George Russell, Mercedes, Yas Marina, 2020

New 18-inch tyres will make F1 cars up to two seconds slower – Allison

2020 F1 season

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Formula 1’s new 18-inch tyres will be a step backwards for car performance but could make the competition closer, Mercedes technical director James Allison says.

The move to 18-inch rubber was originally due to happen in the 2021 F1 season. However the postponement of new technical rules due to the pandemic means the change will not happen until 2022.

That means the current 13-inch wheels will remain for another year. Allison says these are a superior technical solution to the format which will replace them.

“All things being equal the bigger rims, low-profile rubber is always going to be a worse tyre than the sort of tyres that we have on our racing car today,” he said in a video published by Mercedes.

“That sort of balloon-type tyre that you see on our cars today and have seen on racing cars for decades is a really good solution for going quickly. It allows the tyre to transmit the forces to the road really effectively, it’s light, it acts as a good suspending element so it gives the driver good ride quality, allows the forces to be taken at quite low inflation pressures, which means you get more grip, et cetera.

Pirelli's prototype 18-inch 2021 tyres
Pirelli’s prototype 18-inch tyres
“So from a lap time point of view the way we currently do it is definitely the right way. And the new tyres are going to be heavier, lower grip and worse for ride – all other things being equal. So they’re going to slow the cars down by somewhere between a second and two seconds, something like that.

“Of course Pirelli are putting a lot of effort into to mitigate those losses and to bring an improved technology on the low-profile tyres. That means that they will still be good racing tyres. But all things being equal that sort of tyre is not a good thing.”

Allison said he isn’t convinced by some of the arguments for introducing the new tyres. “I guess if you are a 13-year-old boy or a fan of ‘Fast and Furious’ films you’d like the look of the tyre,” he said. “So aesthetically they appeal to some people.”

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While 13-inch wheels have largely fallen out of use on road cars, Allison believes following the car industry trend for larger wheels makes sense.

Mick Schumacher, Prema, Bahrain International Circuit, 2020
Formula 2 will race on 18-inch rubber this year
“For road cars, where performance is not at such a premium and economics are much more important, that is a better overall way to make a tyre from the point of view of the whole package that is presented to the consumer. And so aligning our world better with the road car world means it’s probably more relevant, what we are doing, to the road cars. That’s important.

“It’s also important because it means that time manufacturers are inherently more interested in being part of Formula 1, which is an important part of our sport, making sure that we have strong and committed time partners.”

The sport’s governing body and commercial rights holder also believe the new tyres will increase competition between teams, said Allison.

“Everyone who designs cars knows that the aerodynamics of the tyres is really important. The way in which the car interacts with the tyre as it changes its shape as it’s squashed and distorted by driving around the track, that makes a lot of difference to the aerodynamics.

“So understanding how to design a car to work well with that moving target of a tyre that’s always changing shape is tricky. And it’s one of the many things that distinguishes the front of the grid from the back of the grid: How good a handle you have on that particular geometrical problem.

“If you have a lower-profile tyre because there’s less tyre and that tyre is more rigid in its sidewall, it moves less. And so it presents less of a dilemma to the car designer.

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“So if you were in the FIA and FOM and wanting the grid to compress up, there’d be more of a catfight from front to back, having tyres that don’t interfere so much with the aero is a good thing from our point of view. And they hope that that will compress the grid.”

James Allison, Mercedes, Interlagos, 2019
Allison sees the new tyres as “an opportunity”
However Allison says Mercedes hope to take advantage of the introduction of new tyres to increase their advantage over their rivals.

“If you’re in a team, you could look at this challenge that is being put in front of us of a completely new geometrical shape, a completely new set of design constraints, and you’d think ‘alright, tear up everything we know and the prizes are going to go to the team adapts best and quickest to the new challenge of the new tyres’.

“So for us, this new tyre is an opportunity. Yes, it’s going to make the car go slower. Yes, it doesn’t appeal to me visually. But it’s a big opportunity to see whether we can use it to actually, far from compressing the grid, to stretch our heels.

“So with a bit of luck we will work well and better than our competitors. But I guess time will tell whether that plays out or not.”

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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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44 comments on “New 18-inch tyres will make F1 cars up to two seconds slower – Allison”

  1. I have an opinion
    4th June 2020, 12:51

    Hopefully this Formula One engineer’s statement has put to bed the argument that large wheels on road cars exist for any reason but looks.

