A deep look into the effects of banning tyre warmers in the FIA World Endurance Championship.

The effects of the championships ban on tyre warming in 2023 were visible on track as we reflect on the FIA World Endurance Championship TotalEnergies 6 Hours of Spa and look ahead to the Centenary running of the Le Mans 24 hour race in June, but is this dangerous or something that will add another facet to the FIA World Endurance Championship.

To begin with, the FIA has determined that, for environmental reasons, tyre heating must be discontinued. It was customary in the World Endurance Championship (WEC) for up to three sets of wheels and tyres for LMP1 cars to be warmed in 'cabinets' simultaneously, reaching temperatures of roughly 90°c for slicks and 60°c for wets. These cabinets were often heated by massive diesel/kerosene burning blast heaters that ran for hours on end, using roughly 5L of fuel per hour due to the fact that teams were not permitted to use tyre blankets like in F1. It is estimated that about 15,000 litres of fuel will be burned to heat tyres during the 24 hour Le Mans race (not counting practice, test day or qualifying). It has to be said that all classes warmed their tyres in this manner.

Though this shift had been planned for at least two years on the WEC tyre roadmap, some drivers were caught off guard by its full effects at Spa, including Brendon Hartley in the No. 8 Toyota Gazoo Racing GR010 in qualifying and Antonio Fuoco in the No. 50 Ferrari 499P in the race. Despite the addition (for 2023) of an additional formation lap, it was clear during the wet circumstances with a track temperature of 11°c that several drivers were battling with the weather and low tyre temperatures, as many cars left the track during the formation lap.

Antonello Coletta, Head of Attività Sportive GT said following the Spa race: “Starting from the assumption that the rules are the same for everyone and that we abide by them, I think we need to reflect on the ban on tyrewarmers. It’s a common opinion in the paddock and among professionals, not to mention the drivers, that this situation has become dangerous. At Spa, there have been many accidents and extreme episodes due to cold temperatures and changeable weather, and it’s time to do some serious thinking on the matter because it has major ramifications for safety. We are on the eve of a decisive race like the 24 Hours of Le Mans where, overnight, temperatures are low and speeds very high. It’s not just an issue for us. The accidents involved different cars, from different classes, driven at the time by both professional and gentleman drivers, and this situation had already been predicted some time ago.”

We contacted the FIA and asked whether they planned to review the use of tyre warmers in light of the events at Spa and the possibility of cold nighttime temperatures at Le Mans.

The FIA's Director of Circuit Sport, Marek Nawarecki, told us "Moving away from tyre heating was a much-needed step from a sustainability point of view and something that the FIA Endurance Commission agreed on as part of a long-term WEC tyre road map. It is important to remember that already for a number of years, there have been several motor sport series, including endurance racing series, around the world that do not rely on tyre warmers. The nature of every incident is different, and each case has to be looked at before any conclusions are made."

In addition to the extra formation lap and the fact that Michelin were permitted to bring a third compound of tyre (usually 2) to Spa, the Race Director informed the drivers during the drivers briefing that each car leaving the pits, will deploy white flags on the onboard displays of each car behind approaching in the oncoming direction to help them adjust to starting on cold tyres. White flags were placed on the trackside panels on Friday FP3 to help warn drivers of vehicles leaving the pits.

The LMP2 field, who exclusively use Goodyear tyres, did not appear to be affected as much by the lack of grip from cold tyres, while the Michelin drivers were particularly affected.

Mike McGregor, Endurance Program Manager, Goodyear Racing, explains how the rule change will affect races: “It’s an exciting new challenge for drivers and teams to get a handle on. From our perspective, it’s likely to mix up the field from race to race and increase strategic opportunities.

“The effect of this rule change will differ dramatically from circuit to circuit. In warmer climates such as Sebring and Bahrain, tyres should reach their optimal operating window within two laps. However, in colder races there will be a more considerable difference. Drivers will need to balance overdriving the tyres in the first few laps as pressures stabilise.

“The surface of the tyre will be more important to manage during the opening laps, and with the total allocation unchanged since last year, the first few laps of tyre warm-up will be crucial, as this has a huge impact on tyre pressure and, ultimately, how much grip a driver feels. During races, the overcut will be more powerful, as too will be extending stints to decrease the number of pitstops needed, particularly at Le Mans.”

The LMGT3 class, which Goodyear will provide beginning in 2024, will replace the LMGTE-spec vehicles that have competed in the FIA World Endurance Championship (WEC) since the series' inception in 2012. The new GT class will utilise the same GT3 technological framework already in use by the FIA and will maintain its traditional emphasis on gentleman drivers.

In the United States, the IMSA WeatherTech series has never used tyre warming, and Michelin has supplied tyres that have performed well in near-freezing temperatures at Daytona. On speaking with Ben Keating (Corvette Racing) recently he told us that he saw racing in the IMSA series an advantage over other drivers in the LMGTEAm class until they got used to heating up their tyres.

However, the ban on tyre warming appears to be permanent, so it will be up to the teams and drivers to figure out how to generate heat in the tyres without breaking the rules. This could include adjusting setup in terms of suspension and especially damping.

We will be discussing this further on our next Podcast, along with a full race re-cap and a quick look forward to Le Mans.