The Mercedes-Benz 300 SLR (W 196 S) is a two-seat sports racing car that took part in the 1955 World Sportscar Championship before a catastrophic crash and fire at Le Mans later that year ended its domination prematurely.

[1] The W 196 S's monoposto driving position was modified to standard two-abreast seating, headlights were added, and a few other changes made to adapt a strictly track competitor to a 24-hour road/track sports racer.

Company design chief Rudolf Uhlenhaut, architect of both the 300 SLR racer and the hybrids, appropriated one of the leftover mules as his personal car.

[3] In spite of its name and strong resemblance to both the streamlined 1952 W194 Le Mans racer, and the iconic 1954 300SL Gullwing road car it spawned, 1955 300 SLR was not derived from either.

[citation needed] Mercedes team driver Stirling Moss won the 1955 Mille Miglia in a 300 SLR, setting the event record at an average of 157.650 km/h (97.96 mph) over 1,600 km (990 mi).

He was assisted by co-driver Denis Jenkinson, a British motor-racing journalist, who informed him with previously taken notes, ancestors to the pacenotes used in modern rallying.

[citation needed] After missing the first two races at Buenos Aires in Argentina and the 12 Hours of Sebring in the United States, where Ferrari scored a victory and a second place respectively, the 300 SLRs later scored a decisive 1-2-3 finish in the Tourist Trophy at Dundrod, Ireland, and a 1-2 at the Targa Florio in Sicily, earning Mercedes victory in the 1955 World Sportscar Championship, two points ahead of Ferrari.

The resulting coupé featured a significantly more sculpted body than the 300 SL fitted over a slightly widened version of the SLR's chassis, with signature gull-wing doors still needed to clear its spaceframe's high sill beams.

The hybrid program was abandoned, leaving Uhlenhaut to appropriate one of the leftover mules as a company car with only a large suitcase-sized muffler added to dampen its near-unsilenced exhaust pipes.

With a maximum speed approaching 290 km/h (180 mph),[4] the 300 SLR Uhlenhaut Coupé easily earned the reputation of being the era's fastest road car.

[6] US auto enthusiast magazine Motor Trend road tested the car, as did two English journalists from Automobile Revue, who spent more than 2,000 miles (3,200 km) behind its wheel.

After a high-speed session at four o'clock in the morning on an empty section of autobahn outside Munich the latter wrote: "We are driving a car which barely takes a second to overtake the rest of the traffic and for which 120 mph on a quiet motorway is little more than walking pace.

The front windshield for the two-seater mode was originally steeply raked, but due to intense turbulence in the cabin this was redesigned repeatedly during testing at Hockenheim before Mille Miglia.

To prevent cornering forces from raising the car, as occurs with short swing axles, the rear used a low-roll centre system featuring off-centred beams spanning from each hub to the opposite side of the chassis crossing one-another over the centreline.

[7] In tests the 0.7 m2 (7.5 sq ft) light-alloy spoiler slowed the car dramatically and improved cornering, helping to compensate for the superior new disc brakes of the SLR's main rival Jaguar D-type.