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The wind direction at the circuit can change drastically during the day, a significant factor given the importance of aerodynamics to modern Formula One cars. It is then hard to find a good setup since cars can have massive aerodynamic drag and understeer on one part of the circuit in the morning, but suffer oversteer at the same part of the circuit in the afternoon. A given tyre compound can work well when tested, but not so well a couple of months later. These changeable conditions can make for unexpected performances from some teams during the race.
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