Kimi Raikkonen, Ferrari, Yas Marina, 2017

“Impossible” to build mule cars to test tyres for new 2026 F1 rules – Pirelli

Formula 1

Posted on

| Written by

Formula 1’s official tyre supplier has warned it will be “impossible” to build mule cars to test the sport’s new rules for 2026.

Pirelli needs to develop a new range for the season after next, when F1 will switch to narrower front and rear wheels. It is part of a drastic overhaul of the technical regulations in which new power units will be introduced and F1 will allow great use of active aerodynamics.

Previously Pirelli has been able to prepare for changes in tyre size using ‘mule cars’ adapted by the teams (pictured above) to simulate the forthcoming new rules. However Pirelli’s motorsport director Mario Isola told RaceFans the nature of F1’s 2026 regulations will largely prevent that.

“It’s impossible, I would say, to create a mule car with similar characteristics,” said Isola. “We will not have smaller cars. We can save some weight – instead of doing long runs with full tanks you can, reduce the level of fuel just to simulate the weight. But for the rest, it’s impossible because you don’t have the active aerodynamics.”

Under the 2026 rules, drivers will be able to switch to a low-downforce mode on straights, then switch back to maximum downforce when cornering.

The 2026 rules will be the third time in 10 years F1 has changed its tyre format. Wider rubber was introduced in 2017, and two years ago F1 switched from 13-inch wheels to 18 inches.

On those occasions teams were able to produce mule cars which approximated the accompanying rules changes. Isola said Pirelli will have to rely heavily on simulation data to develop its 2026 tyres until the first cars arrive at the beginning of the season.

Advert | Become a RaceFans supporter and go ad-free

“This is a similar situation we faced with the mule cars when we were developing the 18-inch tyre, for example, or during 2016 when we were developing the wider tyre for 2017, also in that case we had mule cars that were not fully representative.

2016 and 2017 tyres compared
F1 introduced wider tyres in 2017
“So what is important for us is to work in parallel with the virtual model and the physical model. We try to understand that which is the correlation between the two in order to have tests on-track that are as much as possible representative of what we will find in 2026, knowing that it will never be 100% representative.”

“For the moment, we have simulations that are coming from the FIA, not yet from the teams,” he added. “But in the in the usual process of development we will receive also simulations from the 10 teams and we can understand which is the general idea of the performance estimated for 2026.”

Another change Pirelli has to cope with is the increased electrical power output of the hybrid engines. The FIA estimates total power will increase by around 10% to 1,100bhp. As more of this is being generated electrically, the torque demand on the rear axle is expected to rise significantly.

“We still don’t have numbers for that, we are working to get simulations that are telling us all these numbers,” said Isola. “We need these numbers to characterise the stress on tyres and then design the tyre.”

Pirelli did not join the discussions around F1’s new regulations until October last year, after it agreed an extension to its current tyre supply contract. It pushed against a move to smaller, 16-inch wheels, which the FIA desired to help reduce car weight, as Pirelli feared that would harm car performance too much.

Advert | Become a RaceFans supporter and go ad-free

“The 16-inch tyre that was estimated at the beginning of the process was not the right size, in our opinion, if we want to keep it the performance of the car similar to what we have now,” Isola said.

“If you want to slow down the cars, reduce the loads, reduce the speed, you can go down with the size. But if we want to keep a similar level of performance, we cannot go in this direction, it’s too much. Small tyres like this don’t have the loading capacity that is required for these fast cars and heavy vertical load that you put into the tyres at a high speed.

“We have also the active aerodynamics that is changing the configuration, with the low downforce and the high downforce. So in cornering we have high downforce and you push a lot the tyres on the ground. On the straight, you have lower downforce but much higher speed. That has a different impact on the integrity of the tyre.

“So considering all these elements we came back to the FIA with a proposal of a size that is an 18-inch, slightly smaller, but with the characteristics we believe are guaranteeing that the performance is in line with the expectations.”

He pointed out that the projections of how much downforce cars would create under the new rules changed significantly while the regulations were being crafted.

“In the meanwhile, when we were discussing that, also the estimation changed. So from an initial estimation where the loss of downforce was quite important, we got simulations where the loss of downforce is not so big.

Advert | Become a RaceFans supporter and go ad-free

“So this is another element that we considered and we decided to go with this proposal, knowing that the final target is to have lighter cars to save weight. So we want to do our part in that, but not with a tyre that then is not able to cope with the level of stress that is predicted for 2026.”

Pirelli plans to conduct its first test of the narrower prototype tyres for 2026 in September, with Aston Martin.

Bringing the F1 news from the source

RaceFans strives to bring its readers news directly from the key players in Formula 1. We are able to do this thanks in part to the generous backing of our RaceFans Supporters.

