The compound range explained
Pirelli produces five dry-weather tire compounds for Formula 1, numbered C1 (hardest) through C5 (softest). For each race weekend, Pirelli selects three of these compounds and labels them hard (white sidewall), medium (yellow), and soft (red). The actual compounds used vary by circuit — a C3 at Monaco might be the hardest compound available, while the same C3 at Silverstone might be the softest.
C1 and C2: the hard compounds
C1 and C2 are the hardest compounds in Pirelli's range. They are used at high-speed, high-load circuits like Silverstone and Spa, where softer compounds would degrade too quickly. They offer less grip but much better durability, making them ideal for long stints.
C3: the middle ground
C3 is the most versatile compound. It is used at circuits that are neither extremely demanding nor particularly gentle on tires. It offers a good balance between grip and durability, making it the most commonly selected compound across the season.
C4 and C5: the soft compounds
C4 and C5 are the softest compounds, offering maximum grip but degrading quickly. They are used at street circuits like Monaco and slow, twisty circuits like Hungary, where mechanical grip is more important than durability. These compounds are typically used for qualifying and short race stints.
The 2026 change: C6 removed
For 2026, Pirelli removed the C6 compound from the range, leaving C1-C5 as the full spectrum. The C6 was extremely soft and was only used at a handful of circuits. Its removal simplifies the compound selection process and reflects the fact that the 2026 cars, with less downforce, put different demands on tires.
How compound choice shapes strategy
The compounds Pirelli selects for each weekend fundamentally shape race strategy. A weekend with C1-C2-C3 will produce races with fewer pit stops and less variation between strategies. A weekend with C3-C4-C5 will produce races with more pit stops, more overtaking, and more strategic variation.
Teams must decide how many of each compound to use during the weekend. In qualifying, they want the softest compound for maximum grip. In the race, they must balance grip against durability, knowing that a tire that is too soft will degrade before the end of the stint.