Pirelli throws open the playbook: Full tyre range in Bahrain sets up a defining test of strategy adaptation and early season nerve

 

The transition from the first week of Bahrain testing to the second session (18^th – 20^th February) represents a critical shift from structural validation to performance optimisation. By making the full C1-C5 range available, Pirelli has fundamentally changed the “physics” of the test, forcing teams to balance the increased torque of the 2026 power units (PU) with the smaller footprint of the new, narrower tyres. Pirelli’s decision to allow teams to carry over sets from week one adds a layer of “efficiency management.” Teams like Williams and Alpine, who have brought the softest, likely preserved their C1/C2 sets from previous week to use for early morning “installation” laps. This allows them to “hoard” their 24 new sets for the cooler, high performance evening sessions when the C4 and C5 are actually viable.

After a restricted opening week where teams were only permitted the hardest three compounds, the “padlock” has been removed for the final three days in Sakhir. Teams now have 24 sets available from the entire range, including the softest C4 and the “qualifying special” C5. For the first time, we see a massive split in test philosophy. Aston Martin has chosen only three softest compounds, while Mercedes is famously “going it alone” sticking exclusively to the hardest C1-C3 rubber to perfect their suspension geometry. In 2026, the out lap is a battle: you must prepare the massive hybrid battery for a 50/50 power split while simultaneously getting the narrower tyres into their tiny operating window. Drivers like Esteban Ocon have called this “conflicting” and the hardest part of the new regulations.

The biggest technical hurdle is how the tyres handle sudden downforce spikes from the new movable wings.

Mario Isola, Pirelli Motorsport Director commented: “We are quite aligned, but I believe teams are not pushing at the limit … I’m expecting to see forces increasing for the season.”

George Russell, Mercedes AMG Petronas Formula One (F1) Driver expressed concern during early testing the narrower tyres were “a step worse” because they are less forgiving at the limit.

Isola noted that the “violent downforce spikes” generated when switching from low drag to high downforce modes forced a complete rethink of the tyre’s internal construction to prevent carcass failure.

The “full range” tyre availability has revealed a massive technical hurdle: the C4 and C5 compounds are almost unusable in the Bahrain heat. On the account of the tyres are narrower, they lack the “thermal sink” to survive a full flying lap without the surface rubber “boiling.” An analytical gem discovered in the pit lane is Ferrari’s unique PU startup sequence. While other teams have to rev their engines for nearly 30 seconds to spool the turbos for a practice start, Ferrari has found a way to “snap” off the line instantly.

While the weight savings are a victory, the reduced surface area has created a “thermal nightmare” for the drivers, especially with the softest C4 and C5 compounds. As a result of the tyres being narrower, they have less mass to absorb heat. Isola warned that graining and “surface boiling” are exponentially more likely because the heat has nowhere to go. If a driver pushes too hard in sector one, the tyres are effectively “dead” by the final hairpin. Fernando Alonso noted that drivers are now “50km/h” slower” in iconic turns like 12. To save energy for the straights, drivers must “coast” through corners. This means the tyres actually cool down too much in the turns, only to be “flashed boiled” on the next straight.

By Charlie Gardner 

📸 Imagery courtesy of Formula One and Pirelli