Despite its name and strong resemblance to the streamlined 1952 W194 Le Mans racer and the iconic 1954 300SL Gullwing road car it spawned, the 1955 300 SLR was not derived from either. Instead, it was based on the wildly successful 2.5-liter straight 8-powered 1954–1955 Mercedes-Benz W196 Formula One champion, with the engine enlarged to 3.0 liters for the sports car racing circuit and designated "SL-R" for Sport Leicht-Rennen (eng: Sport Light-Racing). All were the work of Daimler-Benz's design chief Rudolf Uhlenhaut.
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 pace notes used in modern rallying. Teammate Juan Manuel Fangio was second in a sister car.
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 an additional 1-2-3 world championship win 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. Further non-championship trophies were also scored at the Eifelrennen in Germany and Swedish Grand Prix.
However, these impressive victories became overshadowed at Le Mans when the once again leading 300 SLRs were withdrawn after a horrific accident involving a team car driven by Pierre Levegh. Even with the innovative wind brake, the car's drum brakes had been unable to prevent Levegh from rear-ending an Austin-Healey, causing his vehicle to become airborne. Upon impact, the ultra-lightweight Elektron bodywork's high magnesium content caused it to ignite and burn in the ensuing fuel fire. An uninformed race fire crew initially tried to extinguish it with water, only making it burn hotter. Eighty-four spectators and Levegh lost their lives in the highest-fatality accident in motorsport history. Mercedes withdrew from racing at the end of the 1955 season and would remain withdrawn for three decades.
Daimler-Benz made two road-legal 300 SLR coupés, known today as Uhlenhaut Coupé. One of these two cars once served as the personal car of its designer, Daimler-Benz motorsport chief Rudolf Uhlenhaut, hence the name.
Before the Le Mans accident, he had ordered two of the nine W196 chassis built to be set aside for modification into an SLR/SL hybrid. These were intended to race in the Carrera Panamericana, which was canceled because of safety concerns following the Le Mans disaster. 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.
Before the project could be seen through, however, Mercedes announced a planned withdrawal from competitive motorsport at the end of 1955, in the works even before Le Mans. The hybrid program was abandoned, leaving Uhlenhaut to appropriate one of the leftover mules as a company car with only a sizeable suitcase-sized muffler added to dampen its near-unsilenced exhaust pipes.
With a maximum speed approaching 290 km/h (180 mph), the 300 SLR Uhlenhaut Coupé quickly earned the reputation of being the era's fastest road car. A story circulates that, running late for a meeting, Uhlenhaut roared up the autobahn from Munich to Stuttgart in just over an hour, a 137 mile/220 km journey that today takes two-and-a-half.
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. With its unflappable handling through corners, it treats the laws of centrifugal force with apparent disdain."
One Uhlenhaut Coupé has been preserved by Mercedes-Benz and is displayed at its corporate museum in Bad Cannstatt. Its only sibling was sold from the museum in May 2022 to a private collector for EUR 135 million ($142 million), with the proceeds used to establish the Mercedes-Benz Fund. The price was the highest ever paid for a car at a private sale or public auction.
Text Source: Wikipedia