The 300 SL traces its origins to the company's 1952 racing car, the W194, and was equipped with a mechanical direct fuel injection system that significantly increased the power output of its three-liter overhead camshaft straight-six engine.

The car's iconic gullwing doors and innovative lightweight tubular-frame construction contributed to its status as a groundbreaking and highly influential automobile.

The designation "SL" is an abbreviation of the German term super-leicht, meaning "super-light", a reference to the car's racing-bred lightweight construction.

Mercedes-Benz developed a new version for the 1953 racing season by replacing the M186's carburetors with fuel injection, and shifting to 16-inch wheels; the gearbox was installed on its rear axle.

The idea of Mercedes producing a toned-down Grand Prix car targeted to affluent performance enthusiasts in the booming post-war American market was suggested by the company's U.S. importer, Max Hoffman, at a 1953 directors' meeting in Stuttgart.

[4] Mercedes received a positive visitor response to both cars in New York, and production began at the Sindelfingen plant in August of that year.

The body consists mainly of sheet steel, with the bonnet, boot lid, dashboard, sill, and door skins made of aluminum.

The width of the tubular frame along the cockpit allowed the cabin roofline to be inset considerably on both sides, dramatically reducing the front area.

The car’s distinctive eyebrows are a functional feature in the front,[18][19] both physically and aerodynamically deflecting road water from the windscreen,[20] and stylistic in the rear, added for visual symmetry.

Like the racing Mercedes-Benz M194, the 300 SL borrowed the basic two-valves-per-cylinder M186 engine from the regular four-door 300 (W186 "Adenauer") luxury touring car introduced in 1951.

[5] It featured the M186's aluminum head: a 30-degree diagonal base, allowing larger intake and exhaust valves than a standard horizontal joint with the engine block.

The lowest final-gear ratio, 1:3.25, delivered a top speed of up to 263 km/h (163 mph) and made the 300 SL the fastest production car of its time.

Owners might block off airflow through the oil cooler and stick rigidly to the appropriately low 1,600 km (1,000 mi) recommended oil-change interval.

[28] Like modern racing cars, the 300 SL has a tubular frame, designed by Mercedes head engineer Rudolf Uhlenhaut and made of chrome-molybdenum steel.

The upper tube is so high it is level with the driver's elbow,[4] making conventional horizontally, hinged doors infeasible.

The recirculating ball steering was relatively precise for its time, and the four-wheel independent suspension allowed for a reasonably-comfortable ride and markedly-better overall handling.

The front suspension consisted of unequal-length double wishbones, coil springs, hydraulic telescopic shock absorbers, and a torsion anti-roll bar.

Being jointed only at the differential (not at the wheels themselves), the swing axle could make rear end cornering treacherous at high speeds or on bad roads due to extreme changes in camber.

The roadster variant of the 300SL made its debut at the Geneva Motor Show in March 1957 and began production that May, coinciding with the final assembly of the Gullwing coupes.

Similar to the coupe, the roadster utilized steel bodywork, with aluminum panels used for the hood, trunk lid, door skins, sills, floors, and bulkhead.

[4][30] Additionally, the rear suspension was enhanced with low-pivot swing axles, resulting in notable improvements in handling and ride comfort.

[31] A significant change to the roadster's design was the updated rear axle, which incorporated a single-joint arrangement with a pivot point 87 millimetres (3.4 in) below the differential centerline.

[33] The FIA sporting commission changed the rules for 1954 in October 1951, and the W195s could not compete;[33] the company began to develop a six-cylinder 300 SL for racing.

[36] Lang and Riess won the race with an average speed of 155.574 kilometres per hour (96.669 mph), and Theo Helfrich and Helmut Niedermayr placed second.

[36] The team concluded that the car's relatively-crude swing-axle rear suspension was already at its limit in transmitting power to the road, and the engine was less durable.

[36] A 1-2-3 finish might have been the final result, but American John Fitch was disqualified for allowing a mechanic to touch his car on the next-to-last day.

[36] The race team prepared a new version of the 300 SL for the 1953 season;[33] the 300 SLK would be lighter, with a shorter wheelbase, larger wheels, fuel injection, and better brakes.

The O'Shea-Tilp team used a lightened roadster with drilled front coil-spring mounts, no fan, a welded sheet-aluminum inlet manifold, and twin exhaust-pipe outlets.

The roadster (sometimes known as the SLS) won the 1957 Class D Sports championship with triple the points of its nearest competitor, Carroll Shelby's Maserati.

[41] Former Gull Wing Group International president Bob Sirna set a Bonneville Speedway F/GT three-liter sports-car speed record of 190.759 mph (306.997 km/h) in a modified coupé in 2016.