For almost a century, the 24 Hours of Le Mans has urged manufacturers to innovate for the benefit of future motorists.

The quest for performance has always embraced reliability and safety.

The ground-breaking innovations of the past have shaped today’s commitment to sustainable mobility.

MissionH24, which aims to bring hydrogen to the 24 Hours of Le Mans in 2025, exemplifies a strategy for the future that has its roots in a fertile history.

We invite you to delve into this history.

1922: Road surfaces

At a time when the future 24 Hours circuit was just a set of dirt tracks, a new surface was laid on the Mulsanne Straight.

It combined chalk chippings with a tar/bitumen emulsion which was itself covered with tar-coated grit.

By 1926, the entire circuit was surfaced.

A technique that paved the way to today’s hard-wearing roads.

1925: Body design aerodynamics

Engineers rapidly grasped the benefits of a streamlined body.

In 1925, the Chenard & Walcker Tank laid the foundations for aerodynamic research.

The quest for improved drag coefficient (Cx) produced iconoclastic vehicles such as the rebodied Cadillac Coupé DeVille, dubbed “Le Monstre”, that was entered in the 1950 race.

In the 70’s Porsche designed a car body inspired by the wing of an aircraft, the 917 “Kurzeck” (“short-tail”) which carried off the distance record in 1971 when it travelled 5335.31 km.

The record stood until 2010 when it was eclipsed by Audi.

1925: Body design aerodynamics

1926: Fog lamps

It is not unusual for a part of the circuit to be shrouded in mist as dawn breaks.

To overcome this problem, Lorraine-Dietrich engineers added a third lamp in the centre of the grille, earning the car the nickname “Cyclops”.

Nonetheless, it probably contributed to their landslide victory: the three B3-6s took the top three places as the Robert Bloch/André Rossignol pairing exceeded a distance of 2,500 km.

1926: Fog lamps

1927: Front-wheel drive

In the early years of the race, the architecture of the cars doing battle was quite standardised: front engine and rear-wheel drive.

In 1927 however, Maurice Fenaille, a French industrialist, financed an innovative project pioneered by Jean-Albert Grégoire, a multi-talented driver and engineer.

He designed a front-wheel-drive car known as the Tracta.

It finished seventh in its first appearance at the 24 Hours of Le Mans.

The road version of the Tracta was produced until 1934.

That same year, Citroën introduced the principle on the vehicle it named Traction.

1927: Front-wheel drive

1949: Rear engine

According to Enzo Ferrari, “horses pull the plough, they don’t push it”.

It is rather ironic then that the first rear-engined car to win at Le Mans was a Ferrari 250 P in 1963.

But it was not the first of its type to start the race.

That particular honour goes to a Renault 4 CV, prepared and entered by a gentleman driver, Camille Hardy, against the advice of the company, which considered the car unsuitable.

Unfortunately, it retired with engine trouble.

1949: Rear engine

1951: The radial tire

This innovation was not specifically invented for the 24 Hours of Le Mans, but the race helped forge its reputation by providing a useful testing ground.

In 1951, Michelin fitted a Lancia Aurelia B20 GT with radial tyres, the patent for which had been filed just five years earlier.

The introduction of textile cords into the tyre’s carcass strengthened the sidewalls and thus improved solidity and roadholding.

Shod with the Michelin X, the Italian car topped the S 2.0 class and finished twelfth overall.

1951: The radial tire

1952: Direct injection engine

The eternal conundrum – how to boost performance while controlling fuel consumption?

In 1952, Mercedes introduced a system – originally developed by Bosch for aircraft – that was capable of improving the efficiency of petrol engines.

Petrol was injected directly into the combustion chamber, avoiding fuel losses and optimising combustion.

The famous 300 SL with gull-wing doors was equipped with this technology when it won in 1952.

1952: Direct injection engine

1953: Disc brakes

Progress in racing car performance brought a new necessity to light: improving braking efficiency and endurance.

It was Jaguar that came up with the solution by equipping its C-Types with a revolutionary piece of technology: disc brakes, a solution originally developed for aircraft landing on aircraft carriers, helping the British make to finish first and second in the 1953 race.

The idea was subsequently adopted by Citroën on the pioneering DS and is still used today on all production cars.

1953: Disc brakes

1962: Quartz iodine headlamps

Night-time accounts for around eight hours of the 24-hour race. Bordered by forest, a large part of the circuit is plunged into absolute darkness.

