F1 | Mercedes explains the two major problems that slowed down the W16

Stricter checks on front wing flex and the introduction of a new rear suspension at Imola were the key negative points in Mercedes’ 2025 Formula 1 season. Andrew Shovlin, the team’s technical director, explained why.

Mercedes completes 2025 as the second-best team

Mercedes finished the 2025 F1 season as the second-strongest team. Led by Toto Wolff, the squad outpaced Red Bull Racing and Ferrari in the race for second place behind the unstoppable McLaren. Yet, the season was marked by two main problems that plagued the W16.

Struggles in slow corners

Over the last two seasons, Mercedes has consistently struggled in slow corners. The drivers had to use the throttle to improve rotation, which put more energy than expected onto the tires. To counter this, the team developed a front wing that could flex under certain conditions, helping the drivers in corners while preventing tire overheating.

With the introduction of stricter FIA checks from the Spanish Grand Prix onwards, Mercedes and several other teams faced renewed challenges. Andrew Shovlin, the technical director based in Brackley, explained:

“Over the last two years, we struggled to get the car to turn effectively in slow corners. Some of our rear tire temperature problems came from drivers having to use the throttle to aid rotation. This led us down a useful development path, allowing the front wing to flex. It helped at low speeds while keeping the rear stable at high speeds, and it worked well. However, this year the FIA introduced rules that significantly limited this aspect. It took some time to adapt after these rules were introduced in Barcelona.”

“The front wing change affected everyone. Our problem was too much load on the front at high speeds. These rules don’t naturally create a balanced car over a lap, so you have to force it. Teams were using the front wing’s flexibility to achieve this, and when the FIA limited it, the tools available decreased.”

Mechanical balance and new suspension

“You can try to get balance mechanically, by softening the rear axle as speed or roll increases, but the tools are limited and it takes time. Drivers have to adapt, engineers have to adjust settings, and at the same time, we had a suspension update that was mounted and unmounted from the car. We even experimented with setups. The combination of these factors made our European season more confusing than we expected.”

Regarding the rear suspension, with the flexible wing gone, Mercedes tried to compensate by looking at the best solutions from other teams. The first part of 2025 was dominated by McLaren, and that’s where Mercedes drew inspiration:

“When you’re not the fastest, you look at who is and what they’re doing. We examined McLaren’s rear suspension and understood what they were trying to do with anti-lift to maximize rear-end lowering in corners. One of the challenges with these cars is that you end up with a very narrow rear aerodynamic load window, forcing a stiff driving style. On tracks with a mix of very slow and very fast corners, compromises are necessary.”

“The other problem is that when you slow the car, you don’t get the natural balance shift we had with previous regulations, because the car doesn’t move much. You don’t get the benefit of rear lift and increased front downforce. There was a lot to reposition.”

“With these rules, we wouldn’t say we underestimated the challenge of achieving good corner balance—stability on entry, rotation at the apex, and good traction on exit—but clearly we didn’t work hard enough to transfer the strengths of the 2020-2021 cars. Now everyone reaches similar speeds in corners. The difference is how balance adapts to a given track, and that’s what distinguished teams in 2025.”

Rear suspension update at Imola

The new rear suspension didn’t just bring benefits; it also introduced drawbacks that affected much of the European season, particularly challenging rookie Andrea Kimi Antonelli.

“The big rear change was introduced at Imola, then removed. It was an attempt to go further in that direction, but it introduced other negative traits. We lost suspension stiffness, which penalized us more than expected. We had to revert and return roughly to where we were at the start of the year.”

“F1 suspensions are primarily designed to meet aerodynamic requirements, not to guarantee driving quality. You deal with compromised geometries, aerodynamic shapes, and load compliance. It’s easy to end up with something that doesn’t deliver the desired results, and that’s exactly what happened here.”

“In a way, it was positive to introduce it as an update, because if we had integrated it into the launch car, it would have been much harder to remove. Introducing something mid-season and seeing that the car doesn’t behave the same and results don’t come makes it easier to identify the problem and reverse the trend. It was fortunate that the Imola suspension wasn’t part of winter testing. The launch car’s rear end was essentially the 2024 design, with minor differences.”

Mercedes’ 2025 campaign was a story of rapid adaptation. By navigating the FIA’s crackdown on “aero-elasticity” and being brave enough to scrap a major mechanical failure, the team secured their runner-up spot—even if the path to getting there was far from linear.