by Ross Finlay (10 Jun 03)

As it prepares for the launch this autumn of the Mercedes-Benz SLR McLaren, the Stuttgart company is looking back at the stunning machine which introduced the SLR model designation nearly 50 years ago. The old car and the new both demonstrate the use of race-winning technology in a super-high-performance road car, although there will be a lot more McLarens about than there ever were road-going coupé versions of the original SLR.

Mercedes is claiming that the McLaren SLR has "a level of rigidity and strength never before achieved in road-going vehicles", thanks largely to the transfer from Formula 1 to series production of carbon-fibre composites in the chassis and body construction.

The new car's engine is a majestic hand-built Mercedes-AMG supercharged V8, and its brakes feature fibre-reinforced ceramic materials offering extremely high heat resistance.

But there was also a great deal of high technology in the original sports-racing 300 SLR, carried over from the all-conquering W 196 Grand Prix cars which dominated the 1954 and 1955 Formula 1 seasons. In fact, the factory referred to the two-seater as the W 196 S.

The 2.5-litre straight-eight engine of the GP cars was enlarged to 2982cc, and its power output boosted to a maximum of 310bhp - that depended on the particular intake manifold fitted in SLR trim. Torque reached 233lb/ft at 5950rpm. If these figures seem unremarkable for a Le Mans-type car today, bear in mind we're talking nearly half a century back here.

Amazing Racing Record

Built for the 1955 season, the SLR wiped the floor with the opposition in the five races in which it had an uninterrupted run. Stirling Moss, with Denis Jenkinson reading the notes, won the Mille Miglia with the famous "722" car (pictured below). Fangio and Moss were first and second in the Eifelrennen at the Nürburgring, and repeated that performance in the sports-car Swedish Grand Prix. Moss and the American John Fitch shared the winning car in the Tourist Trophy race at Dundrod, with Fangio and Karl Kling second, and Taffy von Trips/André Simon completing the SLR hat-trick.

There was another one-two-three victory in the Targa Florio, with Moss and Peter Collins winning from the Fangio/Kling pairing, and Fitch sharing the third-placed car with Ulsterman Desmond Titterington.

Of course, there was a sixth date on the SLR calendar, the most disastrous motorsport event in the car's single racing season, and the biggest tragedy the sport has ever seen - Le Mans 1955, when "Pierre Levegh" (the pseudonym of French driver Pierre Bouillon) tried to take avoiding action as another car swerved into his path, only for his SLR to be launched towards the too-close spectator enclosure opposite the pits. More than 80 people, including the driver, were killed.

The accident had far-flung ramifications, not least in making race organisers the world over realise they would have to pay far more attention to spectator safety provision. In Switzerland, the authorities placed an immediate ban on circuit racing, which has never been lifted. And although they allowed the SLR to complete its season, the Daimler-Benz directors eventually decided to withdraw from racing altogether. It would be many years before Mercedes returned.

Uhlenhaut's Idea

Although the SLR had no further life except in museums and - more recently - in retrospective events (Moss will be at the wheel of "722" in a return visit to Goodwood during the Festival of Speed on July 11-13, and the car will also be at Hockenheim for the German GP on August 03), its designer, the very engaging Rudolf Uhlenhaut, had already come up with the idea of a closed version, meant for endurance races in which, as things turned out, it would never take part.

He had one built for himself - "my company car" as he liked to call it - and took it to the 1955 Swedish Grand Prix. With the same powertrain arrangement as the sports-racers, including the driveshaft from the clutch to the rear-mounted gearbox running under the driver's seat, super-lightweight Elektron bodywork and a cumbersomely silenced version (the Stuttgart police insisted) of the race engine, this was a phenomenal performer for its day.

For a magazine test, at 4 o'clock in the morning on a specially closed section of autobahn near Munich, it was timed at just over 180mph.

Mercedes actually built two of these "Uhlenhaut Coupés", but they never went into production. Had they done so, they would certainly have been the SLR McLarens of their day. In terms of 1955 performance norms compared with those of 2003, possibly even more than that.

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