The decision made by the FIA and race organiser the Automobile Club de l’Ouest, which jointly formulate the rules for the WEC, covers only the double-points round of the series on 10-11 June.
It has resulted from an “in-depth evaluation of tyre usage data together with the WEC’s exclusive tyre suppliers, Michelin and Goodyear”, according to a statement issued by the ACO on Thursday.
“The exemption is limited to the Le Mans only, ensuring that drivers of all experience levels will be able to compete in the safest possible environment regardless of track conditions and temperatures,” it continued.
This will allow a period in which “tyre manufacturers, teams and drivers will gain valuable time to develop better understanding of how to bring cold tyres up to temperature ahead of the remainder of the 2023 WEC season”.
The reversal of the rule covers all three classes, Hypercar and GTE Am where Michelin is the sole tyre supplier and LMP2 in which Goodyears are used.
Temporary reversal of the ban on pre-heating follows the concerns raised by drivers over the course of the Spa 6 Hours meeting earlier this month following a series of accidents in which drivers went off the track on cold tyres.
The highest profile of the incidents were those suffered by Toyota driver Brendon Hartley and Ferrari’s Antonio Fuoco in the Hypercar class.
Hartley crashed his Toyota GR010 HYBRID at the top of Eau Rouge on his out-lap in qualifying, while Fuoco lost his Ferrari 499P on the old pit straight as he left the pits.
Ferrari sportscar racing boss Antonello Coletta suggested in the immediate aftermath of the race that it was “time to do some serious thinking on the matter because it has major ramifications for safety”.
Toyota driver and team principal Kamui Kobayashi was also critical of the ban, calling it “crazy dangerous”.
The FIA issued a statement on the day of the race after coming in for criticism that described the ban on the pre-heating of tyres as “a much-needed step from a sustainability point of view”.
It stressed that tyre warmers were not allowed in other series, including endurance racing, in a clear reference to the IMSA WeatherTech SportsCar Championship.
The latest statement from the ACO pointed out the ban on tyre warmers was “introduced as part of a long-term WEC tyre road map, developed in consultation with tyre manufacturers, and has been in the works over the past two years”.
A 100% sustainable fuel supplied by WEC exclusive supplier TotalEnergies will be mandated for use in the ovens the teams use to pre-heat the tyres at Le Mans.