A comprehensive guide to Formula One's preseason testing

Hamilton shrugs off Verstappen's comments at Mercedes launch (1:24)

Lewis Hamilton speaks about Max Verstappen's comments as the 2020 Mercedes car is revealed fo the first time. (1:24)

With the excitement of launch week behind us, it's time for F1's teams to get down to the serious business of pre-season testing, which starts on Wednesday, Feb. 19. Over the next two weeks, all 10 teams will take part in two three-day tests at the Circuit de Catalunya (a total of 48 hours of track time) to get to know their new cars.

The main objective for all of them is to be as well prepared as possible for the Australian Grand Prix on March 15, but for those watching on it also provides an opportunity to speculate on who's hot and who's not.

The testing timesheets can be notoriously misleading, but the aim of this guide is to allow you to know what to look for over the coming days.

How much should we read into testing?

Times in testing have the potential to be very misleading. Last year Ferrari left Barcelona as the clear favourite based on the data we had, but the Italian team arrived in Melbourne to find its car 0.7s off the pace of Mercedes.

Of course, that's not always the case. Sometimes it's abundantly clear when a team is struggling and sometimes it becomes very apparent when another has a big advantage. The key thing to remember is that headline times only tell a part of the story.

There are some key factors to take into account when reading the lap times:

  • Tyre compounds: The full range of F1's five tyre compounds are available during testing and, as a general rule, the softer the rubber the faster the car goes. Pirelli's tyres are unchanged from 2019, making comparisons between compounds easier than normal. There are five compounds on offer -- named C1, C2, C3, C4 and C5 -- and the higher the number, the softer the rubber. Last year, the gap between each compound was estimated to be between 0.6s-0.7s by Pirelli, although individual teams saw quite different gaps depending on how their car interacted with the tyres and the track conditions.

  • Fuel loads: The most impressive lap times in testing are often disguised by teams running with a few extra kilos of fuel in the tank. This is often referred to as sandbagging - a term that suggests teams are trying to hide their pace - but it is often down to the engineers trying to find a sensible baseline on which to work through setup changes. As little as 10kg of fuel can add 0.4s to a car's lap time at the Circuit de Catalunya, and from the outside there is no way of knowing how much fuel a car has on board at any one time. It is also not unheard of for struggling teams to run on vapours in the hope of making their situation look better than it really is.

  • Qualifying sims: Qualifying-style laps are also easy to spot as the cars will alternate between one 'hot lap' and one cooldown lap, which is necessary to let the tyres recover and to recharge the hybrid system for full deployment on the next 'hot lap'. But, as mentioned above, fuel loads are the big unknown and it is rare that a top teams will run with low fuel and their top engine modes in testing. Such is the secrecy of testing that some drivers have been known to back off just before the line so as not to reveal the 'true' pace of the car.

  • Race sims: One way of removing the uncertainty over fuel loads is to look out for teams attempting 'race simulations', which usually occur in the second week of testing. Typically, each driver will aim to complete at least one race simulation before going to Australia and these can be easily spotted by a pit board counting down from 66 laps (the length of a race at the Circuit de Catalunya) when they are on track. In order to complete a race distance without returning to the garage, the car will need to start the run with close to the maximum fuel load of 110kg, which is useful for analysing pace as it removes the question of whether they are running heavy or light. By working out an average lap time - removing anomalies caused by traffic or red flags from the 66 laps - it's possible to get a better indication of how quick a car really is.

  • Time of day: The Circuit de Catalunya in February sees quite big changes in temperature that can impact on lap times. The temperature in the mornings is sometimes in single figures, but by lunchtime it can be nudging 20C. The fastest laps are often recorded just before the lunch break when the conditions are at their best and the tyres can be brought up to the optimum temperature more easily. However, comparing a lunch-time lap on day one of a test with a lunch-time lap on day three is also rarely a fair comparison as the rubber laid on track by the car improves track conditions from day to day.

