Is there a limit on the number of tyres used?
There isn’t a limit for testing, but teams have 110 sets of tyres to see them through a whole season, including the winter tests, so they can’t go totally crazy.
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What special ‘bits’ can the teams use on their cars?
There are two main ones you’ll see during testing. The first is flow visualisation paint, better known as ‘flow-vis’, a fluorescent powder the teams mix with a light oil like paraffin, and then daub onto the car to show air flow patterns.
The second are aero rakes, a scaffold-like series of ‘pitot tube’ sensors which measure dynamic pressure and can then paint a picture of the flow structures coming off things like the front wing, the front tyres and so on.
What’s that green light you sometimes see on the back of a car?
For the drivers who just have an International A licence but don’t yet have an FIA Super Licence, their cars are required to have a green light illuminated on the back of the car during their running.
Will the fastest car in testing usually win the title that year?
Not necessarily. Firstly, Barcelona is actually a fairly unrepresentative track, requiring teams to run near-Monaco levels of downforce on their cars. That can sometimes mean that cars which aren’t actually that hooked up look good in Barcelona when they’ve had a load of downforce put on them, but will then struggle at more ‘normal’ circuits, which will highlight the car’s inherent weaknesses.
Secondly, tyres have a major impact on times, and not every team runs the softest ones. It's worth noting that Lewis Hamilton claimed his fifth championship in 2018, and yet he was Mercedes’ fastest runner across all the days of last year’s winter testing... in eighth place!