The Ferrari F399 was the car that the Ferrari team competed with for the 1999 Formula One World Championship. The chassis was designed by Rory Byrne, Giorgio Ascanelli, Aldo Costa, Marco Fainello, Willem Toet and Nikolas Tombazis with Ross Brawn playing a vital role in leading the production of the car as the team's Technical Director and Paolo Martinelli assisted by Giles Simon leading the engine design and operations. The F399 was almost identical to the previous season's F300, with small detail changes (new front wing, wheel tethers, waisted sidepods, an improved exhaust system and the use of Bridgestone tyres with four grooves instead of three). It was initially driven by Michael Schumacher and Eddie Irvine, with Mika Salo substituting for Schumacher when he broke his leg at Silverstone.