F1 | A millimeter challenge: why managing skid plank wear is so complex
The disqualification of both McLarens in Las Vegas has brought the issue of ride height back into the spotlight: a delicate balance between performance and regulations. But what makes it so difficult for teams to manage skid plank wear, especially in real time, and what technical challenges differentiate the top teams? Let’s explore.
The McLaren disqualification at Las Vegas highlighted a critical aspect of the ground-effect era: ride heights and the wear on the plank under the floor. Generally, the closer a car travels to the ground, the more downforce and performance it generates from the floor — but only if excessive scraping is avoided.
Achieving the perfect balance is far from simple. This season, multiple FIA inspections have led to several exclusions, showing how teams constantly operate at the limit. McLaren’s case is particularly illustrative, as the management of ride height has been one of the key factors making the MCL39 so effective.
Comparing McLaren with Ferrari after the US Grand Prix, the SF-25 has suffered from plank wear more than any other car, limiting performance on several occasions. McLaren, by contrast, has been able to run lower without hitting the same limits as its rivals — a significant advantage.
Each team experiences plank wear differently, even at the same ride height, because each car’s aerodynamic map distributes load and degradation uniquely. The areas under the floor and the contact points with the track vary according to the car’s design philosophy, which is why the FIA monitors multiple areas of the plank.
Teams aim to generate downforce primarily at the rear, near the diffuser, while simultaneously moving the contact point forward, where sparks usually originate. This explains why sparks are only a partial indicator of plank wear across different teams, within certain limits.
“I think many teams struggle with rear plank wear. But those who can distribute it forward can run lower than others. It’s very clever — those who manage it gain a competitive advantage. You want to create load at the back, but shift the contact point forward. Whoever achieves that can run lower,” says Inaki Rueda, Sauber’s sporting director.
It’s a subtle balancing act established even before the season starts, during the car’s fundamental design — aerodynamic and especially suspension, an area where McLaren invested heavily with innovative solutions this year. For Ferrari, correcting this during a race is extremely difficult, and it can become a limiting factor for the entire season.
This is why the MCL39 has often been able to run relatively low compared to rivals, generating more floor downforce. However, this can also backfire: when porpoising occurs, the platform loses stability, causing the car to scrape the track more than expected.
McLaren is not immune. In Barcelona, running very low in practice, the car suffered excessive porpoising, scraping the track in high-speed corners and requiring a higher setup for qualifying. That problem was managed in time, but at Las Vegas, the team was caught off guard.
During the race, the two MCL39s clearly “bounced” more than competitors, even on the same line. This was not intentional; if it had been detected in practice, the team could have adjusted the ride height. Instead, with no long runs or wet conditions in practice revealing the issue, McLaren kept an aggressive setup, likely with a softer car.
Estimating plank wear in real time, especially when porpoising occurs, is extremely complex. There are no sensors directly measuring wear; data must be inferred through simulations and algorithms combining speed, load, ride height, and observations from practice.
For teams operating on fractions of a millimeter, free practice or sprint data is vital, offering a real-world benchmark for simulations. However, some weekends — like in China — bring rapidly changing conditions, making readings even more difficult. What has always been McLaren’s strength — running low for maximum downforce — became its limiting factor in Las Vegas.
Estimating plank wear in real time, especially when porpoising occurs, is extremely complex. There are no sensors directly measuring wear; data must be inferred through simulations and algorithms combining speed, load, ride height, and observations from practice.
It is the ultimate high-risk, high-reward game in modern Formula 1, and one that will only get more intense as the 2026 regulation shake-up approaches.
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