The Kick Sauber C45 is a Formula One car designed and constructed by Stake F1 Team Kick Sauber to compete in the 2025 Formula One World Championship. The car is driven by Gabriel Bortoleto and Nico Hülkenberg in what is the team's final year before transforming into the Audi factory team from onwards.
Background.
Development context.
Sauber unveiled the car's livery at the F1 75 Live event on 18 February 2025. The C45 chassis was later revealed in digital renderings immediately following the event. The car has been designed to build on a late-season aerodynamic and cooling package brought to the Kick Sauber C44. After experiencing significant stiffness and handling issues during pre-season testing, technical director James Key brought forward an upgrade package that was due during the early rounds of the season. As a result, the cars that appeared at Albert Park for the first round bore many aerodynamic and internal differences to the pre-season version of the car.
Competition and development history of the C45.
The C45 made its public debut at Bahrain International Circuit during official preseason testing. Prior to the car's debut, both drivers completed testing programmes in the C44 at Yas Marina and in the C42 at Circuit de Barcelona-Catalunya under the Testing Previous Cars (TPC) programme. 
Debut and first points.
On its competitive debut at the 2025 Australian Grand Prix, Bortoleto reached Q2 in qualifying, but retired from the race, and Hülkenberg finished in seventh position to score six points. As a result, the C45 achieved more points in its first race than its predecessor scored throughout the entire 2024 season.
Spanish Grand Prix upgrade package.
Sauber brought upgrades to the car at the Spanish Grand Prix. Starting fifteenth, Hülkenberg bettered his seventh-place finish at the Australian Grand Prix to finish in fifth, which marks Sauber's highest finish of the ground effect era since the 2022 Emilia Romagna Grand Prix, where they competed as Alfa Romeo. 
Bortoleto outqualified his teammate, but remained in twelfth by the chequered flag. Hülkenberg finished in eighth in Canada, with Bortoleto in fourteenth and out of the points. 
Sauber then scored a further six points between Hülkenberg, who started last, and Bortoleto, the latter bringing the team to Q3 for the first time this season and obtaining his first career points, at the Austrian Grand Prix, also marking their first double-points finish since the 2023 Qatar Grand Prix, again as Alfa Romeo.
Sponsorship and livery.
The livery is the same as last season with a green and black colour in relation to the main sponsor Stake.
For the Miami Grand Prix an alternative livery was presented with the colours applied as paint, inspired by the street art of the city. For the Spanish Grand Prix another was presented; this time the colours adopted a "pixelated" style inspired by video games, the main content of Kick.
Complete Formula One results.
 Season still in progress.