The 85th 24 Hours of Le Mans () was a 24-hour automobile endurance race for 60 teams of three drivers in Le Mans Prototype (LMP) and Le Mans Grand Touring Endurance (LMGTE) cars. It was held from 17 to 18 June 2017 at the Circuit de la Sarthe, near Le Mans, before 258,500 spectators. The race's 85th running, organised by the Automobile Club de l'Ouest, was the third of nine rounds in the 2017 FIA World Endurance Championship. A test day was held two weeks earlier on 4 June.

Earl Bamber, Timo Bernhard, and Brendon Hartley drove a Porsche 919 Hybrid to victory, taking the lead in the final two hours. It was Bamber and Bernhard's second Le Mans victory, Hartley's first, and Porsche's 19th. Toyota's Sébastien Buemi, Anthony Davidson, and Kazuki Nakajima finished eighth in a TS050 Hybrid after starting second, and were the only other competitors in the Le Mans Prototype 1 (LMP1) field to finish the race. Oliver Jarvis, Thomas Laurent, and Ho-Pin Tung of Jackie Chan DC Racing's Oreca 07-Gibson won the Le Mans Prototype 2 (LMP2) category; they led the race for nearly two hours in the closing stages before finishing second overall. The second DC Racing entry of David Cheng, Tristan Gommendy, and Alex Brundle finished third overall, three laps ahead of the Signatech Alpine of André Negrão, Nelson Panciatici, and Pierre Ragues.

The Aston Martin Vantage shared by Jonathan Adam, Daniel Serra, and Darren Turner overtook the stricken Chevrolet Corvette C7.R of Antonio García, Jan Magnussen, and Jordan Taylor in the final two laps to win the Le Mans Grand Touring Endurance Professional (LMGTE Pro) category for Aston Martin Racing. On the final lap, a Ford GT passed the Corvette to take second place for Pipo Derani, Andy Priaulx, and Harry Tincknell. The JMW Motorsport Ferrari 488 GTE shared by Robert Smith, Will Stevens, and Dries Vanthoor won the Le Mans Grand Touring Endurance Amateur (LMGTE Am) class. Spirit of Race's Marco Cioci, Duncan Cameron, and Aaron Scott and Scuderia Corsa's Townsend Bell, Cooper MacNeil, and Bill Sweedler completed the class podium for Ferraris in second and third.

Bamber, Bernhard, and Hartley took the World Endurance Drivers' Championship lead from Buemi, Nakajima, and Davidson by 17 points. Jarvis, Laurent, and Tung moved to third after their LMP2-class victory. Derani, Priaulx, and Tincknell stayed first in the GT World Endurance Drivers' Championship, with Adam, Serra, and Turner's category win, moving them to second. Porsche overtook Toyota to lead the World Manufacturers' Championship by 28.5 points, as Ford passed Ferrari for the GT World Endurance Manufacturers' Championship lead with six races left in the season.

Background The FIA World Motor Sport Council confirmed the date for the 2017 race at a press conference held by race organiser Automobile Club de l'Ouest (ACO) on 16 June 2016 at the Musée des 24 Heures du Mans. The event was held for the 85th time at the Circuit de la Sarthe from 17 to 18 June 2017, and the third of nine scheduled rounds of the 2017 FIA World Endurance Championship (FIA WEC). The race was scheduled to avoid clashes with other major motorsport events, which occurred in 2016 (when it was held the same day as the ).

Before the race, Toyota drivers Anthony Davidson, Kazuki Nakajima and Sébastien Buemi led the World Endurance Drivers' Championship with 50 points17 more than second-place Timo Bernhard, Earl Bamber and Brendon Hartley, and another five more than Neel Jani, Nick Tandy and André Lotterer in third. Toyota led the World Manufacturers' Championship with 69.5 points, 7.5 ahead of second-place Porsche. Ford Chip Ganassi Racing's Pipo Derani, Andy Priaulx and Harry Tincknell led the GT World Endurance Drivers' Championship by two points over AF Corse's Sam Bird and Davide Rigon, and Ferrari led Ford by seven points in the GT World Endurance Manufacturers' Championship.