Effective lighting can therefore make all the difference.

In 1962, Ferrari installed halogen headlamps using iodine vapour on the 330 TRI/LM for the very first time.

The test proved conclusive as the beam range was doubled and, consequently, halogen headlamps were fitted to all cars from 1965.

1962: Quartz iodine headlamps

1963: Gas turbine engine

In 1957, the constant aim to boost innovation saw the creation of a new class reserved for gas turbine-powered cars.

A 25,000-franc prize was offered for exceeding a distance of 3,600 km.

In 1963, BRM fielded a strange-looking model powered by a gas turbine engine and fitted with a 220-litre kerosene tank.

It was certainly a showstopper with its distinctive whistling noise, but as it was in violation of the rules, it failed to classify.

Yet it managed to finish in seventh place... unofficially.

1963: Gas turbine engine

1967: Slick tyres

Michelin brought a major innovation to the racing world when it invented “slicks” – tyres with a smooth tread, providing greater traction on a dry track. The results were immediately obvious as the #46 Alpine A210 driven by Vinatier/Bianchi became the first P 1.6 car to lap in under four minutes while winning the class.

1967: Slick tyres

1967: Aerodynamic appendages

How can the downforce essential to stability at high speed be increased other than by working on the body design?

The answer to this question came from Chapparal who introduced the first rear wing on its 2F prototype.

The oversized wing – as wide as the car – looked rather comical as it sat perched high above the rear end.

Chapparal had also designed a pedal system to adjust its angle for different parts of the circuit!

The active rear wing was born.

1967: Aerodynamic appendages

1970: Rotary engine

A rotary engine is recognisable by the barely bearable screeching noise it makes.

The technology was introduced in 1970 on a Chevron-Mazda, powered by a 200 bhp, 983 cc twin-rotor engine which failed just four hours into the race.

In 1991, however, the architecture came good in spectacular fashion.

With a disastrous performance by the Peugeots, and Mercedes, Jaguar, and Sauber all in trouble, Herbert/Weidler/Gachot drove the Mazda 787B and its rotary engine to victory, also representing the only Le Mans victory by a Japanese make.

1974: The turbo engine

The idea of supercharging through an exhaust-driven turbocompressor appeared in 1962 in the United States on the Chevrolet Corvair Monza.

BMW brought the innovation across the Atlantic, adopting it on the 2002.

Porsche used it at Le Mans from 1974, winning the race in 1976 with the 936.

1974: The turbo engine

1998: The hybrid engine

American Don Panoz was the brains behind the idea of a hybrid engine design combining internal combustion technology and an electric motor.

His Esperante GTR-1 Q9 was powered by a Ford 6.0 engine supported by an electric motor with the batteries being recharged by a regenerative braking system.

Despite this technology, the Panoz Q9 failed to qualify for the race.

Nonetheless, hybrid technology became a must-have by 2012 with the Audi R18 e-Tron.

1998: The hybrid engine

2006: Racing diesel

Since it was invented in the late 19th century, the diesel engine has always been associated with commercial and utility vehicles as it appears to be more at home under a truck bonnet than in a racing car.

However technical developments such as direct fuel injection, increased pressure and turbos have boosted performance and cut fuel consumption.

The first diesel-powered car to appear at the Le Mans 24 Hours was a Delettrez in 1949, but victory only came in 2006 when Audi took the honours.

2006: Racing diesel

2011: LED headlamps

LED (Light-Emitting Diode) headlamps, increasingly popular on production cars, made their first appearance at Le Mans in 2011 on the Audi R18 TDI.

In addition to offering high lighting quality, this process uses less electricity, weighs less and is more compact than halogen systems.

It also creates a unique lighting signature at night.

In 2014, Audi went a step further by introducing laser lights that offer even higher performance.

2011: LED headlamps

2025: Racing hydrogen

In 2018, the Automobile Club de l’Ouest announced the creation of a hydrogen class at the 24 Hours of Le Mans in 2024.

The MissionH24 programme revolves around the development of a prototype designed by GreenGT and has attracted support from sector-leading partners helping to explore the world of electric-hydrogen propulsion and map out the future of motorsport.

Red Bull and Oreca have also shown considerable interest in the ACO’s hydrogen programme and, in early 2021, proposed their respective services and know-how to the project. They will supply the chassis of the future Hydrogen prototypes that will take to the 24 Hours of Le Mans track from 2025.

2025: Racing hydrogen