The 1931 24 Hours of Le Mans was the 9th Grand Prix of Endurance that took place at the Circuit de la Sarthe on 13 and 14 June 1931.
With the demise of Bentley, the favourite for an outright victory was split between the Bugatti and Alfa Romeo works teams, with a lone privateer Mercedes as an outside chance. Once again it was one of the smaller fields, with only 26 starters.
At the start of the race it was the Mercedes setting the pace from the Bugattis of Chiron and Divo. But tyre-wear was a big issue, with many cars suffering tyre blowouts and punctures. This left Marinoni leading in the works Alfa. Coming up to the first refuelling stops, the rear tyre on Maurice Rost's Bugatti blew out at full speed on the Mulsanne Straight. Rost lost control of the car and went through a fence, hitting three spectators, killing one. When more tyre issues plagued Chiron's car, the Bugatti team withdrew their remaining two cars. Tyre troubles had also cost the Mercedes team eight laps.
The Alfa Romeo of British privateers Howe and Birkin had been having a reliable race. As others were delayed they caught them up and took the lead after midnight. At 2.30am a sudden thunderstorm swept the track. Zehender went off at Indianapolis doing damage that eventually forced the works Alfa's retirement in the morning. The Talbots of the British Fox & Nicholl team were running third and fourth with the Mercedes closing in again. Ivanowski was able to source some Dunlop tyres. He and Stoffel were able to pick up their pace, and when the leading Talbot was waylaid in the morning by chassis damage, the Mercedes was up to second by noon.
At the finish, Howe and Birkin won by seven laps from the Mercedes and the remaining Talbot. This was the first win at Le Mans for an Italian car, and in a record-breaking run, they claimed all three trophies – including the Index and Biennial Cup – and broke the 3000km distance for the first time. Only six cars were classified, which has been the lowest ever number of finishers in the 24-Hour race.
Regulations This year there were no changes to the racing regulations of either the AIACR (forerunner of the FIA) Appendix C rules, nor those of the Automobile Club de l'Ouest (ACO). The biggest change this year was in the pits. Rather than refuelling with 10-litre cans, a series of 4-metre high reservoir towers were built holding 1000-litres. Three hoses from each allowed gravity-replenishment at about 250 litres per minute. Shell once again had the fuel contract and again offered its three standard fuel options. The ACO also now allowed a mechanic to assist the driver with the refuelling.Spurring 2017, p.54
As usual, as engine power advanced, the ACO once again adjusted the Index target distances. Example targets included the following:Spurring 2017, p.360 Engine size 1930Minimum distance 1931Minimum distance Equivalent laps Minimumvehicle weight Ballast 6000cc+ 158.9 laps 1820 kg 180 kg 3000cc 146.1 laps 875 kg 120 kg 1500cc 138.1 laps 670 kg 120 kg 1100cc 128.4 laps 430 kg 60 kg 750cc 109.1 laps 430 kg 60 kg
Entries With Bentley in major financial strife, the works team had been disbanded and the Bentley Boys dispersed, marking the end of an era. Into this void came works teams from the two main powerhouses of current Grand Prix racing: Alfa Romeo and Bugatti. However, apart from Aston Martin, and a (non-eventuating) effort from Ariès the remaining entries were from privateer teams and "gentleman-drivers". There were still only 30 cars entered, not a great improvement on the record low number from the previous year. Of those, only four were entered in the final of the Biennial Cup – an Alfa Romeo, the two Talbots and the returning women in their Bugatti.Spurring 2017, p.53Clarke 1998, p.90-1: Motor Jun16 1931
Category Entries Classes Large-sized engines 17 / 15 over 2-litre Medium-sized engines 7 / 5 1.1 to 2-litre Small-sized engines 6 / 6 up to 1.1-litre Total entrants 30 / 26 Note: The first number is the number of entries, the second the number who started.
Daimler-Benz had pulled out of racing officially in 1930 leaving privateers to run their cars. In the 1930 race, the Mercedes of Rudolf Caracciola had taken the challenge to Bentley in the first half of the race. This year, Paris-based Russian Valériani-Vladimir Tatarinoff, entered an SSK (Super Sports Kurz) on behalf of fellow émigré Count Boris Ivanowski. He had previously been denied an entry of a stripped-down Alfa Romeo for the 1928 race. The SSK had a big 7.1-litre engine that could be augmented temporarily by a Roots supercharger up to 250 bhp.Spurring 2017, p.62-3 Along with his co-driver, Le Mans veteran Henri Stoffel, Ivanowski entered the car in both touring and Grand Prix races.Spurring 2017, p.60-1
Bugatti had run almost exclusively in Grand Prix racing with great success in the late 1920s. This year marked its first foray to Le Mans with a works team. The new Type 50 was a development of the big-engined Type 46. Its 5.0-litre straight-8 engine had a Roots supercharger and was capable of 250 bhp, and with a 3-speed gearbox, gave the car a top speed of 195 kp/h (120 mph). The team, managed by Bugatti's 22-year old son Jean, brought three short-wheelbase versions for their works drivers Louis Chiron / Achille Varzi and Albert Divo/Guy Bouriat, joined by Maurice Rost/Caberto Conelli.Clausager 1982, p.48-50 Perhaps anticipating bad weather, they were running on a new, heavy-tread Michelin tyre. Other innovations were a new quick-change brake system, "pop-top" petrol caps, and oil-refill tubes in the bonnet all designed to speed up pitwork.Clarke 1998, p.92-3: Motor Jun16 1931 Alongside the works team were three French privateer entries in smaller Bugattis, including wealthy Parisian bankers Pierre Louis-Dreyfus / Antoine Schumann who raced together under the pseudonyms "Ano-Nime"; and the women who charmed the media the previous year, Odette Siko and Marguerite Mareuse, returned.Spurring 2017, p.80-1