By contributing £1 per month or £12 per year (or the equivalent in other currencies) you can help cover the costs involved in producing original journalism: Travelling, writing, creating, hosting, contacting and developing.

We have been proudly supported by our readers for over 10 years. If you enjoy our independent coverage, please consider becoming a RaceFans Supporter today. As a bonus, all our Supporters can also browse the site ad-free. Sign up or find out more via the links below:

Miss nothing from RaceFans

Get a daily email with all our latest stories - and nothing else. No marketing, no ads. Sign up here:

Formula 1

Browse all Formula 1 articles

Author information

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...

Got a potential story, tip or enquiry? Find out more about RaceFans and contact us here.

15 comments on ““Impossible” to build mule cars to test tyres for new 2026 F1 rules – Pirelli”

  1. What could possibly go wrong?

    1. Just Pirelli, everything else is ok.

  2. bennie johnston
    12th July 2024, 9:18

    I find the artificial requirement around tires so arbitrary… What if instead of tires they chose brake disks. One company to produce them all, teams have to change them during the race to use soft and hard versions, they have to be produced to wear out during the race instead of lasting all the time. Sounds mad! But we just accept it with tires?

    1. ‘We’ accept it with tyres because they are, by far, the most complex part of the car, one of the biggest potential performance levers, and the one most obvious and effective to use to manage and add depth to the on-track competition (being that F1 is entertainment, and – supposedly – a sporting competition that operates on arbitrary sporting rules, as do all sports).

      1. accepting sub-par tires, the worst in all of motorsport for over a decade because ‘show over sport’ is the biggest joke of them all.

        the pinnacle of the sport shouldn’t have to put up with the worst tires, it’s absurd that it’s been so readily put up with because the show has become more important than the sport.

        F1 should be about performance. the tires should be the best available produced for performance and the fact they are intentionally made to be awful just for the show is something that shows how far the show that used to be a sport has fallen.

        and i mean look at all the other nonsense the intentionally designed for the show tires have created with patheticly small operating windows, multiple races of embarrassing problems with for the first time in history regulations needed to hide the deficiencies of the tires with crazy high starting pressures and stuff.

        the whole thing with the tires the past 13 years has just been a pathetic joke thats made the ‘sport’ look like an even bigger joke!

        1. accepting sub-par tires, the worst in all of motorsport for over a decade because ‘show over sport’ is the biggest joke of them all.

          You say “subpar” – but can you actually objectively prove it?
          It’d be great if someone, somewhere, were to provide indisputable evidence that this is actually the case, and not simply a subjective interpretation of what they’d prefer F1 tyres to be like.

          You say “pinnacle” – but that’s not true either. It is objectively equal to the FIA’s other official World Championships in status – and arguably less of a pinnacle than other series such as Indycar, WRC, WEC, Supercars or even Rally Raid (WRRC).

          F1’s aerodynamics, steering and suspensions systems, engines, gearboxes…. None of these are as ‘good’ as they could otherwise be if not constrained by sporting rules. But that’s entirely the point – it’s sporting entertainment, not a pure and unrestricted engineering competition. This is the way F1 has always been, even if you don’t realise or acknowledge it.

          You rant about the tyres F1 uses, but not so much about the physical and scientific limitations of why the tyres are the way they are. These cars are heavy and produce way too much aerodynamic downforce – going this fast means sacrifices must necessarily be made and ‘unwanted’ side-effects will always be present. Tyre design involves a series of compromises, as is the case with pretty much every other part of the car.
          High pressures are a direct result of excessive mass and vertical/lateral loads. Again – this is a car problem, not a tyre problem. Unless you want F1 to use heavy truck tyres, this is what they have to do.
          Could they do without the target letter, or change its content – sure, but F1 would still want a specific set of characteristics in order to make the on-track racing product better, more often, than it would otherwise be.
          It’s a business, after all – and F1’s success is defined financially before any other metric. People not watching because the races are boring is not good for the profit margins.
          No, it’s not ideal that F1 is a ‘money-first’ operation – but the only way for that to not be the case is to go amateur and demonetise the entire series. Everyone in F1 wants money. Lots of it.

          1. You say “subpar” – but can you actually objectively prove it? It’d be great if someone, somewhere, were to provide indisputable evidence that this is actually the case, and not simply a subjective interpretation of what they’d prefer F1 tyres to be like.

            Pirelli has always had a big problem with the operating window of their product. This is a concern going back over a decade now, and you can find plenty of interviews with a series of Pirelli representatives that talk about addressing this in ‘the new compound’. It never happens. We’ve even had prescribed tyre pressures, even mandated pitstop windows and, worst of all, maximum stint lengths.

