TPC testing in F1: how teams use the rules’ gray zones for flexible wings. F1 TPC tests allow teams to study flexible wings using older cars, exploiting a regulatory gray area.

The possibility in F1 to carry out TPC tests (Testing of Previous Cars) during the final year of regulatory continuity is very high, using cars that were designed and built to comply with the technical regulations of any of the three years immediately preceding the current season. To clarify, in 2025 it is possible to use cars that competed in the 2023 World Championship or in earlier seasons.

These tests were intended to allow reserve drivers or promising academy drivers to gain experience behind the wheel of F1 cars. Since in previous seasons several main drivers—even highly experienced ones—have carried out multiple such tests, the FIA has imposed a maximum mileage limit for drivers registered in the championship of 1,000 kilometers. The main guidelines are as follows:

Each team can carry out up to 20 TPC test days per year.
Official drivers can drive a maximum of 1,000 km in total.
The 1,000 km can be divided across a maximum of 4 of the 20 available TPC days.
No updates or modifications to the car are allowed.
TPC tests are prohibited at circuits within two months of a Grand Prix at the same venue.

TPC tests have purposes far broader than the spirit of the regulations
After this necessary introduction, it is worth asking what the real purposes of these tests are. They are very frequent in the current season, conducted by main drivers and young talents who are unlikely to participate in an official free practice session. In the top category of motorsport, no second is wasted except to improve car performance, so the real reasons for these tests must be sought elsewhere.

These sessions are an excellent opportunity to verify data correlation between simulation contexts and information gathered on track. Wind tunnels, CFD systems, and team simulators are constantly evolving, and having access to real-world data is essential to evaluate how closely what was studied in a hypothetical context matches reality.

The potential gray area of TPC tests
F1 teams are required to inform the FIA at least 72 hours in advance of a TPC test, allowing for an observer check. Teams must also provide the Federation with the following information:
The exact specifications of the car(s) to be used,
The name(s) of the driver(s) and type of activity,
The date(s) if multiple tests are planned,
The expected duration and purpose of the activity.

A crucial point concerns the difference between F1 cars and the technical regulations of the reference year. Essentially, if a 2023 car is used, it must comply with the regulations of the championship it participated in. Now, let us allow a touch of skepticism. TPC tests conducted by F1 teams are excluded from the budget cap, as they do not count toward expenses related to current-season car performance.

But are we really sure about that? Consider the new TD018 technical directive, which imposes stricter limits on front wing flexibility. From the Spanish Grand Prix, these flaps have been subjected to a load of 60 Newtons (about 3 kg) and cannot flex more than 3 millimeters, compared to 5 mm previously allowed. Regarding the main plane, with a vertical load of 1,000 Newtons (around 100 kg), the maximum permitted deflection will be 10 millimeters, compared to the previous 15 mm.

By producing a front wing geometrically identical to a 2023 car’s, but capable of withstanding the stricter tests coming at Montmeló, teams would still be compliant with the less restrictive regulations of that season regarding wing flexibility. Staying in the realm of hypothesis, some teams may have produced front wings identical to those of the cars used in TPC tests.

F1, the possible work of teams on flexible wings
The difference could lie in construction characteristics that allow the new FIA flex tests to be passed. That said, what could be the advantage? Engineers could evaluate, even on a car two years old, the impact of the new directive on car balance.

This concerns aerodynamic efficiency and airflow management, based on the assumption that the front wing is crucial in directing air according to precise criteria. Unable to test this on current cars, comparing it on technical designs from two years ago can still provide highly valuable evidence to apply to 2025 cars. To think the worst may be wrong, but sometimes it hits the mark.