The McLaren MP4-20 is a Formula One Racing car that was built by McLaren. It was designed by Adrian Newey and Mike Coughlan for the 2005 Formula One World Championship.
The car chassis was new design after the failure of the MP4-18 and MP4-19.
The new car featured revised aerodynamics and suspension for the 2005 regulations, including a raised front wing, smaller diffuser and rear wing moved further forward.
A shorter wheelbase was used to maximise the Michelin tyres performance.
The car featured distinctive 'horn' wings fitted to the bodywork behind the overhead air intake in an attempt to claw back as much downforce as possible lost through the FIA's rule changes.
The wide, flat nose design was initially trialled on the MP4-19 at the 2004 Italian Grand Prix, but not retained for the rest of that season. It was fully utilised for 2005.
This would be McLaren's last car to feature the grey and black livery of primary sponsor West cigarettes, a partnership which began with the MP4/12 in 1997.
The Mercedes engine was the most powerful in F1 that year but suffered reliability problems which cost R�ikk�nen the world championship to Fernando Alonso and McLaren the Constructors Championship to Renault despite McLaren winning 10 races to Renault's 8 wins.
R�ikk�nen won seven races and was in a position to win at least three others but the car's unreliability cost him the title. Montoya also suffered from reliability problems which cost him a potential win in Hungary and potential podium finishes in France and China.
Continual development throughout the year made the MP4/20 the fastest car in F1 from mid-season onwards, as was seen by the number of pole positions and fastest laps accumulated by both R�ikk�nen and Montoya.
R�ikk�nen and McLaren eventually finished second in their respective championships, whilst Montoya finished fourth in the drivers' standings.