Unpacking the 2023 F1 Pirelli Tires

Tire compounds and degradation

Tires are the most variable part of the Formula 1 car. Teams change tires once or twice during a race as part of their strategy and also change tires as they wear down.

Tire Compounds

Every race weekend, the FIA designates three slick (no groove) tires—softs, mediums, and hards from six options or tire compounds released by Pirelli for the season. Soft tires are marked red, mediums yellow, and hards white.

FIA Slick Tire Compound designations (softest to hardest):

C5: Softest tire, has lots of grip, used on slower tracks (such as street circuits)

C4: Fast warm up, used on less abrasive tracks (so it lasts longer), used often

C3: Very adaptable—it can be used as the hardest, softest or medium for the three tire selection

C2: Suited for faster and more abrasive tracks

C1: Closes gap in performance between C0 and C2. New compound in 2023.

C0: The hardest tire, built for endurance on track but that can also take away from lap performance, has the maximum resistance to heat. The 2022 C1 tire is now C0.

Teams develop their race strategy based on the designated tires for the weekend. They have to make sure they are getting the best tire performance possible without compromising endurance. For example, choosing the softest tire on an abrasive track will provide peak performance for about 10 laps but then wear down very fast.

Harder tires are often selected for newer tracks so that enough data can be collected on tire wear; teams can then make strategy changes without worrying about an abrasive track causing excessive wear on soft tires.

Racing in rain can cause chaos when drivers are on slick tires. That is why Pirelli also has two types of wet tires for every race in addition to the six slick options.

FIA Wet Tire Designations:

Intermediate (green): Used on either a dry track with light rain, or a wet track that is drying off. Inters bridge the gap between slicks and wets and are for conditions that aren’t fully wet or dry. They have shallower grooves and the rubber is softer than full wets. Their less sticky rubber compounds (compared to slicks) have less friction, requiring a relatively long time to warm up and create the necessary amount of grip for high performance.

Full Wet (blue): Effective for heavy rain. Full wets have treads to channel the water to the side of the tire and increase surface friction. This prevents aquaplaning and increases grip in rainy conditions.

Parts of the Tire

All tires weigh between 9.5-11.5kg and have an 18in diameter. However, the rear wheels are larger than the front wheels because F1 cars are rear-wheel drive. Having a larger rear tire increases the contact space between the ground and rubber creating more grip and powering acceleration. The front tire has a width of 305mm and the rear a width of 405mm.

Tire compounds are composed of several layers.

Outer layer: rubber compounds from C0-C5 (or wet tire rubber). Pirelli keeps the exact composition of each compound a secret.

Second layer: steel belts to help the tire keep shape. Usually, there is a layer of Kevlar or Nomex (made from synthetic fibers highly resistant to heat) between the rubber tread and belt.

Side of tire: carbon fiber is added to the sides to help with stability which can increase cornering speeds.

Adhesives are used to put these layers together

Tire degradation

Tires need to be changed multiple times during a race due to tire degradation. Tire degradation negatively impacts performance as there is reduced grip which can increase braking distances and destabilize the car.

There are many ways a driver can attempt to preserve their tires. Just like how driving in heavy traffic with lots of braking and accelerating can drain your gas tank, abrupt movements in a F1 car can affect tire wear. Drivers can brake earlier before turns and drive less aggressively to preserve their tires. Additionally, both the drivers and the team can monitor tire temperatures because tires that are too cold or too hot will wear down faster. Tire pressure and compounds are also other factors that drivers can keep track of to try to preserve their tires while still performing well. An example of the effect of tire compound on racing time is show below in a graph of Max Verstappen’s lap times in the 2023 Spanish GP.

Max started on mediums, changed to hards on lap 26, and then changed to softs on lap 52. The average lap time per tire was 80.4 seconds for mediums, 80 seconds for hards, and 79.3 seconds for softs. The mediums had a lower average lap time compared to the hard tire most likely because they were used in the beginning of the race when the car was fully fueled. Fully fueled cars are much heavier and thus drive slower. As the cars go through the laps of the race, they lose weight and become faster. While there are a lot of other factors that affect speed, the impact of tire type and wear on Verstappen’s lap times are prominent.

Wrong Tire Choices

In 2022, Ferrari made many poor tire and pit stop decisions that ultimately cost Charles Leclerc the Driver’s Championship despite the speed of his car. One of these detrimental decisions came up during the 2022 Hungary GP where the Ferrari car was favored to win. Ferrari started the race on mediums and was doing well until Red Bull undercut them by pitting Max earlier to gain an advantage by changing to new medium tires. Ferrari panicked and quickly pitted Charles, inexplicably giving him the hard tires that had performed terribly in the Formula 2 race that morning.

Leclerc pits for hard tires in the 2022 Hungary GP

It took 10 long laps for Leclerc’s hard tires to warm up and by then the race was over and Verstappen took the win even though he had started the race at P10.

This is why tire strategy can play a huge role in driver performances, potentially making all the difference in the Championship outcome.

Data

Max Verstappen’s lap data for the 2023 Spanish GP

Sources:

1. https://www.pirelli.com/tires/en-us/motorsport/f1/tires

2. https://toptirereview.com/f1-tire-vs-normal-tire-a-technical-analysis/#:~:text=F1%20tires%2C%20which%20are%2018,a%20normal%20passenger%20car%20tire

3. https://www.formula1.com/en/latest/article.the-beginners-guide-to-formula-1-tyres.61SvF0Kfg29UR2SPhakDqd.html

4. https://f1chronicle.com/how-formula-1-tire-management-works/#:~:text=Teams%20and%20drivers%20can%20use,One%20is%20pit%20stop%20strategy

5. https://www.thesun.co.uk/sport/19382601/lewis-hamilton-max-verstappen-ferrari-hungary-grand-prix-f1/ (photo)