A fully packed motorhome puts different demands on its suspension from an empty van. Water, luggage, bikes and equipment all add weight, often towards the rear. A suitable motorhome air suspension kit can provide adjustable rear support, help reduce sag and improve comfort and stability when correctly set for your load.
This guide focuses on semi-air suspension, also called air assist suspension or auxiliary air suspension. These systems support your existing suspension rather than replacing it with a full-air conversion.
What does an air assist suspension kit do?
A semi-air suspension kit adds air springs between the chassis and rear suspension using brackets designed for the vehicle. The air springs, sometimes called air bags or helper springs, work alongside the original springs. Adjusting their pressure changes the additional support they provide.
A typical kit includes two air springs, mounting brackets, airline tubing and inflation controls. Depending on the system, pressure is adjusted using an external air supply or an onboard compressor. Independent systems let you adjust the left and right sides separately.
Full-air suspension is a different type of upgrade: it replaces the original springing and may include automatic ride-height control. An onboard compressor or digital pressure gauge alone does not mean a system automatically levels the vehicle.
The main benefits of motorhome air suspension
1. Improved driving comfort
Correctly adjusted air springs can help the rear suspension cope with travelling loads, reducing excessive compression and helping the vehicle feel more settled over uneven roads. This can make longer motorhome and campervan journeys more comfortable.
Results depend on the vehicle, its existing suspension and the kit settings. More pressure is not always better: excessive pressure can make the ride firmer. The aim is appropriate support for the load, within the kit's specified limits.
2. Improved stability under load
Additional rear suspension support can help a loaded motorhome feel more stable. Where a kit has independent air circuits, different pressures can accommodate uneven loading between the two sides.
This is useful when fixed equipment, such as furniture or a water tank, places more weight on one side. Air assist does not replace correct loading, suitable tyres or maintaining the original suspension.
3. Less rear sag
If the back of your campervan sits lower when loaded, helper air springs can help restore a more suitable rear ride height. They share some of the suspension load with the original springs, providing extra support for travelling equipment.
Rear sag should still be checked for underlying causes, including worn suspension or excessive loading. A vehicle that looks level is not necessarily within its permitted weight limits.
4. Adjustment for changing loads
Your suspension requirements may change between a short weekend break and a longer trip with a full garage. Adjustable air spring pressure lets you alter rear support to suit those changes, rather than relying on one fixed setting.
A manually inflated system offers a simple way to adjust pressure before travelling. An onboard compressor makes adjustments more convenient, particularly when your load changes regularly.
5. Help with levelling on uneven ground
On suitable independent systems, separate left and right adjustment can help make small levelling corrections when parked. The adjustment available depends on the load, suspension travel and kit limits.
Semi-air suspension is not a replacement for levelling ramps or hydraulic levelling jacks on a significantly sloping pitch. A shared air circuit also cannot provide independent left and right adjustment.
Choosing between Basic, Standard and Comfort kits
The right air suspension system depends on how you want to adjust it, as well as which hardware fits your vehicle. When comparing Martech kits, check the selected product and compressor option rather than assuming every kit includes the same controls.
- Basic kits: a simpler option for additional rear support and ride-height adjustment. A shared circuit does not provide separate left and right pressure control.
- Standard kits: independent circuits with separate pressure monitoring. Check whether your selected option includes a compressor.
- Comfort kits: independent adjustment with an included compressor and up/down switches for convenient pressure changes.
- Electronic gauge and remote control options: alternative ways to monitor or adjust the system. Check the product description for the exact functions supplied.
Where a choice of control panel is available, consider where it will fit inside the vehicle. Universal box, flat and flush panels have different mounting requirements; a dedicated dashboard panel must match the relevant dashboard design.
How to find an air suspension kit that fits your motorhome
Start with the base vehicle rather than just the motorhome conversion name. Fiat Ducato, Peugeot Boxer, Citroën Relay, Ford Transit and Volkswagen Crafter applications can vary by year and chassis configuration.
Before ordering, check:
- Make, model and compatible years for both the suspension hardware and any dedicated control panel.
- Drivetrain: front-wheel drive, rear-wheel drive or four-wheel drive.
- Rear wheel layout: single or twin rear wheels.
- Chassis and rear suspension type: including whether the vehicle has an AL-KO chassis.
- Handbrake type and existing modifications where these affect the application.
Where a product page includes an underside fitment photo, compare the bracket mounting area and suspension layout with your vehicle. Bump-stop colour and the distance to the axle can differ, so use the full specification rather than appearance alone.
Use the Martech kit finder to narrow down the options, then confirm the details on the product page before ordering.
Can air suspension help with motorhome up-plating?
Installing an air suspension kit does not, by itself, increase your permitted gross vehicle weight, axle limits or towing capacity. An air spring's load rating is not an extra payload allowance.
A suitable suspension upgrade may form part of a formal motorhome uprating, also known as up-plating. SvTech's motorhome uprating guidance explains that requirements vary: some vehicles need paperwork and a revised plate, while others need suspension, wheel or tyre changes.
Ask an uprating specialist to assess your vehicle before buying a kit specifically for this purpose. Check the vehicle's actual travelling weight and individual axle loads, and continue to observe its current limits unless an appropriate uprating has been completed.
Installation and everyday care
Vehicle-specific brackets and clear instructions can make an air assist kit a practical DIY project for a competent owner with suitable tools and safe working facilities. Read the exact kit instructions first: mounting arrangements, fasteners and electrical requirements differ between applications.
Airlines need protection from heat, sharp edges and moving parts. Compressor-equipped systems also require suitable mounting and electrical installation. If any part of the job is outside your experience, use a qualified installer.
After installation, follow the specified leak checks, tightening requirements and pressure limits. Check pressure and inspect the air springs and tubing at the intervals given in the instructions. There is no single pressure setting that suits every motorhome or load.
Is an air suspension upgrade worth it?
Air assist suspension is worth considering if your motorhome needs more rear support, sits low when loaded or would benefit from adjustment for changing loads. The most useful upgrade is one that addresses your particular vehicle and how you use it.
Choose the correct fitment first, then the controls that suit you. Browse Martech air suspension kits or use the kit finder tool to find options for your motorhome or campervan.