Softer, faster: the C6 tire arrives in Formula 1 at Imola

The connection between a Formula 1 car and the track relies entirely on its four tires. These are responsible for transferring the power generated by the power unit to the ground. At speeds often exceeding 300 km/h, the friction forces generated are considerable, especially in the corners. Before exploring the range of tires used in Formula 1 and the introduction of the new compound, let’s briefly recall the main rules established by the FIA regarding their use.

The tire regulations in F1, a key element

During a typical weekend, each driver has 13 sets of slick tires (8 soft, 3 medium, 2 hard), as well as 7 wet track tires (4 sets of intermediates and 3 extreme wet). During the three free practice sessions, teams are required to return two sets of tires after each session, reducing their stock to seven sets available for qualifying and the race. Finally, in the case of a dry race, the regulations require each driver to use at least two different types of slicks, which necessitates at least one pit stop.

Sprint weekends follow slightly different rules: drivers have 12 sets of slicks and must use new mediums in SQ1 and SQ2, then new softs in SQ3 if they make it there. After the Sprint race, they must return the set of tires they used the most. A color code on the tire sidewalls allows them to be easily identified: red for soft tires, yellow for medium tires, white for hard tires, green for intermediate tires, and blue for extreme wet tires.

The arrival of the C6, an even softer tire

Exclusive supplier of Formula 1 since 2011, with a partnership recently renewed until 2027, Pirelli continues to innovate with the introduction of a brand new ultra-soft tire. Until now, the range of slicks went from C0 (the hardest) to C5 (the softest). Now, the C6 is added to this hierarchy as the softest compound offered this season.

C1 – The Ultimate Hard Compound. The hardest compound is used for the most demanding circuits. It is designed to offer maximum resistance to heat and extreme forces and is capable of performing very long stints. It is therefore favored for very abrasive tracks.

**C2 – Designed for Extreme Durability**. The second hardest compound remains well-suited for fast, hot, and abrasive tracks. C2s are sometimes offered for new circuits.

C3 – A Versatile Compound. This compound is extremely versatile and can be used as the hardest, medium, or softest of any selection of three compounds. With an excellent balance between performance and durability, it is well-suited to a wide range of conditions.

**C4 – Fast temperature build-up and superior grip**. This compound is designed to perform well on low severity tracks, where rapid warm-up is necessary to achieve maximum performance as early as possible. This tire is widely used throughout the season.

C5 – Flexibility for speed bursts. These tires are designed for the slowest tracks, with little wear and degradation, where maximum mechanical grip from the rubber is required. They are normally used when the asphalt is exceptionally smooth.

C6 – The King of Performance. This new compound introduced this month, also with a red band, goes even further in the quest for grip and performance by being softer than its C5 predecessor and stands out for increased performance and better grip. Its use will be limited to street circuits or those with low abrasion.

Choices tailored to each track for more spectacular races

Pirelli adjusts its tire selection based on the characteristics of each circuit. A few weeks before each Grand Prix, the Italian manufacturer selects three compounds from its range to meet the specific demands of the circuit. For example, for the Bahrain Grand Prix, held on abrasive asphalt, the hardest compounds (C1, C2, and C3) were chosen. Conversely, in Miami, it was the C3 (hard), C4 (medium), and C5 (soft) that were used.

This desire for strategic diversity also responds to some criticisms expressed in recent seasons, particularly during this year’s Japanese Grand Prix, deemed somewhat dull due to overly predictable tire wear (for reference, C1, C2, and C3 were used). The introduction of the C6 could therefore encourage more dynamic races, with more pit stops and overtaking.

In 2025, we have more options than in 2024. The performance differences between the compounds are better calibrated, with less overheating and graining. This allows us to offer more strategic solutions to the teams, explains Mario Isola from Pirelli.

A strategic combination to watch from Imola

At Imola, the C6 (Soft tire) will be accompanied by the C5 (Medium tire) and the C4 (Hard tire), forming the softest tire trio offered so far in 2025. This selection offers a wide range of strategic possibilities: the C6 is a highly performant tire over one lap, but potentially very tricky to manage during a race. This new compound should allow drivers to achieve faster lap times, promising explosive qualifying sessions, and possibly even a circuit record established by Valtteri Bottas in 2020 with a time of 1’13”609.

With the introduction of the C6, Pirelli adds a key piece to its strategic puzzle for 2025. It remains to be seen how the teams will exploit this innovation at the Imola circuit. McLaren, which has shown excellent management of tire degradation at the start of the season, could gain an additional advantage from this new compound. It will therefore be particularly interesting to monitor their performance in Italy. We’ll find out in a few days.