F1 Jeddah GP: McLaren introduces new diffuser and rear updates to boost MCL39 downforce. McLaren Pushes Development with New Diffuser and Rear Package.

McLaren is looking strong: first and second after Friday’s free practice at the Saudi Arabian Grand Prix. And that was with both configurations, as the Woking-based team brought its first upgrade package. The new components were assigned to Oscar Piastri, while Lando Norris was tasked with running a standard version of the MCL39.

The updates concerned the rear end of the papaya-coloured car: Rob Marshall’s team was the only top contender not limited to tuning the car for the extremely fast street circuit, but rather brought an initial evolution aimed at developing the full potential of the MCL39.

Should Andrea Stella be concerned that the “new” McLaren driven by Oscar Piastri was slower than the “old” one driven by Norris? Clearly not, because both configurations were ahead of the competition, and the 168-thousandths gap in favour of the championship leader by three points was simply due to greater familiarity with the standard version, while the new solutions may still require some fine-tuning work.

What did the changes involve? The main one concerned the rear diffuser, which was updated in an attempt to increase total aerodynamic load while continuing to reduce wing drag, in order to improve top speed—still one of the very few weak points. The small hump in the keel, still visible in Bahrain, has disappeared, replaced by a central ramp with a continuous design leading up to the deformable structure.

In the search for better rear balance, the rear corner was also modified: in addition to a slight revision of the hot air outlet from the AP brake system, the vanes generating local downforce were also redesigned.

McLaren is unquestionably the F1 car most capable of generating vertical load on the tyres, offering both drivers a significantly wider operating window for tyre usage than the competition, especially when track temperatures are high. The question for the third free practice session is whether Norris will adopt the developed version of the MCL39, or if Oscar will abandon the upgrades to align with Lando’s setup.

The slightly lower-downforce rear wing also reappeared—this was the one McLaren began winter testing with in Sakhir, but which was set aside for the first four races of the season. In Jeddah, an ultra-fast street circuit, it proved useful again.

So far, Woking hasn’t put a foot wrong in its development choices…