McLaren MCL39 Tech Review: How Sidepod Design Takes Inspiration From Mercedes, Not Red Bull

Mercedes might have struggled immensely in terms of understanding and nailing the ground-effect car concept. However, their experimental development, especially on the sidepod aspect, may have given McLaren some inspiration for its 2025 car — the MCL39.

Mercedes were hoping to be the pioneer of the ground-effect era by introducing the zero sidepod design in 2022, when the ground-effect regulations were first introduced. As that concept failed terribly, the Brackley outfit started to experiment more with their sidepods and even revamped their 2024 car to introduce proper sidepods with unique inlet designs.

The P-shaped sidepod became a major topic of discussion in the F1 tech community. However, it did not yield Mercedes any success on the track. The reason was that their aero platform — including their floor, front wing, and suspension wasn’t in alignment with the sidepod design, often putting the team in a fix.

McLaren, though, seems to have figured out a way to inculcate an iteration of the P-shaped sidepod to its 2025 challenger — which they hope could help them secure both championships this season. But why have the Woking-based outfit gone down a road that Mercedes took instead of trying to emulate their title rivals, Red Bull?

Firstly, Red Bull have themselves struggled last season with their ambitious RB20 concept that was an attempt to reinvent the wheel on their sidepod design, floor, and suspension geometry. However, it backfired for them as the suspension was too rigid for kerbs and bumps, and the car’s handling worsened the cornering performance for drivers.

While Red Bull were figuring out a solution to their issues last year, McLaren significantly out-developed them on all fronts. Besides introducing tweaks in the suspension geometry and some floor elements for their 2025 car, the change in their sidepod inlet design may be an attempt to optimize their airflow and unlock a few more tenths.

McLaren’s revised sidepod inlet

Former Mercedes aerodynamicist Kyle Forster analyzed the MCL39’s revised sidepod design while bringing up its supposed Mercedes inspiration. Firstly, he stated how even the Alpine car had a similar detailing with some of its inlet designs last season.

However, McLaren seems to have figured out a way to fit in this sidepod inlet with their overall aero concept, which has become the benchmark in terms of ultimate performance since last year’s Miami GP. Ideally, they would hope to not face issues like Red Bull after their innovation on the sidepod design 12 months ago.

Forster stated how the “intake stays detached and goes the whole way down” parallel to the monocoque body. The initial pictures of McLaren’s shakedown of the car in Silverstone did not show where the edge of the inlet meets with the bodywork.

Regardless, it is quite the modification compared to the 2024 MCL38, where the sidepod intake “sat underneath this forward lip and just went to the body”, per Forster.

The ex-Mercedes aerodynamicist feels that McLaren could improve their “[air]flow quality”, in general, by decreasing any sharp corners as they have done with their revised sidepod inlets. Whether it works on track to improve their aero performance remains to be seen.

Forster also stated that McLaren have made minor changes to their suspension geometry, which includes enhanced anti-dive and anti-squat on the front and rear suspensions, respectively. All in all, he feels the MCL39 is an evolution of last year’s car itself. However, McLaren team principal Andrea Stella begs to differ.

Stella deems McLaren’s 2025 car upgrades ‘substantial’

McLaren haven’t played any games in unveiling their 2025 car at Silverstone. While there are still two weeks until pre-season testing besides the F1 75 season launch in London happening next week, the Woking team seems confident about their car design and performance, considering how they have already openly fielded the ‘real’ car.

When asked by The Race about the changes to the MCL39, Stella said, “Pretty much every fundamental component of the layout has been subject to some innovation.” McLaren’s top brass had hinted at making significant upgrades to their 2025 car despite ending the 2024 season with the fastest and most adaptable car in the field.

Stella underscored how they have “substantially” optimized and modified many of its parts right from the front wing to the crash structure. And the visible changes on the car so far add weight to the Italian engineer’s claim.

Stella has assured that this version of the MCL39 — that they drove in the shakedown in Silverstone — will mostly be the one to run in the Bahrain pre-season test later this month. It is natural, though, that the Woking team may further fine-tune the car to bring some new parts at the season-opening race in Australia.