Amid struggles to get temperatures into Pirelli tyres that are new to the DTM for 2023, teams have come up with creative ways to circumvent the ban on using electric blankets.
According to Motorsport.com’s sister website Motorsport-Total.com, several teams have been found leaving the garage doors wide open and placing tyres in a way to take advantage of direct sunlight.
Teams also appear to have used tyre tents to heat up the Pirelli rubber. Some outfits use a black tarpaulin for this purpose, which can store more heat in direct sunlight than a white-coloured tent.
Another clever trick involves teams placing tyres early on the grid trolley, which happens to be positioned in the sun outside the pit.
These incidents were recorded most recently at the Lausitzring and the Sachsenring rounds and appear to be in contravention of the rules. Article 25.1 of the DTM regulations for the 2023 season states that "any device or measure to increase the tyre temperature above the ambient temperature is inadmissible".
For this reason, the DTM issued a clarification to the rules on Saturday evening of the Sachsenring weekend, preventing teams from using sun rays to heat up tyres.
"Exposing the complete wheels to sunlight is considered a measure to increase the tyre temperature above the ambient temperature,” it said.
“The only exception is the duration of the stay of tyres on trolleys on the grid. The teams are therefore obliged to make every effort to protect the wheels from sunlight.”
Speaking about the controversy, long-time Audi squad Abt said it had asked for a clarification from the DTM even before the start of the season.
"That was a very clear question from us: if the sun shines into the pit at an angle, do I have to put the tyres somewhere at the very back and bring them forward during the pit stop?" Abt sports director Martin Tomczyk told Motorsport-Total.com.
"We had one metre of sunlight into the pits. We then put the tyres in the shade and not in the sun at the front because that is not allowed."
Abt managing director Thomas Biermaier stressed that the clarification was important“ because you never have the same amount of sunshine in all the garages.”
While Abt adhered to the rules willingly, officials of the German Motorsport Federation (DMSB) had to go from pits to pits to reiterate the regulations to other teams.
With the DTM now issuing a clear-cut clarification to the rules, Abt is demanding penalties in case any team is caught using sunlight to heat up the tyres.
“Now there is no excuse," said Tomczyk. "If someone is caught now, then we need tough measures. That's what I expect, otherwise we don't need rules."
The issue of tyre heating could play a decisive role in the final four races at the Red Bull Ring and Hockenheim, where temperatures are expected to be on the lower end of the scale.
Torsten Schubert, whose eponymous BMW squad likely complied with the rules following the clarification at Sachsenring, said: "The tyre is there in a jiffy, you saw that in the outlaps. That will be a different issue when it gets a bit colder."
