Safety Car, Interlagos, 2024

Why F1’s 2026 cars should be better suited to racing in the rain

Formula 1

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When Formula 1 abandoned efforts to hold qualifying for its grand prix on Saturday afternoon at Sao Paulo, Lewis Hamilton decided to make a point to the series’ CEO, Stefano Domenicali.

“You should have sent us out,” the seven-times world champion chided the Liberty Media chief. “It’s ridiculous, we should go out. I want to go out. If you give us better wet tyres and [tyre] blankets, we’ll be able to run in this.”

F1 drivers have criticised the performance of the series’ wet weather tyres for years, specifically the full wet weather tyre used when conditions are at their worst. But Hamilton’s criticism only addressed part of the reason why the session had to be delayed until the following day.

“The decision was taken not to proceed with qualifying due to poor visibility, standing water on the track and fading light,” said the FIA and F1 in a joint statement on Saturday afternoon. Visibility – not tyre performance – was the overriding concern.

Along with the postponement of qualifying, the FIA and FOM took a decision which is virtually unprecedented in modern F1: They moved the start time of the race forward. We have seen races delayed for rain many times, but proactively bringing a start forward to avoid an anticipated downpour was a rare move, and the correct one. It showed a lesson was learned from the farcical 2021 Belgian Grand Prix.

But the key problem remains that current F1 cars do not race well in the rain. Aquaplaning in deep water is part of the problem, but so is the plumes of spray thrown up by each passing car which make visibility progressively worse for each that passes by. This has always been a problem, but it has worsened in recent years, for two reasons.

First, F1 introduced wider tyres in 2017. This was a significant change: The front and rear wheels became almost 25% wider. The total tyre width for a single F1 car rose from 1,140mm to 1,420mm. With more treaded rubber on the track’s surface, the volume of water being lifted into each car therefore increased.

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The second significant change came in 2022, when F1 overhauled its technical regulations giving teams greater freedom to use the flow of air beneath their cars to generate downforce. But a consequence of this is the larger ‘tunnels’ and diffusers draw up even more water from the track surface and fling it into the air behind as they pass.

This is partly why the FIA’s attempt to address F1’s wet weather visibility problem using wheel covers – dubbed ‘mudguards’ by some on account of their appearance’ – proved unsuccessful in real-world tests.

However F1’s next revision of its technical regulations promises to make a step forward in both respects. Tyre widths will be reduced, albeit not to 2016 widths, and the cars’ floor will be simplified.

Pirelli motorsport director Mario Isola expects the changes to the floor will have a significant impact. “The new cars will be completely different [on] the floor,” he told RaceFans earlier this year.

“At the moment, it is true that a lot of water spray is coming from the tyres. But it’s also true that a lot of water spray is coming from the diffuser. When they tested these ‘mudguards’ on the tyres it was clear that a lot of water and therefore lack of visibility is coming from the water spray coming from the diffuser.

“So we will consider the spray coming from the narrower tyre. I cannot imagine that [will be] completely different to what we have now, but the floor and the mechanism to generate downforce for the new 2026 tyres will be different.”

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How much of a difference each change will make remains to be seen. F1’s 2026 tyres will still be wider than those used 10 years earlier. And the downforce cut originally envisaged under the next generation of rules has been scaled back.

But however modest the change proves to be, if it helps avoid the kind of disruption that occured last weekend, it will be welcome.

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Keith Collantine
Lifelong motor sport fan Keith set up RaceFans in 2005 - when it was originally called F1 Fanatic. Having previously worked as a motoring...

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28 comments on “Why F1’s 2026 cars should be better suited to racing in the rain”

  1. Next to tires and floor design, a vast number of drivers would do good to train more in the wet as well, as there was quite some skill level difference demonstrated in Brasil.

  2. Even Isola acknowledges that these changes won’t make a significant difference.
    The cars are too big and wide and they make way too much downforce from under the car. Dialling back 5-10% of the spray won’t make a difference to whether or not the conditions are deemed suitable for racing.
    They need 50%, at least.

  3. The front and rear wheels became almost 25% wider. The total tyre width for a single F1 car rose from 1,140mm to 1,420mm. With more treaded rubber on the track’s surface, the volume of water being lifted into each car therefore increased.

    I believe most of the drivers (except couple of newbies) were complaining about aquaplaning, not poor visibility. With narrower tyres aquaplaning will become even more of a problem because they won’t be able to remove as much water from the contact patch as before.

    1. But with Narrow tyres you have also that the tyre cuts through the water so it will be a balance between contact patch vs cutting the pools.
      Also it’s not the tyres which is the cause of aquaplaning but the height of the floor. If the water hit the floor the car is lifted and causing aquaplaning that way.
      It’s clear they have to do something about the diffusers if they want to improve racing in the wet.

    2. It’s actually the other way around: the bigger the tyre surface, the bigger the aquaplaning risk.

      1. It’s actually the other way around: the bigger the tyre surface, the bigger the aquaplaning risk.

        I think that element* rather depends on the tyre tread design – which brings Pirelli right back into the frame.

