McLaren has brought an extensively revised MCL40 to the Azerbaijan Grand Prix as the Woking team searches for the development step that could establish it as Mercedes’ most credible challenger. New sidepods, a revised floor, airbox and engine cover, changes around the rear suspension and diffuser, and an evolved rear wing make the Baku package so extensive that the car can effectively be viewed as a B-specification version of the MCL40.
McLaren had already announced that its MCL40 development programme would be divided into three distinct phases, with one clear objective: becoming a genuine threat to Kimi Antonelli’s dominant Mercedes. After its recent surge in competitiveness, Baku now represents an important test of whether the latest changes can take the team another step closer to the benchmark established by the W17.
The development comes after a run of increasingly competitive performances, including Madrid, where McLaren appeared capable of victory before the timing of the Virtual Safety Car changed the race. That episode subsequently fuelled a wider discussion about Formula 1’s VSC regulations after Kimi Antonelli’s Madrid victory.
McLaren’s MCL40 Baku upgrade targets more downforce and less drag
There is little doubt that the modifications developed by Rob Marshall’s technical group significantly change the appearance and aerodynamic philosophy of the MCL40 seen until now. The work is focused on two specific objectives: increasing aerodynamic load while simultaneously reducing drag.
Those aims are normally difficult to reconcile because additional downforce generally comes at the cost of increased aerodynamic resistance. McLaren is nevertheless attempting to achieve both with an ambitious package that touches several interconnected areas of the car.
The scale of the changes follows the radical MCL40 sidepod concept already revealed in Baku, but the modifications extend considerably further than the radiator inlets alone.
New McLaren sidepods follow an Audi-inspired inlet concept
The sidepods are completely new and have been extensively redesigned. Their radiator inlet, previously relatively large in its traditional configuration, now follows a philosophy similar to that introduced by the Audi R26 this season.
Instead of the conspicuous triangular shape used previously, when the intake extended towards the rear-view mirror stay, the opening now occupies a much smaller area and resembles a trapezoid. The change has been made possible by a different approach to the internal fluid dynamics of the sidepod.
McLaren has altered both the airflow passing through the radiators and the rate at which air is exchanged. The intended result is for the Mercedes-AMG F1 M17 E Performance power unit to receive effectively the same level of cooling as before while generating significantly less aerodynamic resistance.
The outer section of the inlet consequently creates a sidepod shape that strengthens both the undercut beneath it and the outwash effect. Previously, the upper part of the sidepod followed a curved trajectory before descending towards the outer edge of the floor. It has now become more flared, with a noticeable reduction in the amount of lateral surface area.
McLaren changes cooling layout and rear suspension airflow
The hot-air outlets in the engine cover have also been modified. With less cooling air entering through the revised sidepod openings, the hot-air extraction area inevitably has to increase. For Baku, the MCL40 features two small vents above the central section of the sidepod together with a more prominent opening in the engine cover.
McLaren has also modified the carbon-fibre fairings around some of the rear suspension arms. Their geometry has been changed to suit the revised airflow pattern, with the aim of improving the efficiency of the diffuser.
The diffuser itself has also been revised so that it can exploit the new flow structures generated by the updated floor. The interaction between the bodywork, floor, suspension fairings and diffuser is therefore central to the overall concept rather than each component operating as an isolated upgrade.
It is another sign of how aggressively McLaren is continuing to develop the MCL40 despite the championship having already entered its closing phase.
MCL40 floor edge evolves a Mercedes concept
The floor edge immediately ahead of the rear wheels has also been redesigned. McLaren has evolved the complex solution Mercedes introduced in Canada in an attempt to strengthen the outwash effect along the outer edge of the floor.
What was previously a single diagonal element has developed into two shaped flaps. These generate an additional airflow effect in one of the car’s most aerodynamically sensitive areas, helping to influence the wake generated around the rear of the MCL40.
The decision to evolve a Mercedes idea is particularly notable given the competitive target McLaren has set itself. The Woking team is trying to close the gap to a rival that has established the reference package in 2026, even though Toto Wolff has acknowledged that Mercedes still has further W17 development potential.
New airbox follows Red Bull RB22 concept
Almost every detail reinforces the impression that the MCL40 has effectively become a B-spec car. As has happened on several other 2026 Formula 1 machines, McLaren has also redesigned the airbox.
The previous opening had a more ogival profile, but the new version follows a concept similar to the Red Bull RB22, adopting a more triangular yet rounded shape. The thinking behind the change is to improve the aerodynamic efficiency of the rear wing, including through its central section.
Another visible change can be found on the engine cover. The dorsal fin has lost its previous stepped profile and now features a smoother, continuous curvature with a more streamlined overall shape.
McLaren evolves reversible rear wing for Baku Straight Line Mode
Such an extensive aerodynamic package could only be accompanied by a revised rear wing. McLaren has brought another version featuring reversible flaps, already representing an evolution of the H-shaped specification seen at Monza but not used at Madring.
The objective is to reduce aerodynamic drag when the car enters Straight Line Mode. With the wing open, McLaren is searching for greater maximum speed, an especially important factor on Baku’s exceptionally long flat-out section.
The lateral endplates, meanwhile, are configured to provide greater load and feature three-dimensional profiling. The combination is designed to allow McLaren to minimise drag on the straights without sacrificing more downforce than necessary through the corners.
That balance between aerodynamic load and efficiency is crucial if McLaren is to take the fight to Mercedes consistently. The W17 has set a formidable standard this season, with Mercedes’ 2026 performance underlining the scale of McLaren’s challenge.
Baku will reveal whether McLaren can become Mercedes’ main challenger
McLaren’s Azerbaijan package is therefore far more than a circuit-specific adjustment. The redesign brings together a smaller radiator inlet, reshaped sidepods, revised cooling outlets, new rear suspension fairings, developments to the floor edge and diffuser, a different airbox and engine cover, and an evolved reversible rear wing.
The objective running through all of those changes is the same: extract more downforce from the MCL40 while reducing the drag that has limited the car’s straight-line performance.
Baku will provide the first indication of whether those ambitious targets have been achieved. If the extensive package delivers the expected gains, McLaren could strengthen its claim to being the team most capable of challenging Mercedes for the remaining victories of the 2026 Formula 1 season.
