Formula 1 is scheduled to remain running 18-inch tyres when the sport undergoes its radical overhaul in 2026 amid Pirelli’s choice to oppose a switch to 16 inches.
The last substantial overhaul to the technical regulations in 2022 saw F1 upgrade from 13 to 18 inches to ensure the series would become more road-car relevant.
An additional change to resize the rims to 16 inches in 2026 was under review as the FIA strives to reduce the weight of the cars compared to the current generation.
However, Pirelli is reported to have turned down that proposal on the grounds that such a change could be viewed as a regression on the subject of technology transfer.
Furthermore, it is also believed that Pirelli was reticent towards the extensive production it would have to put in place to manufacture new tyres for a testing programme.
Autosport has stated that the outcome was sought from a recent meeting of the technical advisory committee as the teams and the FIA conversed on the 2026 rules.
Although the choice has not been communicated as an official decision, it is thought that the 18-inch tyres will be retained with modifications to the tyre size and shape.
“We are close to the final version of the sizes,” Pirelli F1 boss Mario Isola told Autosport.
“Obviously when you design the wheel, you have to consider all the package, brakes, wheel, suspension, tyre, so I believe we are close to the final sizes.
“We have to change because the new car is different, and in any case, we have to design a smaller tyre.
“The discussion is between 16 and 18-inch tyres. And our preference is to stay on 18-inch tyres. And I believe that there are valid reasons to stay on 18-inch, with smaller tyres, but still the same rim.
“That’s what we are discussing, just a bit smaller diameter, a slightly lower profile and slightly narrower tyre.”
The weight of the cars has been a topic of concern among drivers in recent seasons, resulting in the FIA aiming to ensure the next machines are lighter and smaller.
But while Pirelli has refused to accommodate a switch that would aid that pursuit, Isola has deemed that a move to 16-inch rims would not make a sizeable difference.
“There is an element that is weight,” he added. “And clearly that affects all the package, and also the wheels.
“The difference between 16 and 18 and a narrow 18 is not huge. So the weight element is there.
“But it’s not the only element. There is an element of performance. Because obviously if you were to go to 16-inch tyres, much smaller, the risk of overheating is much higher. A smaller diameter means that you disperse the heat in a different way.
“And so there are many elements that if we wanted to design a tyre that is in line with drivers’ expectations. For performance, the 18-inch tyre is better than the 16.”
