F1
F1 car wheel arches tested by Ferrari to combat wet race spray
Wheel arches could be fitted to F1 cars in an effort to reduce the vast plumes of spray that limit visibility in wet races
Why can't F1 cars race in heavy rain? The reasons we rarely see full wet tyres
F1
- Last updated: October 4th 2026
Heavy rain still stops grands prix, and F1's 2026 cars have yet to show they're any better in it. But that's not necessarily Pirelli's fault...
Rain stopped racing in the 2025 Belgian GP
Grand Prix Photo
Formula 1 cars are among the most technologically advanced machines on the planet, with materials, software and performance that have more in common with a fighter jet than a road car. But for the last few years they’ve had one embarrassing limitation: they can’t really race in the rain.
Grip hasn’t been the problem – visibility was. The vast clouds of spray F1 cars generated in the rain meant that drivers – with the exception of the leader – were racing blind: Isack Hadjar ran into the back of Kimi Antonelli at the 2025 British Grand Prix because he couldn’t see the Mercedes ahead.
While years ago, drivers would have been left to race regardless, modern racing has less appetite for risk, and so drivers are often left waiting in the pitlane for the weather to clear: rain delayed last year’s Belgian Grand Prix was delayed by 80 minutes, and it then started under the safety car.
The ground effect problem
The problem was exacerbated by the last generation of F1 cars, which raced between 2022 and 2025. They made extensive use of ground effect, where a high-speed stream of air under the cars sucked them to the ground. On a wet track, that airflow picked up water droplets on track, carried them to the back of the car then hurled those droplets upwards, where they joined the water churned up by the tyres, creating a dense cloud of spray.
What’s more, an ultra-low ride height (necessary for maximum ground effect) meant that the cars were also susceptible to high-speed aquaplaning. The lowest part of the car, known as the plank, regularly scraped on the track surface, as seen by the shower of sparks from underneath in dry conditions. In wet weather, it could easily make contact with puddles on the track, which caused the car to float, and the driver to lose control. This happened to Charles Leclerc in Australia in 2025 when he slid into the wall at relatively low speed on his way to the grid.
Are 2026 cars be better at racing in the rain?
Fast-forward to 2026 and some aspects should, in theory, be better. The new cars are narrower and have less ground effect, so on paper they should throw up less spray – but nobody really knows because we have not had a wet race yet.
However, the extra electrical power in this year’s cars – which provides an instant, powerful burst of torque – could make the cars unpredictable, and a real handful. Ahead of the Miami GP, where rain was forecast but didn’t materialise, drivers spoke of rain being a “real challenge” and potentially causing “a bit more chaos”, according to Lando Norris.
With the Malaysian GP set to feature rain (as Sepang often does), we may be about to find out whether they should have been worried or not.
Intermediate tyres (left) have shallower grooves than the blue-sidewalled full-wets
Red Bull
The tyres
Formula 1 uses two types of tyre in wet-weather conditions: intermediates, with a green stripe on the sidewalls, have shallower grooves for damp or drying tracks and flex to generate heat on cooler surfaces where slicks would struggle.
However Kimi Antonelli, who drove his Mercedes in a wet pre-season shakedown at Silverstone, said the intermediate tyres struggle to build temperature, so when there is standing water, the the full wet tyre becomes the obvious choice immediately.
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These blue-striped full wets have deeper grooves to clear standing water. On the 18in wheels used until 2025, they shifted over 85 litres of water per second at 186mph (300km/h).
In 2026 the wheels are narrower by 25mm at the front and 30mm at the rear which should mean that they produce less spray, but they still clear the equivalent of a bath of water with every revolution. We’ll need to wait for a wet grand prix to see if visibility improves.
If the spray becomes less of an issue then the limiting factor for the wet tyres will be the intensity of the rain: when standing water accumulates faster than the tread can clear it then the car will aquaplane; the tyres riding on a layer of water rather than the asphalt itself. At which point the driver becomes a passenger.
Increased, often unpredictable, power
With the reduction in ground effect this year, there should be better visibility. However, the drivers are concerned about these new cars’ behaviour in the wet. “Definitely it was very tricky,” said Kimi Antonelli of his pre-season Mercedes shakedown in the rain at Silverstone.
The bigger unknown is the power delivery which, in 2026, is split roughly 50-50 between the car’s combustion engine and its electric motors. The limited electrical power is deployed over the course of the lap in sections where it is most effective – as determined by an algorithm.
Contemplating a wet Miami GP earlier this year, Oscar Piastri outlined the issue: “It’s just going to be what happens with the power-unit, how you get power, where you get power is in a computer’s hands.
“Just making sure that that does roughly what we expect. Obviously, the margin for error when it’s wet is significantly smaller.”
Some rule changes were made in anticipation of difficult conditions, with use of the boost button outlawed in low grip conditions like rain. This mode allows drivers to override the algorithm and trigger an instant power increase – usually to overtake or defend.
Rain will also alter use of straightline mode, where sections of the front and rear wings flap open on straights to reduce drag and increase speed. In wet conditions, the rear flap will be deactivated, reducing maximum speeds and increasing downforce for better grip. If race officials deem conditions severe enough, the front wing flaps will also be deactivated.
Can anything else be done?
The FIA has tried wheel arches in the past, which would be fitted when a race is red-flagged for rain so it can restart sooner. Mercedes and McLaren cars ran prototype arches at Silverstone in 2023, and Ferrari did a more extensive test in mid-2024 with real-time visibility analysis and driver feedback.
The arches didn’t improve visibility enough, they did nothing about the spray from ground effect, and they brought aerodynamic complications of their own. Ollie Bearman, after running them at Fiorano, said it was “back to the drawing board”. Closing them up completely, he added, mades it tough to keep temperature in the tyres.
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