Pirelli's Hungaroring tyre test keeps F1 engineers working through the summer break

Formula 1's mandatory summer shutdown is the one point on the calendar where the paddock goes quiet. Factories go dark, wind tunnels stop spinning, and simulation racks power down for a fortnight. Except that three teams and drivers have been at the Hungaroring this week, running flat-out for Pirelli.

Pirelli rents the circuit immediately after grands prix while the infrastructure, marshalling, and track rubber from the race weekend are still in place. Running a dedicated test just days after 40 cars have laid down rubber provides a baseline impossible to replicate at a cold, green circuit.

The Hungaroring combines 14 corners over 4.381 km, with a surface notoriously abrasive in the early part of any session. The track rubbering-in effect across a weekend is significant here, which is why Pirelli wants the post-race conditions for development running.

While most teams are now on a mandated break, three drivers have been on-site. The work is not about setup, strategy, or driver comfort. It is pure data-gathering for Pirelli's next tyre construction.

What a tyre test actually measures

Pirelli does not bring soft, medium, and hard compounds to a development test and ask drivers which they prefer. Drivers run with tyres fitted with internal sensors that log carcass temperature, inflation pressure rise, and surface degradation across a stint.

Pirelli's current development focus covers both the load-bearing internal structure, made of textile and steel belts, and the outer compound of rubber that produces grip. The manufacturer is preparing for regulation changes coming for the 2026 season.

During a test like this, drivers complete runs designed to mimic different race scenarios. A short, aggressive run tests peak grip and thermal degradation. A longer run on high fuel tests wear life and how the tyre performs as it loses mass. Each run produces a dataset that Pirelli's engineers compare against their pre-test simulation models.

The carcass pressure riddle

The most important logged value Pirelli extracts from these runs is the TTDTM, or Tyre Temperature Distribution over time. As a tyre runs, the internal air heats and expands. This pressure rise changes the contact patch, the shape of the tyre where it meets the track, and therefore the grip level.

If the pressure rises too quickly, the tyre overheats and loses performance. If it is too stable, the grip window becomes too narrow. Pirelli is constantly searching for a carcass construction that provides a wide, predictable operating window. At the Hungaroring, the constant load changes through the technical second sector provide a harsh test for carcass stability. The data from these three drivers will directly inform the prototype specifications Pirelli homologates for the remaining races and next season.

The hidden cost of development running

For the three teams participating, the summer tyre test is a mixed blessing. They get valuable kilometres, with their drivers logging time on track while rivals are on a beach. But they also have to staff the event, run the cars, and burn through mileage on components like gearboxes and power units.

A team competing for championship position wants to save parts for the remaining races. A team in the midfield or lower positions might welcome the chance to run on a rubbered-in track and collect data on their own package while fulfilling the Pirelli contract. Which teams chose to send their cars and drivers to Budapest rather than shut down immediately is a quiet indicator of competitive priorities.

Spa demands the opposite

The information collected at the Hungaroring will be processed over the summer break, but it will not immediately feed into the next race weekend. Formula 1 returns at Spa-Francorchamps for the Belgian Grand Prix, a circuit at the opposite end of the spectrum from the twisty Hungarian venue.

Spa is a layout of long straights and fast sweeps, places where the tyre is not subjected to continuous lateral load but to high thermal cooling and then sudden loading through corners like Eau Rouge and Pouhon. If the Hungaroring tests carcass stability under constant load, Spa tests the tyre's ability to switch from cold-running to high-grip in an instant.

The Hungarian test data will not unlock the Spa setup. It will, however, provide Pirelli with another piece of the puzzle as they finalise a tyre construction that can handle the demands of a calendar that runs from Monaco to Monza to Suzuka. For three drivers, the summer break began with one more day of hard, unglamorous engineering work.