    1. Off course it is for looks. Although larger tyres also can put more force on the road through larger contact patch. That is why the F1 cars have far larger rear tyres than they have front tyres

    2. Well, no, because that isn’t what he said. Road cars aren’t only looking at ultimate performance.

      Obviously where two tyre and wheel combos have the same diameter, but one has more tyre and one more rim, that’s more to do with looks. But there’s been a trend towards much larger overall diameters, so looks aren’t the whole story.

      Iirc, other things being equal a larger-diameter wheel has lower rolling resistance. There are other similar factors, I’m sure.

      Economically, it tends to be a bit cheaper to buy a lower profile tyre than one with the same diameter and width but taller sidewalls.

      1. Going from 15 inch to 16 inch tyres when buying a new sub 20k car is usually a 1000€ option.

    3. John Martin
      4th June 2020, 15:23

      Road cars tended to go to bigger wheels to fit larger brakes, as wells as for the aesthetics to balance out the generally bulkier and bulbous designs that have resulted over time from crash testing needs, aerodynamics, etc. F1 cars have enough braking power from carbon brakes that larger wheels were never needed, I believe.

    4. Not directly related. Road car tyres don’t affect aero that much if at all, and the suspension on road cars are not that rigid that, quite squishy actually, so a rigid tyre will help road cars. A bunch of videos online compares bigger wheels and tyres to stock, where they did perform better. There is a point though where wheel and tyres can be too large and the car does indeed go slower.

    5. F1oSaurus (@)
      5th June 2020, 9:16

      Road cars started adopting larger rims only after racing cars were using bigger and bigger rims. So there must be some performance benefits. At least for touring car racing.

    6. Not what he is saying and the cars are (obviously) not the same. Same car with say 255/35/19 will out perform 255/65/19 in bends and acceleration.

      But yes looks come into it as usually ride comfort can be compromised.

      F1 is totally a different beast. The 18″ rims are not changing the overall size of the wheel that much so everything being said to down to the tyre dimensions which is not quite the same as going bigger on car wheels.

  2. So he basically did a Horner but in a much smarter way and used the opportunty to say the new tyres will make the cars slower, uglier and further apart.

    1. @minilemm ‘Did a Horner’ heh. Yeah I suppose he did, but behind Allison’s perma-smile, he can also be quite harsh like shown here.

  3. Interestingly tyre suppliers have always held the view they offer more performance.

    I know that Michelin ran a test on a world series by Renault car & found that the 18″ wheels were upto a second a lap faster with minimal changes to the suspension. And it was felt they could have got more performance out of them with a car specifically designed around 18″ rims.

    1. it IS interesting, isn’t it. Maybe for the specific case of F1, it makes sense when they shove a large part of what the suspension does onto the tires? Since they know relatively much about how it behaves by now, they are able to finetune the suspension around that?

      I always understood that performance cars have the larger wheels, with relatively skimpy tyres both to have a stable platform with not too much uncontrolle flexing and have large contact patch and the better rolling performance of the larger tyres.

    2. @gt-racer
      This surprises me greatly. With some common sense, you can see that all other things being equal, the 18 inch rims with tyres will have a higher metal to air ratio than 13 inch rims. This means that they will be far heavier than 13 inch rims (and this is unsprung weight so more of an effect on performance), with the upside that the lower amount of air means less air to heat, so tyres will come up to temperature quicker. Could have an effect on your first flying lap if tyre warmers are not being used, but after that it is unlikely to make any difference.

      Other effects will include less “suspension” travel (the tyre compressing makes up a significant amount of the suspension travel of a F1 car), so the cars suspension will likely need to be made slightly softer to compensate.

      All of that makes the claim of a second a lap faster hard to comprehend, unless they were talking about the first flying lap without tyre warmers, in which case its possible but I would still have thought unlikely. (GT racer I believe you btw – I saw the article too – just a comment on michelins claim!)

    3. @gt-racer as I understand things, one of the people who attended the event where Michelin announced the switch to the larger rim wheels for Formula Renault did raise a number of questions about the lack of transparency by Michelin on how those tests were carried out.

      It was reported that, when Michelin allowed some reporters to try cars which were fitted with 18 inch wheels, they did not allow them to carry out back to back comparisons against the standard smaller rims – they were only allowed to try the larger rims.

      It was also reported that Michelin refused to provide any information about the track conditions during those tests (i.e. track temperatures, how rubbered in the track was etc.), what tyre compounds and fuel loads had been used in those tests or the drivers involved – they just announced that they were faster, but provided no context on how those results were obtained.

