What makes up these racing leviathans?
Although it may sound silly, it is important to note that Racetrucks don’t compete with a trailer attached. A question that has been asked… In fact in the early days of the sport during the mid 1980s, the majority of competitors were actually racing road-going trucks. The Italian winner of the very first Donington event arrived with a fully loaded trailer, unhooked it, collected the silverware – and on Monday morning was back on the road to deliver his load.
But the sport has moved on a great deal in the past two decades and the machines used nowadays are a far cry from their road-going cousins. Just as in every form of motorsport the main objective when preparing a Racetruck is to make it go faster, but truck racing also has some regulations that make it equally important not to go too fast.
"A Racetruck is faster than a Porsche 911 to 100mph"
Due to the sheer size and weight of these speedy six-wheelers - minimum weight limit is 5500kgs - right from the beginning of the sport a maximum speed limit of 100mph (160km/h) was enforced for safety reasons.
One side-effect of this rule is that the racing tends to be extremely close. No-one can run away into the distance purely because of a superior top speed. Of course this places a premium on acceleration and braking – something a modern Racetruck excels at.
The 12-litre turbocharged diesel engines used by the majority of the field are tuned up to produce in excess of 1000 horsepower, which is more than double the output of even the most powerful road version. Combined with the vast torque figure of over 3000Nm, this gives the Racetrucks amazing straightline performance.
From a rolling start - standing starts are not used in truck racing - a Racetruck is capable of out-accelerating a Porsche 911 up to 100mph. It’s stopping power isn’t too shabby either; thanks to water-cooled disc brakes and six, super-sticky racing tyres.
Of course, when on a track barely wide enough to place two of these vehicles side-by-side, the task of overtaking becomes pretty tough, especially when the entire pack is equipped with the same potent machines and the same desire to defend their position.
Bump and grind...
Officially, Truck Racing is a non-contact formula, but the truth is that bumps, scrapes and exchanges of paintwork are a regular part of the action and just as in Touring Car racing it’s this physical aspect of the sport that helps to attract enormous audiences.
In the early days of the formula the main means of increasing engine performance was to tune the fuel pump and increase airflow by installing an enormous turbocharger, or two. Nowadays the modern diesel engines are all electronically programmed, so the help of a factory trained engine technician with a lap-top computer to programme the engine management system is essential in order to run at the front.
Vast increases in power and beefed-up brakes help the Racetrucks to perform in a straight line, but what about getting around the corners? The engine is significantly improved for competition use, but the 12-litre lump also plays a major role in improving the Racetruck’s handling and road-holding.
All the front-running teams take advantage of a ‘loophole’ in the regulations that allows them to move the engine position, so the traditionally very front-heavy truck ends up with a virtually mid-engined layout. The rules specify a minimum front axle weight of 3300kgs – so there is a limit to how far back the engine can be moved.
"It's like driving a block of flats from the sixth floor"
The FIA regulations for the Racetruck category also insist that the original standard production chassis is retained, although reinforcing subframes is allowed to strengthen and stiffen the chassis to make the axles function better. Combined with shortened suspension travel and racing shock absorbers, which are adjustable to suit varying circuits and conditions, the latest Racetrucks have much higher cornering speeds than their predecessors.
Although all the major components sit low in the chassis, the standard truck cab is retained, which means the driver is still sitting high up – more than a metre from the ground. This is always a shock for experienced car racers getting behind the wheel of a Racetruck for the first time, as they tower above the circuit.
One ‘guest’ driver described his first outing in a Racetruck as “like driving a block of flats from the sixth floor...”
There are obviously many other minor ‘tweaks’ employed by the top teams to give their driver a slight edge over the opposition – but essentially a Racetruck retains the major components and overall appearance of the original tractor unit, similar to a touring car.
The other vital modifications to any Racetruck are those concerned with safety. The rules oblige all competitors to fit a full roll cage, safety harness and racing seat. Fortunately this equipment is rarely tested as, despite their top-heavy appearance, Racetrucks tend to carry their weight very low down and it’s very unusual to see one roll. The other compulsory piece of equipment you’ll spot on every Racetruck is an external engine cut-out switch, which is standard practice in all motorsport categories.
Choosing which make of truck to compete with is obviously a commercial decision for some…and a straightforward will-to-win for others.
German-made MAN trucks currently appear to have a clear advantage in terms of outright performance, particularly in the engine department. With a professional service team of factory technicians on hand at every event, armed with a complete set of spares, there is no doubt that MAN is the marque setting the standard.
Fortunately there is some increasingly serious opposition taking to the grid with machinery from Mercedes-Benz, Renault and Foden among others helping to bring some colourful variety to the track. And with a field of up to 30 starters in some races there’s no shortage of action.