How McLaren’s Greatest Strength Became Its Weakness at Las Vegas: The Plank Wear Disaster

Short Excerpt: McLaren’s mastery of ride height became its downfall in Las Vegas—unexpected bouncing and rear plank wear resulted in disqualification, despite drastic in-race efforts to limit damage.

At the 2025 Las Vegas Grand Prix, McLaren’s MCL39—a car celebrated all season for its clever ride height management—was undone by the very trait that made it a championship contender. Both Lando Norris and Oscar Piastri were excluded from the results after stewards discovered excessive wear on the plank beneath their cars, a direct consequence of unexpected high-speed « porpoising » during the race. This revealed a critical vulnerability in what had been a core McLaren strength.

THE TECHNICAL FOUNDATION: RIDE HEIGHT MASTERY

Through 2025, McLaren’s competitive edge came from its front-end compliance and ability to run lower to the ground than rivals without triggering excessive wear or instability. The car’s front skids (or « skid blocks ») were finely tuned to maximize downforce by maintaining a stable, minimum ride height without excessive plank contact—allowing McLaren to balance performance and legality across bumpy tracks.

This approach—integral to the MCL39—relied on careful calibration of suspension, aerodynamics, and chassis balance. It was particularly successful on street circuits, where precise control over ride height is vital.

WHAT WENT WRONG IN LAS VEGAS?

Vegas presented an unprecedented challenge:

• Friday’s practice sessions were disrupted by rain and red flags, depriving the team of vital data on long-run behavior and full-fuel ride height.
• Track evolution and unusually bumpy tarmac further complicated setup, increasing the risk of accidental scraping and bottom-out damage.
• Most crucially, the dry race brought « unexpected, high levels of porpoising not seen in the practice sessions, » as confirmed by Andrea Stella, which caused both cars to bounce and « squat » more than simulation data predicted.

« During the race, both cars experienced unexpected, high levels of porpoising not seen in the practice sessions, which led to excessive contact with the ground. »
— Andrea Stella, McLaren Team Principal

Because McLaren’s setup was optimized for low ride height and previous effectiveness had centered on minimizing front plank wear, the car’s rear-end—less frequently a concern—became the point of failure as rear plank wear exceeded the strict 9mm minimum legal threshold.

THE IN-RACE RESPONSE: EXTREME MANAGEMENT

As engineers realized the bouncing risk, Norris and Piastri were repeatedly told to slow significantly—in some sections, they were forced to lift off and lose 40-50 km/h to save the floor. Despite these last-ditch efforts, both cars’ planks wore down too much, ultimately registering as low as 8.9mm at the mandated measuring holes.

WHY DID McLAREN’S SECRET WEAPON FAIL?

• Unexpected Conditions: McLaren’s simulations (and most rivals’) failed to predict the degree of bouncing or rear squat seen in the race, especially after a wet Friday left almost no dry-data.
• Setup Constraints: To be competitive in qualifying and race, the car’s platform was run « on a knife’s edge » between maximum aerodynamic efficiency and legal wear. When porpoising appeared, there was little margin left to react.
• Reliance on Front-End Management: The point of excessive wear was at the rear of the plank, not the front as in previous seasons, meaning McLaren’s previous solutions were suddenly a liability rather than an asset.

THE AFTERMATH: SEARCHING FOR ANSWERS

Andrea Stella and McLaren admitted both cars « experienced unexpected, high levels of porpoising, » with the lack of dry running making it impossible to confirm true race loads and ground clearance. The team is conducting an internal investigation, considering whether minor damage also contributed to excessive floor movement and wear.

LESSONS FOR THE FUTURE

McLaren’s Las Vegas disaster is a cautionary tale:

• Even the most refined technical edge can become a vulnerability if conditions change and simulations don’t match reality.
• Ride height regulation « tricks » that exploit front skid limitations must be balanced against changing weather, track evolution, and sudden aero instabilities like porpoising.
• As F1 enters circuits with more pronounced bumps or unpredictable surfaces, success will hinge on adaptability—and, critically, on not being « betrayed » by the very trait that once gave an edge.