Alfa Romeo had achieved great success in recent years with the 6C model, in both its regular or supercharged format. Vittorio Jano's new design, the 8C, had a supercharged 2.3-litre engine that developed 155 bhp. It came in two styles: a short-wheelbase, 2-seater corto adapted for Grand Prix racing and narrow, tight circuits like the Mille Miglia; and a 4-seater lungo (long) version for the ACO regulations for touring cars. Although the Scuderia Ferrari ran the car for Italian races, it was a works team that arrived at Le Mans with two cars. The driver-pairings were team regulars Giuseppe Campari / Attilio Marinoni and "Nando" Minoia / "Freddy" Zehender.Spurring 2017, p.56-7 Two Englishmen were some of the early purchasers of the new model. Sir Henry "Tim" Birkin had given up his Blower Bentley project for the more reliable Alfa, and won his class first time up at the Irish Grand Prix the week before Le Mans. Earl Francis Howe had his delivered to replace his 6C that Achille Varzi had crashed in the 1930 Irish race. So in the 1930 Le Mans, Howe had run his Mercedes-Benz instead, earning one of the four entries taken up for the Biennial Cup. For this race, he approached Birkin to be his co-driver The Bentley 4½ Litre that Birkin had raced in 1928 (and then Earl Howe in 1929) had been purchased Anthony Bevan who bought it back for a third run at Le Mans.Spurring 2017, p.78 Since the previous race, the great brand had been sold to Rolls-Royce.Laban 2001, p.66
Unlike most other car companies, Talbot had been reasonably successful with sales of its 6-cylinder car range. Its latest version, the 105, now had a 3-litre capable of 120 bhp and 175 kp/h (110 mph), as well as a 4-speed gearbox and a bigger 160-litre fuel-tank. Four cars were made available to the Fox & Nicholl team. Two were taken to Le Mans to race with another as a test vehicle. The drivers were team-regulars Brian Lewis, Baron Essendon / Johnny Hindmarsh and Tim Rose-Richards / Owen Saunders-Davies.Spurring 2017, p.65-6
Henri de Costier had driven at Le Mans three times in the late-'20s. This year he organised the entry of a pair of big Chrysler straight-8s. He, himself, drove the larger 6.3-litre, 125 bhp, CG Imperial Eight while the new model CD Eight (with a 100 bhp 3.9-litre engine) was entrusted to the new, young French talent, Raymond Sommer.Spurring 2017, p.76-7
La Lorraine-Dietrich had not competed at Le Mans since 1926, after the company believed they were denied victory in the Biennial Cup by the ACO on a technicality. The team's four B3-6 Le Mans specials had been mothballed until one was sold to Henri Trébor, who got the car a few days before the race after a factory refit. Racing journalist Roger Labric submitted an entry on his behalf. Trébor engaged Louis Balart as his co-driver, himself a veteran of the first four Le Mans races.Spurring 2017, p.70-2 The small Scottish car company of Arrol-Aster arrived for its only foray at the race. The 17/50 had a 2.4-litre sleeve-valve engine with a Cozette supercharger. The car was prepared at Tim Birkin's race-garage in London.Spurring 2017, p.83
Aston Martin returned to Le Mans after a three-year hiatus with a works team of three cars. The 1.5-litre International was still in a limited run and only seven racing chassis had been made. Le Mans winner Sammy Davis was in hospital after a major accident at Brooklands at Easter so company engineer Augustus "Bert" Bertelli instead drove with Maurice Harvey. Former Lea-Francis drivers Kenneth Peacock and Sammy Newsome had the second car while Jack Bezzant and Humphrey Cook had the third.Spurring 2017, p.68-70
Voiturette racing was still popular and encouraged enthusiast engineers to make their own small customised specials. Yves Giraud-Cabantous was one such. A mechanic and driver at Salmson, he adapted a Salmson chassis with the oft-used 1.1-litre Ruby engine that put out 35 bhp. After successes in the Bol d'Or, Roger Labric encouraged him to enter the Le Mans race and offered to enter two under his name.Spurring 2017, p.72-3 After a disappointing race for BNC the previous year, when the new car didn't even turn a wheel, the team returned with the tried and tested 527 Sport, also with a Ruby engine.Spurring 2017, p.82
In 1930 George Eyston had approached Cecil Kimber, managing director of MG Cars, about developing the first 750cc car to break the 100mph barrier. In part, this was because his Land Speed Record rival, Malcolm Campbell was working with Austin for the same goal. With the resulting EX120 special, Eyston achieved the record in February 1931 at Montlhéry.Spurring 2017, p.74-6 Using the prototype's engine and frame, MG built the new C-Type. Fourteen cars, already pre-sold, were quickly built in time to take a clean sweep, first time out, at the Brooklands Double-12 (Britain's annual 24-hour event) in May. The result was repeated a month later at the Irish Grand Prix. A week later, two of the cars were entered for Le Mans, without superchargers. Francis Samuelson returned with his regular co-driver (and MG tester) Freddie Kindell, while Lady Joan Chetwynd ran her husband's car along with fellow C-Type owner Henry Stisted.
Practice A number of teams and drivers were racing the weekend before at events across Europe, which made preparations difficult. Arthur Fox, in one of his Talbots, gave Alfa drivers Birkin, Howe and Campari a lift to London from Dublin where they had all been racing in the Irish Grand Prix meeting.Spurring 2017, p.66-7
After their races the Bugatti team drove their cars across from Molsheim in eastern France, arriving on Thursday. In practice, one of the cars blew a rear tyre, so team manager "Meo" Costantini directed the drivers to not go above 4000rpm to limit their top speed for the first six hours.