Formula One

F1 Tyres Explained – The compounds, the rules, the supplier and more

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Photo by XPB / Icon Sport

Tyres have been a very important factor in determining the results of Grands Prix for many years, and the current era of Formula 1 is no different. The rules and compounds may be complicated for some, but understanding them is key to understand how a race unfolds.

The supplier

Since 2011, Pirelli have been the sole supplier of tyres for the Formula 1 teams. The Italian manufacturer returned to the sport after a twenty-year absence, taking over the reigns from Bridgestone. The championship has featured a single supplier from 2007 onwards and is chosen by FIA, which differs from the past, when we often saw tyre wars between manufacturers, like the early 2000s between Bridgestone and Michelin.

The current deal with Pirelli ends in 2024 and the FIA is listening to new offers for a three-year period starting after that. Whether Pirelli stays until at least 2027 or is replaced by another tyre manufacturer remains to be seen, although we are expected to have news on the subject during this season.

Technical specifications

Following the latest shift in tyre design ahead of the new era of Formula 1 cars in 2022, things are similar for this season. The big change last year was the move to 18-inch rims, from 13-inch. The front tyres 305mm wide, with the rears at 405mm. As for the tread, the diameter is 720mm for both axles, for the slick tyres. While these rules are stable, Pirelli can make changes to the construction or the compounds of the tyres at its discretion.

The compounds

There is a variety of options available for Pirelli, suitable for every track design and surface the cars meet across the F1 calendar. The company selects three of the six available slick tyre compounds for any given race weekend, based on how much the tyres degrade at the circuit in question. It is a balancing act, as softer compounds may offer more strategy options for the times, but at tracks with heavy cornering loads excessive degradation may lead to failures.

The six compounds are numbered, with C0 being the hardest and C5 the softest. Based on track characteristics, Pirelli nominates three compounds that will be available to the teams for the race weekend. The softest among the three is called the “soft” and is marked by a red sidewall, with the next being the “medium” and marked by a yellow sidewall and the hardest being the “hard” and marked by a “white” sidewall.

The softer a compound is, the more grip it offers initially, which is why it is preferred by drivers and teams for their qualifying efforts. However, it comes at the cost of duration, as its performance drops faster. Thus, for longer stints, harder tyres are preferred. You can read more on what affects tyre degradation later in this feature.

What is a constant among all the races in a season are the two wet compounds, with tread patterns to displace water. The intermediate tyres, marked by a green sidewall, are designed for light rain and a damp track surface. This tyre has symmetrical grooves, which are 4mm deep. For more extreme weather conditions and standing water, teams can use the wet tyres, denoted by a blue sidewall. The wet tyres have more grooves, which are asymmetrical as well, with a depth of 5mm and a smaller contact patch to the surface.

The wets displace almost three times as much water as the intermediates, at 85 liters of water per second when travelling at 300kph. Those two compounds are softer than any of the slick tyres. As the tread blocks contact the wet surface, they move around and generate heat, allowing the tyre to perform better. When the track gets drier though, both compounds overheat and degrade, leading to a drop in performance.

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Photo by XPB / Icon Sport

Rules on tyres over the race weekend

When teams arrive to the track, they are allocated a specific allocation of tyres per driver for the weekend, as follows:

  • Eight sets of soft tyres
  • Three sets of medium tyres
  • Two sets of hard tyres
  • Three sets of intermediate tyres
  • Two sets of wet tyres

Each tyre set is marked by a code to ensure that a set allocated to one driver is not fitted to another’s car. Of the thirteen sets of slick tyres, two are returned to Pirelli after each practice session, leaving the drivers with seven heading to qualifying. For the drivers that get to participate in Q3, they must return a further set of soft tyres as well.

As for the race, every driver must use at least two tyre compounds during the Grand Prix. Of course, that is not the case if the race is affected by rain, when drivers use wet or intermediate tyres. In that case, drivers are not obligated to pit.

What affects tyre wear?

Tyre management has been a crucial aspect in having a successful Grand Prix for several years, as fast degradation leads to loss of grip and a huge disadvantage. However, tyre degradation depends on various factors, so let’s look into some of them.

  • Track characteristics: The circuit layout is a big factor, although that is a common factor for the whole field. A circuit with lots of fast corners punishes tyres because of the big loads, while another with slow corners and a lot of acceleration zones wears the rear tyres down faster. The track surface is another important element, as an abrasive surface is bad for tyre wear.
  • Temperature: Managing tyre temperatures is a skill that leads to great rewards in terms of performance. Of course the ambient and track temperatures are the same for everyone, and the higher they are the more the car slides around and degrades its tyres. However, drivers have to try and keep the tyre temperature in a window where the tyres perform as good as possible, as too low temperatures means the tyres does not have as much grip.
  • Suspension setup: A correct suspension setup is integral in managing tyre temperatures, leading to better tyre management as well.
  • Driving style: Ultimately, the one that can make the difference is the driver. But how is that achieved behind the wheel? The main factor is smooth driver inputs, both with the pedals and the steering wheel, as well as avoiding mistakes that can lead to slides or locking up under braking.

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