Auxiliary springs: safe and comfortable driving

Passenger cars sometimes suffer under the weight of the caravan and holiday luggage. They sag considerably in the rear springs, which can even cause the caravan to hit the ground, for example at speed bumps. MAD, a specialist in auxiliary springs, proves that it can be different.

How often do you see it on the highway: cars sagging heavily at the back, under the pressure of the caravan. This is not only caused by the nose weight (55-75 kilos). Also the rest of the holiday luggage that has found a place in the car. Add to that the two children in the back seat and you understand that the rear suspension of the car can 'bottom out' at speed bumps, bumpy country roads or a slightly too enthusiastically taken bridge.

At such moments, the drawbar of the caravan can hit the road, sometimes even resulting in damage. Cars loaded in this way also have poor road handling: the pressure on the front wheels (steering!) is less, the combination feels less stable and the braking distance is greater. Such an unsafe situation can be prevented simply – and relatively cheaply. With auxiliary springs.

Two extra coils

A set of auxiliary springs consists of two extra coils that are placed within the existing coils of the rear suspension. Due to their construction, they only engage when the car is loaded. This works as follows: if a car in normal condition has a spring travel of ten centimeters, such a car sometimes sinks 5 centimeters deeper under the pressure of luggage and a full back seat. Auxiliary springs ensure that these 5 centimeters are compensated, so you have the same spring travel available as during normal use.

The auxiliary springs thus assist the normal rear suspension of the passenger car in carrying the total weight. With a caravan attached, your car will therefore not steer lighter, remain stable and bottom out less often when the car is heavily loaded. So much for the theory. But how does that work in practice?

Test driving with auxiliary springs

MAD is a Dutch manufacturer of auxiliary springs. During the MAD Xperience in Veenendaal, we were able to test drive two identical car/caravan combinations, both loaded in exactly the same way. Not overloaded for the occasion, but as we would go on holiday ourselves, assuming a family with two children plus accompanying holiday luggage. The ANWB uses 100 kilos for holiday luggage (such as awning, spare wheel, gas bottles, etc.), plus 30 kilos of personal luggage per person: together with bicycles, camping furniture and groceries for a few days, you are already quite close to the maximum load the caravan is allowed to carry.

Stable without swaying

The difference between both combinations was already clearly visible when stationary: the Peugeot-without was already heavily sagging in the rear springs, while the Peugeot-with was about 4-5 centimeters higher on its rear legs; comparable to an unladen state. During a route with speed bumps, road plateaus (at intersections) and bridges, the difference between both combinations became clearly noticeable. Literally. With the Peugeot/Hobby-without, we regularly hit the ground with the caravan nose – especially at speed bumps and road plateaus – even when we carefully reduced speed.

With the combination with MAD auxiliary springs, we never hit the ground. Not even when we increased our speed. Also during fast-driven sections in the polder, the combination with MAD auxiliary springs felt clearly more stable, in contrast to the swaying of the combination without auxiliary springs. Highly recommended, therefore. But then: the price.

Price is surprisingly good

The price of a set of auxiliary springs for passenger cars is surprisingly good. Auxiliary springs are relatively inexpensive compared to other solutions for heavy loads. A set of auxiliary springs for most mid-range cars costs about 170 euros, including VAT. Add half an hour of workshop rate to that and you're done for less than 200-220 euros. For the vast majority of cars, auxiliary suspension is sufficient – for some models, such as the Volvo V60, a replacement spring is necessary. Then you'll be more expensive: 350 euros, plus an hour and a half in the garage.

Also for motorhomes

MAD also makes auxiliary springs for motorhomes, consisting of air bellows that are mounted to the existing suspension. The air springs are filled with a special compressor and can even be adjusted while driving with a control panel on the dashboard: hard or soft, completely as desired. An advantage of auxiliary springs at the rear is that the weight of a scooter or two electric bicycles is automatically compensated because the central control unit puts the rear suspension under slightly more pressure.

Not strictly necessary, but optional: auxiliary springs at the front. These – especially in combination with air suspension at the rear – ensure a silky smooth ride, without the motorhome swaying. Air suspension is not cheap: expect € 1,800 at the rear and a similar amount at the front. Especially for motorhomes on Fiat Ducato, MAD also supplies reinforced front springs. These provide more ground clearance and prevent the motorhome from bottoming out less quickly at the front.

More information can be found atwww.hulpveren.nl