Le Mans 24 hours, an iconic race beloved by motorsport fans throughout the world enters its 82nd year this coming weekend in what is set to be another corker of a battle.
Legends such as Graham Hill, Bob Wolleck, Derek Bell and Steve McQueen having raced over the years resulting in this endurance race not only pulling the crowds but also the cream of the racing driving crop looking to fulfil childhood dreams.
Five different categories of vehicles from pioneering LMP1 to hybrid vehicles the 8.4 mile track offers many challenges to both driver and vehicle. Top speeds of around 205mph means drivers need to keep their whits about them as they tackle the many challenging corners whilst negotiating their way around a starting grid of 56 vehicles.
Tyres are the only thing between the car and the track so unsurprisingly they form an important part of the whole package in endurance racing. Here are a few pointers as to what’s our good friends at Dunlop are doing to help their teams win and with more Le Mans wins than any other tyre manufacture they know a thing or two!
Le Mans varies from the other rounds of the World Endurance Championship in many ways, but one key difference is the contrast in track surface. The public road sections of track have a highly polished surface due to the hundreds of thousands of cars and heavy goods vehicles that use the route on all but the days of the Le Mans 24 Hours. The rubber particles and diesel spillages make the track even less ‘grippier’ than the race circuit bespoke tarmac. While Dunlop’s compounds separately can handle any condition, each one is also designed to handle Le Mans where grip levels can be dramatically different at different parts of the lap.
Although the Le Mans track is low on the abrasion scale, durability is an important factor because of the long straights. Cars are set up with camber to go faster through the corners (the contact patch is larger and the tyre has more grip from the increased track/tyre contact) but that has knock-on effects for the straights. The tyre has a reduced contact patch with camber settings which is good in that rolling resistance is decreased giving higher speeds. The down-sides are that the inner shoulder of the tyre sustains increased force from the high downforce loads and the reduced contact patch means that the tyre has less contact with the surface so runs at a cooler temperature. Coming off the straight and going into corners means that the tyres could be ‘too cold’. Dunlop has focused on designing the compounds and constructions of the endurance tyres to warm up more quickly to counteract the impact of the cooling from the straights and ensured that the construction is strong enough to cope with the demands.
Downforce creates drag which slows teams down, particularly on straights, so teams are looking to reduce the downforce that they need to create the grip to get round corners. At Le Mans, the teams run bespoke aerodynamic packages with an emphasis on straight-line speed. Dunlop helps teams compensate for lower downforce set-up by having an increased contact patch and compounds that maximize grip.
Tyre manufacturers are permitted three dry-weather compound tyres for the World Endurance Championship. All three are permitted at the Le Mans round but those three must be able to perform in a wide variety of conditions – from 4°C at Silverstone to 40°C in Texas. Temperatures at Le Mans drop at night and can easily reach lows in the order of 4°C but grip levels are different on the French track. At Silverstone the teams ran medium and hard compounds in the cold but at Le Mans in the cold conditions the soft can be a better option, particularly in the cool of the night. The important factor in the tyre design is achieving as wide an operating window as possible so that as conditions change the tyre still gives drivers the ability to set good lap times.
So the car’s at the track and the tyre specifications are fixed – what’s left to do? The right compound for the right conditions is important but so too are the correct pressures for each tyre for each car. Car set-up and driver styles are all different. There will be subtle differences between every combination – even between the three drivers in one car. One of Dunlop’s biggest strengths is the relationship between our tyre engineers and the team engineers. Each team is given a recommended tyre set-up before each race to suit the chassis, track and drivers. Together, throughout the weekend, the set-up and tyre pressure settings are optimised to get the best performance possible for the team for the circuit temperatures and conditions. If the pressure is too high a ‘balloon’ effect reduces the contact patch significantly and the centre of the tyre wears quickly as it is doing all the work. Too little pressure effectively transfers the contact to the outer edges creating more friction and the tyre shoulder wears too quickly with performance affected.
Wow, that’s a lot of considerations to take in when producing tyres for one of the most challenging races in the world. Bet you learned something new there!
But what about the drive itself? With cornering ability being a considerable factor in lap times drivers have to be on the ball. In these fascinating guides from writer, journalist, driver coach and racing driver, Mark Hales we can help give you the inside track.
Now you should be all set for this fascinating race. So grab a cuppa, print off this handy spotter guide, sit back, relax and enjoy watching racing legends in the making.