Guide: The optimal chassis for your motorhome
If you are planning to purchase a motorhome, there are an incredible number of points to consider. In many cases, it is primarily visual details that play the decisive role in the end. However, if you want to travel not only in a ‘good-looking’ and practical, but also in a comfortable and safe motorhome, you should definitely think about choosing the right chassis. Often underestimated, the quality of the chassis ensures that you and your family don’t end up wobbling about and will get to your destination safely and securely.
But how does a chassis actually work, and what constitutes a really good chassis? Read on for the most important information on the topic.
Chassis basics
Structure and individual components
When referring to the Fahrgestell or chassis, we are talking about the load-bearing part of a vehicle – the section on which the body, along with engine and gearbox, is mounted. The chassis forms the foundation of every vehicle frame.
The chassis comprises all components that make up the vehicle technology. These include elements that serve to absorb shocks, such as suspension systems and shock absorbers, as well as the wheel guidance including suspension, wheels, wheel bearings, axles, brakes and, of course, steering.
Safe travel
This means your motorhome chassis, axle, wheel suspension, and suspension system, in particular, all need to perform their task effectively. A good chassis can, for example, have a positive impact on driving stability and compensate for potential weaknesses of a motorhome, such as a long rear overhang and a high centre of gravity.
High-quality shock absorbers and suspension, as well as their perfect interaction, also characterise a first-class chassis. They ensure stability not only in corners, over bumps, or when the vehicle is unevenly loaded. In order to keep the vehicle at the same level while driving and absorb even severe shocks as efficiently as possible, both need to work together harmoniously. The suspension absorbs movement energy, while the shock absorber counteracts it, dissipating that energy so that vibrations do not cause the vehicle to sway.
If all chassis components are perfectly matched, this positively affects the vehicle’s handling, road holding, and thus the overall safety of your motorhome.
Comfortable travel
In addition to providing safety, a chassis must also offer the possibility of relaxed driving and a certain level of comfort. This is not always achievable with standard chassis. The reason for this is that the motorhome body is, in most cases, built onto the chassis of a light commercial vehicle, typically a Fiat Ducato as the base vehicle.
There is essentially nothing wrong with using such a light commercial vehicle chassis as the base for a motorhome cabin. Light commercial vehicles are designed as robust, low-maintenance utility vehicles with heavy-duty chassis to reliably transport heavy loads. Most transporters use rigid axles with leaf springs and additional shock absorbers, which fulfil these requirements. They are durable and dependable. However, comfort is often compromised with these standard chassis, which shouldn’t be a surprise since, as mentioned above, they are built for work, not for luxury. If comfort and relaxed travel are a priority, standard chassis are therefore not the first choice.
Chassis specialist AL-KO VT recognised this issue nearly 40 years ago and has been offering a chassis ever since with which you can travel not just safely, but also in great comfort. The AL-KO VT chassis, paired with optimally matched suspension and damping technologies, can maximise comfort on your travels.
How the AL-KO VT chassis differs from conventional standard chassis
Well over a quarter of a million motorhome chassis fitted in travel vehicles come from AL-KO VT. One of the decisive advantages – then as now: These chassis are both wider and lower than the original frame. In this way, not only the driving characteristics of the motorhome are improved, but also safety and comfort are increased.
Another crucial point is the in-house axle with torsion bar suspension fitted as standard in AL-KO VT chassis. It turns shocks and impacts into gentle vibrations, making it superior to conventional suspension technologies.
AL-KO VT chassis offer improvements for motorhome enthusiasts
- Low centre of gravity: Improved handling, better driving characteristics, increased driving safety
- Vehicle can be winterised: The lowered frame allows for double-floor installation, required for winter insulation.
- Lower body design: Less wind resistance, lower fuel costs, increased safety
- More comfortable travel: The standard axles with torsion bar suspension and independent wheel suspension deliver greater comfort and enhanced road holding in AL-KO VT chassis.
- Longer service life: The hot-dip galvanisation of the chassis offers long-term protection from corrosion and damage.
- Lightweight design: Reduced fuel costs or, alternatively, increased payload through a chassis that is 100 kg lighter
What determines the quality of a chassis?
In short: A high-quality chassis allows you to travel both safely and comfortably. It should also be resilient against weather and environmental factors, promising durability in the long term.
The suspension system, as part of the chassis, plays a major role in driving safety and comfort. Unfortunately, standard suspension systems often offer little comfort. Instead of prioritising a comfortable ride, conventional suspension tends to focus on durability and high load capacity. This results in familiar issues, such as rattling crockery and a chassis where you feel every little bump. In extreme cases, springs may lose their elasticity altogether due to years of continuous use.
There are, however, some effective ways to retrofit your motorhome with advanced suspension systems. At AL-KO VT, you’ll find a wide selection, from mechanical to pneumatic solutions. Suitable suspension systems are available for not only AL-KO VT chassis, but also for motorhomes with standard chassis:
Front or rear axle optimisation
AL-KO VT Comfort Suspension (ACS)
The ACS comfort strut replaces the standard strut on the front axle and consists of a special damper and a coil spring. Driving shocks are cushioned, steering precision, road and roll stability, and therefore overall driving safety, are improved.
AL-KO VT Level Controller
With the ALC, the optimal driving level of the rear axle is guaranteed, regardless of load, ensuring the required ground clearance at the rear as well as traction at the front wheels. It also compensates for differences between the driver's and passenger's sides, keeping trim and centre of gravity consistent even when the load is unevenly distributed.
Rear axle air suspension upgrade
This typically refers to an additional air suspension system. It is fitted in addition to the leaf springs and takes on part of the load-bearing task. It prevents suspension bottoming out and, in addition to more comfort and better driving performance, also offers practical settings such as several centimetres of rear lift, for example to assist with boarding a ferry. Air suspension systems can be retrofitted to many vehicles.
AL-KO VT Air Plus
With the manual additional air suspension Air Plus – for AL-KO VT chassis only – the air pressure in the suspension bellows is regulated manually, flexibly adjusting ground clearance and departure angle according to the load and road conditions. This system reduces rattling at the rear axle and provides better overall trim of the vehicle.
Equipping the vehicle with full air suspension
This system uses air bellows either on both front and rear axles, or solely on the rear axle, with the suspension being handled fully automatically. This ensures the vehicle always has optimal road holding and riding comfort.
AL-KO VT Air Premium X2
The Air Premium X2 full air suspension system is operated via remote control and enables automatic levelling of the rear axle in the event of uneven loading. The vehicle thus benefits from increased ground clearance and an improved departure angle – or can be lowered at the rear to enable comfortable loading. The Air Premium X2 is maintenance-free and can be upgraded to Air Premium X4 at a later date if required.
AL-KO VT Air Premium X4
The automatic Air Premium X4 full air suspension is fitted to both the front and rear axles, marking it as the top-of-the-range among suspension systems. The X4 automatically and independently aligns your vehicle during driving or while stationary, regardless of load. With the 'off-road function', up to 12 cm of diagonal height adjustment can be achieved. This system too is maintenance-free and protects the vehicle’s body structure. Like its 'little brother' the X2, the X4 is suitable for vehicles equipped with ESP.
Find out more
No matter which solution you choose, it is a worthwhile investment. All travellers benefit from a noticeably smoother, more relaxed ride. And it’s an important safety factor, when your vehicle can be handled simply and comfortably regardless of road conditions.
If you would like more information as to which solution might be right for you and your vehicle, please feel free to contact us – the AL-KO VT experts will be happy to advise you!
