F1’s TPC Rule Change: Teams Can Use 2025 Cars in 2026

A key regulation shift allows teams to test 2025 cars in TPC, raising questions over competitive balance amid looming 2026 engine supplier swaps.

Next year, Formula 1 teams will be allowed to use one-year-old 2025 cars for their Previous Car Testing (TPC) programs. The usual TPC regulations stipulate that only cars at least two years old can participate in these tests.

However, with the radical rule changes coming in 2026, 2025 cars will be permitted on test circuits next year. According to Auto Motor und Sport, this could disadvantage teams switching engine suppliers for 2026.

A clear example is Sauber, currently powered by Ferrari, which will become Audi’s works team from 2026. Ferrari would be reluctant to supply engines for the 2025 car, fearing that Audi could gain access to its V6 technology, even from an older generation—unless Sauber pays $5 million and allows Ferrari engineers to oversee operations in the garage.

Aston Martin is also changing engine suppliers for 2026, moving from a Mercedes customer unit to a Honda works engine. However, Mercedes reportedly has only one condition: Aston Martin must run its TPC program from an external facility with a separate team, clearly distinct from the race team supplied by Honda.

As for Alpine, whose cars are currently powered by Renault’s works engines, the Enstone-based team will switch to a Mercedes customer engine for 2026. It will continue using this engine for TPC, just as Red Bull has confirmed an agreement with Honda for these specific tests.

Scrapping of Narrower 2026 F1 Tires Imminent

Rumors from the Bahrain test paddock late last week suggested that teams were pushing to abandon Pirelli’s new, narrower tire dimensions for 2026.

Amid the speculation, Max Verstappen remained coy when asked how the development tires felt on track. “They’re round,” he said with a smile.

Mercedes driver George Russell, however, was more direct: “They are clearly worse overall, there’s no doubt about that. Because they are much narrower,” said the Briton.

Mercedes, in particular, is pushing for F1 to scrap the idea of narrower tires entirely and retain the current dimensions for 2026.

However, these dimensions were originally developed in collaboration with teams, who believed that reducing drag and weight would be ideal for the radically different 2026 cars.

Asked about the situation, Pirelli’s F1 chief Mario Isola stated: “If the majority of teams want to keep the current size, we will.” He explained that Pirelli could simply use the existing molds with the 2026 rubber compounds.

Yet, scrapping the narrower tires now seems unlikely, as some teams are already well advanced in designing their 2026 cars based on wind tunnel models using the initial tire specifications.