Supersonic!

Imagine the sound: eight production trucks roaring around the corners of famous European racetracks like Germany’s Nurburgring, reaching speeds up to 160kph on the straight. What with their mass and engine output – up to 1,470kW, more than a Formula 1 racing car – their progress around the track is awesome to behold.

“Anyone who has experienced truck races live knows the fire in their hearts when the engines start. Absolute concentration, team spirit, tension and pure adrenaline,” says Silvia Lenz, a member of SL Trucksport 30, a team in the FIA European Truck Racing Championship. The team is sponsored by, and supplied by, Haldex, and competes head-to-head with about 20 others during half a dozen race days spread over the summer and autumn.

Race days consist of two qualifying and two super-pole sessions, and, to keep things interesting, there’s a reversed grid in race two and four for trucks positioned first and eighth in the previous race. For those used to Formula 1 racing, one of the biggest surprises for a first-time attendee would be the open paddock and access to the individual teams and drivers. “It's just one big family,” remarks Lenz. In the case of SL Trucksport 30, that’s literally true, as the driver is her son: Sascha Lenz.

He drives a 2020 MAN TGX 18.480 truck fitted with standard Haldex truck brakes, augmented with a water-based cooling circuit. But his runs, unlike those of a truck driver delivering goods on public roads, are accompanied by an extraordinary attention to detail. Lenz explains: “After every race day and between the individual runs, the truck is serviced, as the stress on the material such as the brakes and chassis is enormous, and ultimately the driver's safety also depends on it. He also needs full confidence in his brakes if he initiates the braking process 50m before the start of a bend. After all, five tonnes also wants to be controlled by a hairpin curve.”

The minimum tractor weight is 5.3t, with 60% of that on the front axle. As series-produced trucks were never designed for this kind of activity, extra care must be taken with the chassis. She adds: “The centre of gravity of a truck is quite high, and at the same time undesirable for racing. It requires a very high degree of sensitivity in the weight distribution, as this is also prescribed by the regulations and must not be undercut.”

The racing rules also keep these powerful vehicles looking like trucks, as they are required to maintain many production dimensions and features, including the fifth wheel, brakes (albeit with extra cooling, and split in two separate circuits for safety), axles, steering and transmission (ZF 16S 221 Ecosplit). In addition to MAN, other participating tractor manufacturers are IVECO, Freightliner, MAN, Scania and Ford Otosan. A standard cab is fitted, but with an internal safety cage. Other safety extras required for racing include emergency engine shutoff buttons, reinforced windscreen, quick-release steering wheel, shielding around the propshaft, tilting cab lock, sideguards and six-point racing seatbelt.

The maximum engine size allowed is 13L, and it must be series-produced (SL Trucksport 30 uses a six-cylinder MAN D 2676 RT). Camshaft timing and profile can change, but valve lift must remain standard. In addition, teams are fined if the engine produces visible smoke or exhaust. In 2021, the rules have allowed the use of biofuel (HVO, hydrotreated vegetable oil) in place of diesel for the first time. SL Trucksport’s race model also includes a Sachs coupling, Bilstein shock absorbers and Goodyear 315/70 R22.5 tyres.

Specifying and running this racing rig is neither cheap nor easy, admits Lenz. She says: “Like everything in life, it's a question of money, and success in the front ranks comes at a high cost. Further developments take time, but like everything in life, standing still means going backwards. No matter how hard you try to coordinate starts and racing scenes, in the end everything turns out differently than expected. During the race, it is a fraction of a second in which the driver has to recognise situations and decide an action.”

As to how the team chose Haldex, she observes: “The contact was made on the racetrack, and it just worked right from the start. Over time, a friendship has developed, as well as a regular exchange of data of the race-proven brake parts from Haldex. Our relationship should not be understood as pure sponsorship; rather, it is a win-win situation that offers advantages for everyone involved. Brakes can of course be tested on test stands, but theory and practice are two different worlds. Because where would the limits be higher than on the racetrack?”