The Toleman TG185 was a Formula One racing car designed by Rory Byrne and was used by Toleman Motorsport during the majority 1985 Formula One season. The car was powered by the 800 bhp (597 kW; 811 PS) Hart 415T Straight 4 turbocharged engine. The car was late in arriving for the 1985 season for no other reason than a lack of tyres. In 1984 Toleman started the season using tyres supplied by Italian company Pirelli. Part way through the season though the team pulled out of their tyre contract with Pirelli and started using the French Michelins instead. However, when Michelin pulled out of F1 at the end of 1984, the team were unable to come to an agreement to use Goodyear rubber. They were also unable to get a deal with Pirelli who were reluctant to supply tyres for the team. It was only after team sponsor Benetton bought Spirit Racing and transferred their Pirelli contract to Toleman that the team were able to run in 1985.
The car was fundamentally unchanged from the TG184 apart from a revised suspension to deal with running different rubber and revised rear bodywork. The car was initially driven by former Brabham driver Teo Fabi of Italy. He was joined in the team from the 10th race (Austria) by fellow Italian Piercarlo Ghinzani. Fabi gave the Toleman Team its first and only pole position when he qualified on pole for the German Grand Prix held at the new Nürburgring circuit. Fabi set his time in the Friday qualifying session and as it rained on the Saturday no one else could beat his time. Unfortunately he got a bad start in the race due to a slipping clutch and was only 10th going into the first corner. The clutch would be the cause of the car's retirement from the race on lap 29.
The TG185 was the last F1 car for Toleman Group Motorsport. From the 1986 season the team was bought out by main sponsor Benetton and renamed Benetton Formula Ltd. Fabi's pole in Germany was the highlight of the year. After finishing 1984 in 7th place in the Constructors' Championship with 16 points (including 3 podiums by Ayrton Senna), the team failed to score a point in 1985. In fact, the TG185 proved almost totally unreliable with only 2 finishes all season when Fabi finished 14th in France and 12th in Italy while Ghinzani failed to finish a race.
Following the acquisition of Toleman the planned 1986 car, dubbed the "TG186", was simply renamed the Benetton B186. That car, powered by the 1,400 bhp (1,044 kW; 1,419 PS) BMW M12 engine went on to became the team's first ever Grand Prix winner when Gerhard Berger drove it to victory at the 1986 Mexican Grand Prix.