Regulation and circuit changes Following the 2016 race, when the lead car failed to complete the final lap and was eventually not classified in the final results, the standards for car classification were changed by the ACO. Instead of the mandatory six minutes for the race's final lap, penalties were assessed on a graduated scale for any lap exceeding six minutes. Failure to complete the race's final lap in under fifteen minutes no longer led to a car being classified.

The event's slow-zone system was also revised, with nine dedicated slow zones around the circuit. Previously, individual marshal posts were used to mark the beginning and end of slow zones. The dedicated zones were located so the beginning of is in a slow section of the circuit; previous slow zones could begin in areas of the track where cars were required to slow down from high speeds, causing accidents.

The circuit was modified from the Porsche Curves to the Ford Chicane. The run-off area where the last right-hand turn goes into the left-hand corner, which begins the Corvette corner, was widened, with the barrier at the Porsche Curves moved further back. The angle of the wall at the left-hand entry to the short straight before the Ford Chicane was also altered. The Le Mans Prototype 2 (LMP2) category was revamped with the introduction of a single specification engine from Gibson, with increased power output compared to 2016 LMP2 cars. Cockpit and chassis designs mimicked the Le Mans Prototype 1 (LMP1) regulations for safety. The four approved chassis manufacturers were Dallara, Ligier, Oreca and Riley.

Entries Automatic invitations Teams which won their class in the 2016 24 Hours of Le Mans or won championships in the European Le Mans Series (ELMS), Asian Le Mans Series (ALMS) and GT3 Le Mans Cup (GT3 LMC) earned automatic invitations. The 2016 ELMS Le Mans Grand Touring Endurance (LMGTE) championship runner-up received an automatic invitation. The ACO gave two participants selected from the IMSA SportsCar Championship (IMSA) automatic entries, regardless of performance or category. When teams received invitations, they were allowed to change cars (but not their category) from the previous year. The LMGTE-class invitations from the ELMS and ALMS allowed a choice between the Pro and Am categories. ELMS' Le Mans Prototype 3 (LMP3) champion was required to field an entry in LMP2, and the 2016–17 ALMS LMP3 champion could choose between LMP2 or LMGTE Am. The 2016 GT3 LMC champions were limited to the LMGTE Am category. The ACO issued its initial list of automatic entries on 23 January 2017.

+Automatic entries for the 2017 24 Hours of Le Mans Reason invited LMP1 LMP2 LMGTE Pro LMGTE Am 1st in the 24 Hours of Le Mans Porsche Team Signatech Alpine Ford Chip Ganassi Team USA Scuderia Corsa 1st in the European Le Mans Series (LMP2 and LMGTE) G-Drive Racing Aston Martin Racing 2nd in the European Le Mans Series (LMGTE) JMW Motorsport 1st in the European Le Mans Series (LMP3) United Autosports IMSA SportsCar Championship at-large entries Keating Motorsport Scuderia Corsa 1st in the Asian Le Mans Series (LMP2 and GT) Algarve Pro Racing DH Racing 1st in the Asian Le Mans Series (LMP3) Tockwith Motorsports – or – Tockwith Motorsports 1st in the GT3 Le Mans Cup TF Sport

Entry list and reserves

In conjunction with announcing entries for the 2017 FIA WEC and the ELMS seasons, the ACO announced the full 60-car entry list for Le Mans and two reserves. In addition to the 28 guaranteed WEC entries, 13 entries came from the ELMS, six from IMSA and eleven from the ALMS; the rest of the field was filled with one-off entries only competing at Le Mans. The ACO initially named two cars to the reserve list; RLR MSport later withdrew their LMP2 Ligier, and a fourth entry (from Proton Competition) was not promoted to the race. Audi Sport Team Joest's withdrawal from LMP1 reduced the class to six entries for the race.

