25 years of BMW M5. Sheer understatement.

A quarter of a century ago, the BMW M5 was launched as the first generation. Aficionados like to think of this baby as the “Original M5”. This car was all about understatement and that’s how it remains today: The car’s debut, its profile, its accompanying documents. “On the basis of the proven BMW 5 Series, the engineers at BMW Motorsport GmbH developed a new, independent automobile, the BMW M5. The external appearance was virtually unchanged compared with the basic model but the M5 offers peak performance and superior driving potential.” This was the brief announcement BMW gave to the press in February 1985.

And the first official presentation of the exceptional new 5 Series car was just as understated as the written statement. BMW Motorsport GmbH presented its latest creation for the first time at the relatively low-profile international motor show in Amsterdam. There wasn’t even a presentation for a select circle of people, so that the auto press were already saying: “The car with the understated designation M5 is traded in almost as much secrecy as marijuana.”

In fact, the new enhanced 5 Series cars could only be distinguished from the outside if you looked extremely carefully: a set of 165 TR 390 aluminium wheels with 220/55 VR 390 tyres and two discrete badges at the front and on the boot lid. No other difference on the outside distinguished the cars from the volume 5 Series automobiles. The BMW M5 appealed through its inner values: Opening the engine bonnet revealed the splendour of the legendary four-valve, six-cylinder engine powering the M5. “Simply looking at the M engine left absolutely no doubt about its power, particularly since this engine seemed to come from an era when even the engineering of a car needed to espouse aesthetic values,” enthused one tester. “None of the broom-cupboard muddle present in lots of modern cars, but high-power precision engineering in an optically refined design. Anyone can experience the same enjoyment looking at this engine at rest as looking at a beautiful wristwatch.” The engine generated 286 b.h.p. at 6,500 revolutions a minute. The specific power was 83 b.h.p per litre with a displacement of around 3.5 litres, which was in the range of motor-sport engines at the time. Actually, it’s no surprise – that’s why the six-cylinder was developed.

The M88/3 – the designation for the advanced engine version in the BMW M5 – transferred its power through a reinforced five-speed gearbox to the rear axle. The high-power saloon had a limited-slip differential as standard in order to be in a position to transform the full 340 newton metres of rated torque generated by the six-cylinder power unit at 4,500 rpm into forward motion. The 3.5 litre engine had no difficulty propelling the 5 Series body weighting 1,430 kilograms. At full acceleration, the test stop watches recorded only 6.1 seconds before the car sprinted past the 100 km/h mark on the speedometer. After just 15 seconds, the speed was at 160 km/h.

Naturally, the racing engineers of Motorsport GmbH had ensured that the BMW M5 had an appropriate chassis including a robust braking system. The body was slightly lower slung, while tauter springs and single-tube pneumatic dampers delivered a more sporty driving style than the other 5 Series cars. The braking system had reinforced and enlarged discs at the front in the form of fixed-calliper disc brakes and sliding-calliper disc brakes at the back, and the system was decelerated by a specially designed ABS system. Four alloy wheels with 220/55 VR 390 tyres provided safe road grip. These were also unusual: The specially designed TRX tyres were intended stay on the rim even if a loss of pressure was experienced. Hence, they were the precursors of today’s run-flat tyres, which are designed to avoid flat tyres altogether.

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