Why can't F1 cars race in heavy rain? The reasons we rarely see full wet tyres

F1

What's wrong with F1's wet tyres? All too often heavy rain heralds a red flag in grands prix, before drivers even have a chance to put on the most extreme rubber. But that's not necessarily Pirelli's fault...

Ferrari of Carlos Sainz on wet tyres with plume of spray behind at 2022 Japanese Grand Prix

A plume of spray from Carlos Sainz's Ferrari in Japan '22 practice: heavy rain stopped the race for two hours

Ferrari

Formula 1 cars remain among the most technologically advanced on the planet, capable of cornering at incredible speeds and generating more downforce than even most fighter jets.

However, for all their engineering brilliance and incredible speeds, the current F1 single-seaters remain hopeless in one common condition: heavy rain.

As of 2025, F1 still faces major hurdles when it comes to racing on very wet tracks.

Despite new technology and ongoing innovations, the blue-walled “full wet” tyres remain a rare sight, with safety cars or red flags still halting grand prix weekends any time weather conditions become too extreme.

Here’s a breakdown of the continuing challenges and what (if anything) has improved since previous regulation changes.

The visibility issue

F1 uses two types of wet-weather tyres: the green-walled intermediates, designed for damp or drying conditions. These have shallower tread patterns that flex to generate heat and maintain grip on cooler surfaces where slicks would struggle. Then there are the blue-walled full wets, which feature deeper grooves to channel away standing water and maximize contact with the track in heavy rain.

The main factor behind F1 cars being unable to race in wet conditions is not grip, but visibility.

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When rain falls heavily, the modern Pirelli full wet tyres – used since the introduction of 18-inch wheels in 2022 – can still shift over 85 litres of water per second at 300km/h.

The increased tyre width (405mm vs pre-2017 325mm) and diameter, while great for water displacement, also multiply the problem of spray, reducing visibility far more than in previous eras.

For 2025, Pirelli introduced further tweaks to its wet and intermediate compounds. While the core construction remains similar (18-inch diameter), compound changes aim to reduce the performance gap between intermediates and full wets, and to limit overheating and degradation of the wet tyre.

While the displacement figures are phenomenal, the result is a towering rooster tail of spray kicked up behind each car.

Ground-effect aerodynamics, mandated since 2022, worsen the situation by directing spray high into the air, forming a curtain that drivers struggle to see through.

This problem remains in 2025 and is the main limiting factor for safe wet racing, often leading to long safety car periods or even red flags in order to reduce the amount of water standing on track.

In short, even if the car in front can drive safely, the one behind might not be able to react to sudden changes, as seen in the British GP, where Isack Hadjar crashed into the back of Kimi Antonelli when he couldn’t see the Mercedes in front.

Aston Martin of Lance Stroll in spray and rain at 2022 Japanese Grand Prix

A curtain of spray hangs in the air at Suzuka as a line of cars go through

Aston Martin

Aquaplaning risk

While visibility remains the main limiting factor for F1 cars to race under heavy rain, grip is still also an issue, especially when water pools on the surface.

As pointed out above, the current full wet tyres have an incredible capacity to displace water, but those have their limitations.

If standing water accumulates faster than the tread can clear it, the car begins to aquaplane — riding on a layer of water rather than the Tarmac itself.

Once that happens, the driver becomes a passenger. A recent example was Charles Leclerc slamming into the wall at relatively low speed as he was on his way to the grid ahead of the season-opening Australian Grand Prix.

The lightweight nature of F1 cars and the wide tyres make them especially vulnerable to aquaplaning, particularly as the single-seaters have no aids such as anti-lock braking systems or traction control, unlike road cars.

Possible solutions

Over the past two years, the FIA has been developing and testing wheel arches to reduce water spray in heavy rain.

These arches would be fitted over the wheels for only the wettest conditions. It was a pretty simple concept, the idea being to limit how much spray is projected rearward, improving visibility for following cars.

Initial tests took place at Silverstone in 2023 with Mercedes and McLaren cars fitted with prototype arches. A more extensive test followed in mid-2024 by Ferrari, with real-time visibility analysis and feedback from drivers.

However, the results were rather underwhelming. Not only did the arches fail to meaningfully reduce spray, but they also introduced aerodynamic complications.

Leclerc Ferrari wheel arches test

New wheel arches applied just to the rear of Leclerc’s Ferrari

Getty Images

“It was quite similar. So I think back to the drawing board, we need to keep looking at it,” Ollie Bearman said last year after testing at Fiorano.

“The visibility was still pretty tough out there. It was slightly better for sure, the work has gone to something, but not fixed.

“We did four or five runs just trying different levels of openness, because if it (the cover) is fully closed, it’s also quite tough for the temperature of the tyres.”

The FIA hasn’t ruled out future development, but any practical solution will need to balance visibility gains with minimal aerodynamic disruption.

Pirelli has also been testing a new ‘crossover’ compound designed to make the wet tyre more usable when conditions transition between heavy rain and intermediate levels.

However, for now, Formula 1 racing in heavy rain remains an exercise in frustration and safety-first caution.