        *Another part of the equation will be non-compressible (or much less so) water in a narrow slot under the car floor disrupting the normal flow.

        1. notagrumpyfan
          7th November 2024, 11:29

          I think that element* rather depends on the tyre tread design

          It’s primarily the width, which even the best thread designs cannot overcome.
          You never hear cyclists complain about aquaplaning even if the thread is totally gone ;)

          1. notagrumpyfan
            7th November 2024, 11:33

            *tread

          2. i have aquaplaned on a motorcycle, it’s the tires ability to move water away that is important. go fast enough, through enough water, aquaplaning is always possible. its a volume per unit of time problem.

      2. Indeed, narrow tyres are less at risk of aquaplaning. Especially with Intermediate type tyres, which have a very basic pattern. They’re made to be a close to slicks as possible while still retaining some wet surface viability. The displacement is quite limited.

      3. ever aquaplaned on a motorcycle ? its more than surface area, its the way the water flows around the tire, the weight, etc… aquaplaning on a bike is nuts btw.

      4. James Coulee, it would appear to be the slenderness ratio of the tyre’s contact patch that contributes towards aquaplaning risk, with aquaplaning being less likely to occur when the contact patch has a higher slenderness ratio (i.e. where the contact patch is relatively long compared to it’s width). Two tyres could have a similar sized contact patch, but if one had a contact patch that was more slender than another, then the one with the more slender contact patch would be less prone to aquaplaning.

    3. I believe most of the drivers (except couple of newbies) were complaining about aquaplaning, not poor visibility.

      Fact based statements will get you nowhere. You see that doesn’t fit with the “Pirelli aren’t the guilty party, it’s the teams’ car designs” narrative, does it?
      Carrying on with that line will get as far as complaining that the “sprint” Mickey Mouse things shouldn’t exist.

      1. Except there were no facts to be found, just a complete misunderstanding of how tyres work.

      2. The fact is that the current cars are indisputably a huge part of the problem, and therefore, also an equal part of the solution (if F1 ever wished to actually find the solution, which it doesn’t).
        Pirelli are certainly no more guilty than the teams who design, engineer and operate the cars in specific ways and the technical regulations the cars are created to.

        Sometimes facts are the narrative, simply because they are the facts.

    4. notagrumpyfan
      7th November 2024, 9:00

      With narrower tyres aquaplaning will become even more of a problem because they won’t be able to remove as much water from the contact patch as before.

      It’s quite the opposite!
      I’ve got a 2CV back in Europe, and on pouring days that car gives me the most planted feeling (thin tyres, and just enough power the conditions can handle).

      1. I can attest to this too. My Citroen 2CV was not affected by floods at all, thanks to its ‘chunky’ 12cm wide Michelin radials. Then again, maybe that was thanks to Michelin rather than their narrowness – no doubt both are big factors.

    5. You don’t need to move more water if the contact patch is smaller. Quite the contrary. Slimmer tyres are better for avoiding aquaplaining.

  4. I think intermediate tyres will always be the best compromise, simply because they can react well enough to various weather conditions from dry-ish to very wet. Wet and dry tyres have a much narrower window, and putting either in changeable conditions only to find it’s the wrong tyres is a +20 second loss instantly.

    Even if the wet weather tyre was much more competitive, teams would hesitate on changing their inters for them.

    1. Yes!
      And it’s the main reason that the majority of racing series now don’t use (or allow) an intermediate (or hand-cut) tyre – they have slicks and wets, and nothing in between.
      Saves money, reduces environmental waste, saves hassles and arguments – and ultimately improves the on-track product.
      Wins all round.

    2. In 2016 they didn’t, simply because the tyres were closer and they allowed more racing in wet conditions.

  5. Looking at the number of spins and crashes that occurred in previous eras then it looks like the current generation of cars are perfectly fine in the wet – some wet races in the last few years have had little or none of track excursions.

    1. One thing I’ve been reminded of, courtesy of the F1 YouTube channel posting race highlights from previous years at the upcoming track on the schedule, is how much of a high-attrition circus the races could be, even in the dry, let alone the wet. I’ve been watching since 2000, and of course I recall heroic wet weather drives to glory, but I’d forgotten how many cars had rather more ignominious results in the wet

  6. Sergey Martyn
    7th November 2024, 10:29

    Just give ’em bicycle wheels for rainy days!

    1. notagrumpyfan
      7th November 2024, 11:08

      plus training wheels for Stroll ;)

      1. I’d give him a two-seater with a good driver and the condition he isn’t allowed to navigate.

  7. Given the same tread designs, a narrower tire shoiuld displace as much water AS A RATIO OF ITS TREAD PATCH, as a wider tire. Wider tire, bigger tire patch, narrower tire, smaller tread patch.

  8. Trevor Knowles
    7th November 2024, 23:25

    Often, when they are aquaplaning, it’s the plank that’s holding the car off the ground by being sat on the water rather than the tyres.

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