            They cannot figure it out, and so we have endless tyre nursing exercises. Not to improve durability to any meaningful degree, but to keep them in a tiny temperature window so they don’t lose all grip which leads to more sliding, which leads to more wear, etc. And still F1 races are usually seconds off the pace compared to qualifying. Everyone has to tip toe around because this problem only gets worse the softer the tyre is, so it’s never viable to use softer tyres and make extra pitstops compared to the competition.

            Yes, their brief is complex. Making half a dozen compounds that need to have different performance characteristics but – in the grand scheme of things – very similar durability is a huge challenge. But it’s also something Pirelli willingly signs up for, and even uses as a plus in their (so far successful) attempts to keep the F1 contract – contrary to other manufacturers which have openly stated they refuse to make such tyres.

          2. Pirelli has always had a big problem with the operating window of their product.

            Actually, F1 teams have had (or created) the problem with the operating window – not Pirelli.
            The teams build, setup and operate the cars the tyres are supplied for – they are the ones who need to compromise and adapt to the tyres they are given.

            We’ve even had prescribed tyre pressures, even mandated pitstop windows and, worst of all, maximum stint lengths.

            Every professional circuit racing series has prescribed minimum tyre pressures. Many series use pitstop windows or other comparable means of forcing competitors to take pitstops (such as refuelling and/or mandatory driver changes, inducing pitstops anyway). So did F1 in the past.
            The one time F1 have mandated maximum stint lengths was great – the drivers hadn’t had the opportunity to drive the cars that hard for that long for decades, and haven’t at any event since. They actually looked like they’d been in a sporting contest for once, rather than a relaxing Sunday drive in the countryside.

            Not to improve durability to any meaningful degree, but to keep them in a tiny temperature window so they don’t lose all grip which leads to more sliding

            Teams choose to create car designs, aero loads and suspension geometry which warm the tyre up quickly, and ultimately enable them to overheat very easily. This is not specific to any particular type of tyre or manufacturer.
            Driving slower (5+ seconds per lap off potential race pace) enables the tyres to last longer, which costs them less time loss in pitstops and opens up strategic options later in the race – durability is exactly the name of the game with this temperature management.
            It’s very much about playing it safe rather than taking any strategic or competitive risks.

            But it’s also something Pirelli willingly signs up for, and even uses as a plus in their (so far successful) attempts to keep the F1 contract – contrary to other manufacturers which have openly stated they refuse to make such tyres.

            Hankook did make a proposal under the current target letter conditions – but F1 chose to keep Pirelli.
            As much as the teams may complain about the tyres, they know that if someone else has a go at it, they could (and likely would) be much ‘worse.’
            F1 teams fear a repeat of the opening of 2012…

            Other tyre manufacturers are unwilling to make F1 tyres they can’t fully control, and that would likely attract negative media and opinions from people who don’t really understand it all. Who can blame them?
            But the other side of that coin is that F1 knows they can’t let go of (target letter) control of the kinds of tyres they use – they need the on-track product to be a certain way to maintain their audience. They also know they can change the technical regs if they want to make their tyre demands much more easy to achieve – but there are simply too many fat fingers in F1’s financial pie to upset anyone by doing so.

  3. I’m sure Michelin or Bridgestone would have found a way. Could have have Brad Pitt driving it.

  4. I think they will get it right in their 16th attempt…

  5. I believe Andretti has a 2026 spec car Pirelli might be able to test.

    1. I believe Andretti has a 2026 spec car Pirelli might be able to test.

      :)
      but I think Pirelli would expect it to move under its own power, so that’s a non-starter

  6. People can fly drones on Mars but Pirelli can’t make a proper test car for their F1 tyres. Just typical.

    These tyres are awful, and while some may say that Pirelli was asked to make high degradation tyres, that still doesn’t explain away the dozens of other issues they’ve had over the years and continue to have to this day.

    While their road tyres usually score well and come fitted with some pretty impressive cars, whenever I’m looking for tyres the Pirelli filter always gets turned off instantly along with all the budget tyres that, frankly, shouldn’t even be allowed to be sold.

  7. Maybe next year they could do away with the requirement to run two different compounds in a race, and maybe we’ll get cars which are a bit slower, but lighter on the tyres and can run a race in two stops, versus a faster car needing three stops. With the current rules, Pirelli want to make tyres where everyone can run the whole race with just the single mandatory stop, and everyone runs pretty well the same strategy, which sort of defeats the point of the rule.

  8. Coventry Climax
    14th July 2024, 12:40

    Previously Pirelli has been able to prepare for changes in tyre size using ‘mule cars’

    You’re kidding, right?

    “For the moment, we have simulations that are coming from the FIA, not yet from the teams,”

    Meaning in all these years, Pirelli have not spent a dime on creating their own simulation.

Comments are closed.