During the off-season, Toleman ran into difficulties over tyre supply and was only able to compete in after Spirit experienced financial collapse, allowing Toleman to take over its Pirelli tyre supply. The roots of this situation lay in Toleman's decision to abandon Pirelli after the 1984 San Marino Grand Prix in response to Michelin and Goodyear's performance advantage. Due to the dispute, Toleman had opted to sit out the first day of qualifying at Imola and this, along with a fuel pressure problem on his Hart powered TG184 in the final session resulted in Ayrton Senna not qualifying for a Grand Prix for the only time in his career. Toleman had already aggravated Goodyear with the same behaviour (that time in favour of Pirelli) in Formula Two, so Michelin was the only alternative. When Michelin subsequently announced its withdrawal from F1 effective at the end of 1984, it left Toleman with bridges to mend.