      Now, it may well be that they were quicker in that situation, but the heavy stage managing of the event and the lack of information presented by Michelin, coupled to multiple references to the aesthetic qualities of the larger rims in the official press release, made some wonder whether there might have been some selective cherry picking of the results by Michelin to justify the larger rims.

    4. F1oSaurus (@)
      5th June 2020, 9:18

      @gt-racer exactly. It’s only because racing cars started using bigger and bigger rims that people started putting those on their road cars also.

      It makes no sense that other race teams were just sporting these bigger rims for looks.

  4. I just think it’s an another example of a poorly considered decision that is more about selling tyres than it’s relevance to F1 as a sport. The tyres are heavier and more difficult to manoeuvre and I don’t think they are especially attractive either. They will also create a problem for teams to work with. So I ask why do this at all?

    1. Not sure why they are going to be a problem for the teams to work with. Since they (F1) are the last entity in the world, be it in racing or on domestic cars, to use balloon tires, does that mean everyone else has it wrong then and are having difficulty dealing with low profile tires? I think not.

      1. I meant literally heavier for things like changing them in pit-stops and more difficult for teams to work with in aero design. This is what James says in the article, more or less…not me. I am sure they are all capable of making designs work but my point, obviously, is why bother.

      2. @robbie on an international scale, I believe that 13 inch rims are actually still a more common format than 18 inch rims – 18 inch rims and lower profile tyres are more common in richer nations, but outside of those markets, you’ll find that higher profile tyres and smaller rims are still quite a bit more common than you think.

        In at least some series, the use of low profile tyres has effectively been mandated by the way that the regulations have been written. For example, if you look at the World Endurance Championship, traditionally the regulations for the LMP1 category were written in such a way that the only way to fit the maximum sized brake disc to maximise the braking performance of the cars was to use large rims with low profile tyres (the latter a necessity from the restriction on total wheel diameter): in the LMP2 category, the use of large diameter rims and low profile tyres is explicitly mandated in the regulations.

        1. Anecdata, but 13″ rims are very small indeed. Not fitted as stock on anything bigger than a microcar in 20 years or more, AFAIK.

          Poorer countries tend to import a lot of used tyres, so to some extent they have to use what we’re discarding. (A car on mismatched snow tyres in the Caribbean makes, er, interesting noises cornering! Lots of grip, not great tyre life…)

          “the only way to fit the maximum sized brake disc to maximise the braking performance of the cars was to use large rims with low profile tyres ”

          Inboard brakes?

          1. If we’re going for road relevance, 15 or 16 inch would make more sense than 18 inch

          2. Dave, at the front of the car, at least, there were a number of problems, particularly with integrating inboard brakes around the front crash structures and also on the locations where you would be permitted to create openings in the bodywork for ventilation – whilst in principle you could put them inboard, if I recall well, you’d probably be unable to cool them properly because you wouldn’t be allowed to place ducts in the bodywork in that region. The upcoming Hypercar regulations, meanwhile, make it mandatory to have an outboard position for the brakes.

      3. Drag racers use balloon tyres because of the high performance they provide.

  5. DAllein (@)
    4th June 2020, 15:14

    I guess if you are a 13-year-old boy or a fan of ‘Fast and Furious’ films you’d like the look of the tyre

    Brilliantly said!
    Totally highlights the stupidity of 18inch tyres!

  6. “It’s also important because it means that time manufacturers are inherently more interested in being part of Formula 1, which is an important part of our sport, making sure that we have strong and committed time partners.

    …soo, they’re working with Gallifrey ?

  7. tony mansell
    4th June 2020, 17:52

    Presumably Mercedes would veto them if they didn’t think they would have an advantage?

  8. What a load of bull. Other racing series do just fine on larger rims.

    F1 had 13 for years to limit braking power. For long time braking is good enough.

    1. So, you know more than the Mercedes technical director? You are obviously in the wrong vocation ….

  9. David (@davidtyrrellf1)
    4th June 2020, 20:12

    I’m sure a lot of fans wouldn’t care if the cars were 7 seconds slower if the grid was closer and more competitive.

  10. I say BS to this article. Larger rims means less movement of the tire under load, that can never be a bad thing.

    1. I don’t know, do you think current suspension systems are as responsive and dynamic as the mechanical properties of a tyre? I don’t know. the new tyre do have a bigger footprint but if Allison does not like them it is probably because the change goes against the work merc has put in.

    2. Larger rims = a lot more weight

    3. Your credentials are?

  11. Allison loves to explain f1. I don’t know if I believe that this change might be a way for mercedes to be even better as from what he is saying, mastering the current tyre is a big componet of their current success. Perhaps suspension wise merc might come up with another ultra sophisticated passive system and claim supremacy nonetheless.
    From the side the massive wheel makes the car look shorter that said from the front it makes the car look narrower, since 2010 f1 cars look very long and narrow.

