf spring rear axle
- Vans with leaf spring rear axle
- Trucks with leaf spring rear axle
- Trucks with leaf spring front axle
Available Axles
- Rear axle
- Front axle (only selected trucks)
Typical Applications
- Truck campers
- Box bodies
- Travel vehicles
- Service vehicles
- Municipal vehicles
- Trailer operation
- Vehicles with varying loads
- Vehicles with high permanent loads
- Winter service vehicles
Available Versions
Depending on the vehicle and axle load, different air bellows sizes and load capacity variants are available.
For selected vehicles, reinforced systems with larger air bellows, reinforced brackets, additional crossbars, higher lateral stability, and better force distribution are available.
Air Supply
- Manual inflation via tire inflation valves
- Inflation via an on-board compressor with control unit in the driver's cab
- Use of the vehicle's existing compressed air system (for many trucks)
On-board Compressor
An on-board compressor allows comfortable adjustment of air pressure directly from the driver's seat.
With many systems, the left and right sides of the vehicle can be controlled separately. This allows targeted compensation for uneven loads, one-sided loads, or different weight distributions.
For selected truck systems, air pressure regulation is also possible via radio remote control.
Coil Spring Systems
Reinforced Replacement Springs
Reinforced replacement springs replace the standard coil springs and increase the vehicle's load capacity.
Advantages
- Replaces the standard coil spring
- Higher load capacity
- Less sag when loaded
- Improved driving stability
- Maintenance-free
- No air supply required
- Permanent solution for heavy loads
Suitable Vehicles
- Passenger cars
- Station wagons
- SUVs
- Off-road vehicles
- Pickups with coil spring suspension
- Vans
- Motorhomes
Available Axles
- Front axle
- Rear axle
- Both axles
Typical Applications
- Motorhome conversions
- Workshop installations
- Winches
- Bull bars
- Roof tents
- Additional equipment
- Permanently high loads
- Winter service vehicles with snow plows and/or spreaders
Available Versions
Depending on the vehicle and axle load, reinforced replacement springs are available in different spring rates.
Helper Springs for Coil Springs
Helper springs are mounted inside the existing coil spring and support the standard spring under heavy loads.
Advantages
- Supports the standard coil spring
- Increases load capacity
- Suspension travel is largely maintained
- Good combination of comfort and load reserve
- Maintenance-free
- No air supply required
Suitable Vehicles
- Passenger cars
- Station wagons
- SUVs
- Off-road vehicles
- Pickups with coil spring suspension
- Vans
- Motorhomes
Available Axles
- Rear axle
- Front axle (vehicle-dependent)
Typical Applications
- Motorhome conversions
- Fixed interior installations
- Additional batteries
- Water tanks
- Tool and service vehicles
- Vehicles with high permanent loads
- Winter service vehicles
Available Versions
Depending on the vehicle and axle load, helper springs are available in different spring rates.
Helper Air Springs for Coil Springs
Helper air springs support the existing coil spring and allow adaptation to different loading conditions.
Depending on the vehicle, the air bellows are mounted either inside or next to the coil spring.
Advantages
- Supports the standard coil spring
- Air pressure individually adjustable
- Improved driving stability
- Compensation for load and trailer weight
- Vehicle level can be largely maintained even when loaded
- Reduces vehicle sag under load
- High driving comfort
- Less body roll and pitch
- Ideal for varying loads
Suitable Vehicles
- Passenger cars
- Station wagons
- SUVs
- Off-road vehicles
- Pickups with coil spring suspension
- Vans
- Motorhomes
Available Axles
- Rear axle
Helper air springs for coil springs are almost exclusively used on the rear axle. Helper air springs on the front axle are only available for selected truck systems and are structurally part of the leaf spring systems.
Typical Applications
- Caravan operation
- Trailer operation
- Rear carriers
- Motorcycle carriers
- Motorhome conversions
- Vehicles with varying loads
- Winter service vehicles
Available Versions
Depending on the vehicle and installation space, different air bellows sizes and load capacity variants are used.
Air Bellows Inside the Coil Spring
For most vehicles, the air bellows are mounted inside the existing coil spring.
Important: The minimum pressure prescribed by the manufacturer must always be maintained. This prevents the air bellows from being damaged by movements within the coil spring.
Air Bellows Next to the Coil Spring
For some vans and selected vehicles, the air bellows are mounted next to the coil spring.
This allows larger air bellows to be used and higher loads to be supported.
Air Supply
- Manual inflation via tire inflation valves
- Inflation via an on-board compressor with control unit in the driver's cab
On-board Compressor
With many systems, the left and right sides of the vehicle can be controlled separately.
This allows targeted compensation for uneven loads and one-sided loads.
Full Air Suspensions
With a full air suspension, the standard coil springs on the rear axle are completely replaced by air springs.
Full air suspensions are primarily designed for driving comfort and level control. For vehicles with permanently heavy loads or large rear overhangs, helper air springs are often the more suitable solution.
Advantages
- Completely replaces the standard coil springs on the rear axle
- Very high driving comfort
- Particularly smooth driving behavior
- Vehicle level can be kept largely constant regardless of load
- Compensation for uneven loads possible
- Less body roll and pitch
- Improved driving stability
- Comfortable level control
Suitable Vehicles
- Vans
- Motorhomes
- Passenger transport vehicles
- Emergency vehicles
- Off-road vehicles
- SUVs
- Pickups
Not Suitable For
- Trucks
Available Axles
- Rear axle
Typical Applications
- Increased comfort
- Passenger transport
- Emergency vehicles
- Ambulances
- Motorhomes
- Shuttle vehicles
- Travel vehicles
- VIP and special vehicles
- Vehicles with varying loads
Air Supply
Full air suspensions should always be operated with a permanently installed compressor.
The compressor handles:
- Pressure regulation
- Level control
- Automatic pressure equalization
With some systems, the vehicle can be lowered when stationary to facilitate loading and unloading or improve entry. This can be advantageous, for example, for motorhomes, wheelchair-accessible vehicles, or special vehicles.
When are Helper Air Springs the Better Solution?
Helper air springs are often the better choice when the focus is on high payload, large rear overhangs, or permanently high axle loads.
This applies in particular to:
- Heavy motorhomes
- Pickups with truck campers
- Vehicles with a large rear overhang
- Vehicles with a high rear axle load
- Vehicles with permanently high loads
Full air suspensions, on the other hand, are primarily interesting for drivers who value driving comfort, level control, and improved handling.
Which Chassis Solution Suits My Vehicle?
The appropriate chassis solution depends on the spring system of the respective axle and not exclusively on the vehicle type.
Many vehicles are available with different spring systems depending on the model, body type, wheelbase, or version.
Leaf Springs
- Helper springs
- Helper air springs
Coil Springs
- Reinforced replacement springs
- Helper springs
- Helper air springs
- Full air suspensions
Important
A vehicle can have different spring systems on the front and rear axles.
Examples:
- Coil springs front, leaf springs rear
- Coil springs front, coil springs rear
- Leaf springs front, leaf springs rear
- Air suspension on one axle and leaf or coil springs on the other axle
Even within the same model series, different suspension systems may be installed. Therefore, the selection of a chassis solution should always be based on the actually installed suspension system.
Not sure which suspension system your vehicle has?
The existing suspension system, axle loads, and intended use are crucial for selecting the right chassis solution.
We are happy to assist you in choosing the suitable chassis solution for your vehicle.