Garage 56 The Garage 56 concept, which began in 2012 to test new technology at Le Mans, was to be continued by the ACO. Welter Racing intended to enter a three-cylinder prototype vehicle powered by biomethane fuel, stored in cryogenic tanks which could withstand very low temperatures, to concentrate and maximise fuel volume. Due to funding issues, the car was not entered in the race.

Pre-race balance of performance changes The ACO and the FIA altered the balance of performance (BoP) in the two LMGTE categories in an attempt to eliminate sandbagging. To reduce performance, the Ford GT received a minimum weight increase and reduced turbocharger boost across all RPM levels. The Aston Martin Vantage was made heavier with an air restrictor elongated by , and the Chevrolet Corvette C7.R had less fuel capacity and its air restrictor lengthened by . Porsche's 911 RSR received a minimum weight increase of , and its air restrictor was lengthened by . The LMGTE Am-class Porsche 911 RSR's ballast was increased by ; the Ferrari 488 GTE and Aston Martin Vantage's ballasts were decreased by and , respectively. All three cars had minor power and restrictor adjustments.

Testing

On 4 June, the circuit held two mandatory four-hour sessions as part of a pre-Le Mans testing day. The morning session, held on a dirty track with lap times improving throughout, was led by pre-race favourite Toyota; Nakajima's 8 car lapped at 3:20.778. The second Toyota of Kamui Kobayashi was almost seven-tenths of a second slower, and José María López's No. 9 car was third. Porsche were more than two seconds slower than Toyota, and completed the LMP1 field with Bernhard fourth and Lotterer fifth. Oreca 07s led LMP2 with 13 cars leading the time sheets, led by André Negrão's No. 36 Signatech Alpinethe sole driver to lap below 3 minutes 30 seconds with a 3:29.809 lap, ahead of Rebellion and Graff. Corvette led LMGTE Pro with Jan Magnussen's lap of 3:55.726, followed by Patrick Pilet's No. 91 Porsche and the second Corvette of Oliver Gavin. Matteo Cairoli's No. 77 Porsche led LMGTE Am from Andrea Bertolini's DH Racing Ferrari.

Toyota led the second session with Kobayashi's 3:18.132 lap, followed by Buemi and López. Porsche remained slower than Toyota, with their best lap coming from Bamber's No. 2 car, followed by Jani's No. 1 entry. Nelson Panciatici's No. 35 Signatech Alpine lapped faster in LMP2 than Jean-Éric Vergne's No. 24 Manor and Alex Brundle's No. 37 Jackie Chan DC Racing entry to lead the sole LMP1 privateer (Dominik Kraihamer's No. 4 ByKolles Racing ENSO CLM P1/01). Gavin missed 91 minutes due to a mid-session engine change but set the day's best LMGTE Pro lap (3:54.701) towards the end of the test, beating Frédéric Makowiecki's No. 92 Porsche. Aston Martin led LMGTE Am with Pedro Lamy's 3:58.250 lap from Fernando Rees' Larbre Compétition Corvette. Erik Maris' No. 33 Eurasia Motorsport Ligier JS P217 stopped the session by becoming stranded in the gravel trap in the Dunlop Curves. Paul-Loup Chatin's No. 17 IDEC Sport Ligier and Jan Lammers's Racing Team Nederland Dallara collided at the second Mulsanne Chicane, but both continued without major damage. The session ended less than 15 minutes early when Roberto González's No. 25 Manor laid oil on the track and stopped.

Post-testing balance of performance changes After testing, the FIA re-adjusted the BoP. The LMGTE Pro-category Corvettes had their performance lowered with an air-restrictor reduction. The Aston Martins, Ferraris, Fords, and Porsches received fuel-capacity increases to equalise refuelling times and stint lengths. The LMGTE Am-class Aston Martin and Ferraris increased their fuel capacity, with the Ferraris receiving turbocharger boost pressure increases.

Practice