  • GPS traces: The most useful tool to spot the fastest cars in testing isn't available to fans and the media. However, teams closely monitor the GPS traces of rival cars to gather data on both corner speeds and straight-line speed. The GPS data can indicate strengths or weaknesses of a car in either slow- or high-speed corners (the Circuit de Catalunya has a mix of both), which can also offer an indication of which cars will be quick at which circuits. The speed at which a car accelerates and brakes is also useful to guesstimate engine modes and fuel loads.

What are the teams trying to achieve?

While teams do pay attention to each other, their main focus is on themselves. The opening day of testing is typically filled with system checks and monitoring cooling levels to make sure the car is able to run reliably. Despite cool ambient temperatures at pre-season testing, teams will try to get a gauge of how much margin they have so that they can run the car at its optimum performance without overheating. This data will also inform how aggressive future upgrades can be later in the season.

The early days of testing are also a good opportunity to make sure that the car's behaviour on track matches up with wind tunnel performance and CFD simulations back at the factory. The cars are often fitted with aerodynamic rakes (a collection of pitot tubes on a metal structure that measure air pressure) to check how the aerodynamics are performing at various parts of the car.

Once any gremlins have been flushed out and a baseline has been set, teams run through setup changes to see how the car adapts to different settings. A good car is one that reacts predictably when setup changes are made, allowing the engineers to develop ways of adapting the car to the needs of the driver at any given circuit.

Understanding how to get the best from the tyres is also a key focus in testing. Some teams opt to work their way through the range of compounds, while others focus on the same compound with different setups and extrapolate their findings. Mercedes has typically adopted the latter approach, but there are pluses and minuses to both.

By the end of the second week, most teams will hope to complete at least one race simulation and also have a gauge of how the car performs on a qualifying-style run. Updates often come for the second test and teams start to define what their Australia race package will look like It's then a case of crunching all the numbers ahead of the first race to arrive in Melbourne with the fastest car possible.

Is this the first time the cars have hit the track?

At the time of writing, Red Bull, Mercedes, Alfa Romeo, Alpha Tauri, Renault, Williams, Haas and McLaren had all completed 100km of running with their new cars at filming days. Teams are allowed to complete two filming days per year, which are the only additional track running permitted on top of official testing and race weekends. Aside from the restriction on mileage, the cars also have to run on special tyres that do not offer the same level of grip as the race tyres, ruling out any serious performance work. However, at this stage of the season it offers a chance to check cooling data and flush out any gremlins in the system before official testing gets underway.

In addition to the filming day, the top teams will have completed thousands of virtual miles on test benches back at their factories. Not all teams have such facilities on site, but the likes of Mercedes, Ferrari and Red BUll often discover cooling issues or drivetrain issues during these tests, which typically start a month before pre-season testing gets underway. Suspension components are also tested on special rigs that simulate the bumps and kerb strikes a car experiences on any given track as well as the downforce loads created by the car itself.

Are there any rules?

With the exception of passing crash tests prior to running, there are no real rules governing the cars during testing. There is no scrutineering and teams could, in theory, test parts that are illegal under the regulations (although there would be little advantage to gain by doing so). In 2013, Caterham and Williams ran small bits of bodywork to divert exhaust gasses towards the diffuser which would have been illegal under the regulations but allowed them to gain a greater understanding of the sensitive area in testing.

One new rule for this year is an open-door policy on team garages. While that doesn't mean anyone can wander in from the pit lane, it prevents the teams from hiding behind screens while they work on their cars. The only exceptions are if the floor of the car is removed or if the car has come back to the pits following an accident.

Some teams are known for trying to trick one another and divert attention from novel design features. In 2010, Red Bull ran stickers that looked like exhaust outlets on the top of its car to try and divert attention from the actual exhaust, which was being used to boost the performance of the diffuser. Red Bull also caused headlines when it ran a dazzle camouflage livery on its 2015 car, with the aim of making it harder for rival teams to see aerodynamic detailing on the car.