Valtteri Bottas sees a ‘big difference’ between Mercedes and Sauber that Audi will not like

Valtteri Bottas returned to Mercedes as their reserve driver for the 2025 Formula 1 season after Audi elected against giving the Finn a new contract to race for Sauber.

The 35-year-old spent the last three seasons with the Swiss squad after joining Sauber upon his contract with Mercedes expiring. But Bottas could not help Sauber avoid ending last year as the worst team on the grid after failing to seal a single point for the first time in his career.

Zhou Guanyu scored Sauber’s sole points for the season with his P8 finish in the 2024 Qatar Grand Prix. The Hinwil outfit have already eclipsed that tally this term after Nico Hulkenberg grabbed six points in the Australian Grand Prix after joining Sauber beside Gabriel Bortoleto.

Hulkenberg and Bortoleto are just two of the changes that Audi has made to prepare Sauber for the brand’s factory takeover in 2026. Mattia Binotto has taken charge as COO and April 1 also saw Jonathan Wheatley take over as Sauber/Audi’s new principal after leaving Red Bull.

Valtteri Bottas sees a ‘big difference’ in the ‘quality’ of Mercedes and Sauber’s engineers

Bottas and Zhou would settle for reserve driver roles with Mercedes and Ferrari to remain in the paddock over the 2025 Formula 1 season. It marked a return to Brackley for Bottas after his five years at the Silver Arrows from 2017-21 which yielded 10 wins and 20 pole positions.

READ MORE: All you need to know about Sauber from team principal to 2026 Audi future

It immediately struck Bottas after joining Mercedes from Williams to replace 2016 champion Nico Rosberg how much smoother front-running Formula 1 teams operate. It also struck him after returning from Sauber just how ‘big’ the difference is in the ‘quality’ of their engineers.

“It’s quite a big change from Sauber back to Mercedes,”. Bottas told Motorsport.com. “Just the quality of engineering and the amount of talented people in one team. There’s still a big difference because it’s a bigger team.

“Everything just maybe runs a bit smoother because of the bigger capacity and resources, which is something I definitely learned when I came to Mercedes for the first time.”

Audi will not like Valtteri Bottas seeing a clear inequality in Mercedes and Sauber’s mechanics

It will likely not delight Audi for Bottas to see a clear inequality in the skill of the mechanics at Sauber and Mercedes ahead of the German automotive giant taking over the Swiss team as a factory squad in 2026 – especially as Audi will debut as F1 introduces new regulations.

READ MORE: Everything you need to know about F1’s 2026 engine and chassis regulations

Sauber have been on a lengthy recruitment drive since the end of 2023 to prepare for Audi’s takeover in 2026. The Swiss squad also plan to open a technical centre in the UK this year to help Audi attract more talent after the issues Sauber faced getting people to move to Hinwil.

A lot of F1’s engineering talent is based in the so-called motorsport valley in the south-east of England. So, Audi may have to hope Sauber’s new UK base helps to address the inequity Bottas sees in the engineering department he said farewell to in December and Mercedes’.

While Audi could have a ‘cannon of an engine’ in 2026, doubts have long surfaced that the design of their car for the new chassis regulations might hold the rebranded Sauber squad back. Binotto admits Audi might not win for years, as well, as they must transform Sauber.