Talking tyre technology at Le Mans
The Dunlop-shod G-Drive Racing entry competes within the LMP2 class
Racing around an 8.47-mile circuit for 24 hours places severe demands on the tyres used by sports car teams. Here’s how they cope
They say Le Mans can be won along with lost depending on how much time a car spends within the pits. which places special demands on the consumables of each racing car within the field.
Originally, tyres were changed at every fuel stop although the idea became apparent which a competitive advantage could be gained by tyres being used for more than one stint.
In last year’s 24-hour race, some competitors were able to use the same set of tyres for four successive 0-mile stints, even within the intense heat of the afternoon when the rubber runs at its hottest temperatures.
Spending less time within the pits than its rivals contributed to the Dunlop-shod Jota team winning the LMP2 category. Remarkably, This specific occurred in tandem with very little drop-off in performance: Dunlop’s engineers calculated which the lap average for fourth stints on the same tyres was 0.17sec slower than the average for stints when the rubber was fresher.
“The nature of the Le Mans circuit can be completely special,” says Matthew Rees, service engineer for Dunlop Motorsport with responsibility for the G-Drive Racing team’s Ligier-Nissan.
“the idea includes a multitude of track surfaces, through the permanent race track to the public road section. You also have to take into account factors such as race debris, oil along with deposits dropped through normal road cars on the public road section. In all, the demands on the tyres are fairly high.”
At the start of the earth Endurance Championship season each tyre any has to submit its compounds to the rule makers at the ACO.
“At the moment Dunlop has the soft, the medium along with the medium plus, in addition to intermediates along with wets for inclement weather,” says Rees. “A range of teams will be using the three variants across the whole of the Le Mans 24 Hours.”
Each LMP2 car has 16 sets of tyres at its disposal during the race. The performance of Le Mans prototypes can evolve dramatically during the course of the 24 hours. Britain’s Sam Bird, who shares the G-Drive Racing entry with Julien Canal along with Roman Rusinov, says the opening stints of the race will be crucial in understanding more about the level of tyre wear.
“We had restricted running in both test days, so we’re actually a little unclear on the exact life the tyre has. We know which the idea can be long, although we don’t know precisely how long,” he explains.
“So at the beginning of the race we will probably do a double-stint along with then change tyres so the guys at Dunlop can examine the rubber along with give us an exact reading on exactly how far they think our tyre will go while maintaining a Great speed.
“After we’ve found which information out, our pitstop strategy for the rest of the race will be more dictated by fuel rather than the tyres.”
There are also some techniques the driver can use to preserve the rubber for as long as possible. Bird says: “We speak about ‘spin time’, which means trying not to overwork the [driven] rear tyres. although because of the long straights at Le Mans, the tyres get to cool down quite a bit on each lap.
“Another thing which we could see through the front tyre during the race can be some cold graining, especially between 2am along with 7am within the morning.
“We could find which on the first lap, if you’re pushing too hard, especially on corners such as Tertre Rouge, you could start to overstress the skin of the tyre on the external along with grain the front left. This specific would likely mean you’re then going to have understeer for the remainder of your stint.”
Dreaded understeer can play a significant role in tyre management. Rees says: “If a car can be bottled up behind another car, the idea can pick up understeer due to the aerodynamic imbalance. So if you’re within the middle of a triple-stint along with the driver can be experiencing understeer, he can damage the tyres along with might have to pit early because the lap times could drop off.”
Although the idea’s inevitable which the tyres will wear out over the course of a long stint at Le Mans, any drop-off in lap times can be mitigated by some other factors, says Bird: “These tyres can maintain a Great level of grip for many laps along with although we might lose a little bit within the corners as the tyres wear, we gain on the straight because the vehicle gets faster as the fuel load decreases.”
An entire day of racing around such a long circuit inevitably means incidents, along with these can impact on some other cars at racing speeds. Le Mans tyres are fitted using a Type Pressure Monitoring System (TPMS) which informs the engineers back within the pit garage about any fluctuations in tyre pressure. This specific can warn a team about a potential slow puncture inflicted by debris on the track.
“We know through experience which the gravel traps along with run-off areas contain flint along with through all of the practice along with qualifying sessions we’ve seen cuts to the tyres. We’ve had no punctures caused by which, although we’re absolutely aware of which if a car goes off track along with brings the flint back onto the circuit,” says Rees.
Ultimately, Dunlop learns lessons on the circuit which can transfer back to its standard car tyre range. Rees says they especially look at “materials, compounds along with polymers” in terms of the technology transfer – which means running over a flint chipping in your road car shouldn’t spell the end for your rubber.
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