  12. I was surprised when I saw the clip where Allison talks about this. He didn’t even mention changes to the suspension to compensate for the loss of tire-flex with a smaller sidewall. That to me must be a huge advantage over the balloon tires as it puts the control of the suspension movement in the hands of the engineers rather than the tire manufacturer. Allison is a much smarter man than me, but I can only think he actually underestimates how well his team will adapt to the new tires given just a bit of time. Or is he downplaying things so that the other teams will think they are alright while in fact they need to get their cars two seconds faster to keep up with what Merc has in store…

    1. James Smith
      5th June 2020, 6:56

      He probably thought it was too obvious to mention that suspension movement is deliberately restricted to keep a stable aero platform. Rigid suspension requires flex in the tyres to do the job of the suspension, ie compliance over bumps, etc. They’ll lose that with 18″ tyres, so they’ll have to make the suspension softer, which will give a less stable aero platform that will make the cars slower.

      1. Why would it be a less stable aero platform when the suspension travel is in the form of springs, dampers or hydraulics rather than the tire rubber flexing uncontrollably? Both would affect ride-height just as much, but the suspension can be adjusted while the tire can’t, especially with tightly restricted tire pressures.

        1. the suspension parts are placed where they least interfere with the airflow to the sidepod inlets, barge board area, diffusor, etc
          a suspension that moves and changes angle more interferes more

  13. I fear this constant clamour for road relevance will end up killing the sport. All the innovations that motorsport gave to road cars were a result of competitors pushing technological boundaries, the result of sport, not of trying to emulate road-conditions or technology. Motorsports’ innovations over the years have been the byproduct of doing almost the complete opposite of pandering to the road industry.

    F1 is not the forum for solving the problems of the road industry. If innovations do come from the world of motorsport (a) they will do so as a result of innovators thinking in terms of competition and (b) they will likely come from series that are inherently road-like ie. sportscars, as most innovations have done in the past (if they didn’t originate in space exploration or aviation). F1 must remain a sport for engineers as much as drivers because without that heat of technical competition it is just a contrived soap opera that offers less excitement than your local kart league.

    1. F1oSaurus (@)
      5th June 2020, 9:29

      @frood19 Bigger rims is an innovation that came from racing cars. The reason that lower profile “look more sporty” is because they got used on road car racing.

  14. To solve this issue of deciding which is better between big and small rims, why not allow multiple tyre manufacturers trying different things.
    I would love seeing Michelin, Pirelli and Bridgestone supllying teams with 13, 15 and 18 inch wheels and see which ends up fastest.
    But given how we’re moving to a spec series, we will never know.

  15. In reference to the move to larger wheel diameter – it’s a double-edged sword.
    On one hand, they’ll be gaining much more control over the suspension movement and reducing losses in sidewall and tread flex and distortion that those factors alone would give the potential for faster lap speed and greater consistency through the tyre life.
    On the other hand, they’ll be battling with vastly increased fast bump loads shooting through the suspension and chassis, so the drivers will need to be much more careful to avoid ripple strips and speed bumps. The increased accuracy of tracking and controlling suspension movement will be offset by learning how to use an entirely different system to what they’ve had previously – and indeed what F1 has been designed around for decades. Turn in will be sharper, reaction time will be shorter and tyre wear will be different with far smaller sidewalls.

    Some teams and drivers will get it quickly, others will struggle for some time.
    Hopefully will can have something resembling the first half of 2012 again for atleast a little while.

  16. By the time these wheels/tyres come into racing (presumably 2022), I’m sure teams and engineers will have designed around them in such a way that the cars are either not slower, or only a little slower to start and by mid-season faster. This is true for many, many regulation changes.

    If people want to make a fuss or complain for various reasons, by all means. But this one potential point, imo, is not important.

  17. Kristian Sørensen
    20th February 2021, 1:24

    Well.. a couple of points:

    1) Are the rims really heavier than the tire? Asking as many sports car brands make the rims out of ultralight carbonfiber. Hence going from 13 to 18″ might actually reduce the weight of the wheels. Add to this less tire flex, and I can atleast partly understand Michelin’s claim.

    2) With less rubber between the rim and the road, suspension will have to be redesigned with more travel. Will this result in extra weight, or can it be done with no weight gain?

    I think these are important things to consider in regards to how performance with the 18″ tires will end up.

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