F1 terms explained: what box, marbles, DRS, undercut and more mean

Watch any grand prix and you'll notice a vast array of jargon being used by drivers, race engineers and commentators. Even avid fans can have trouble understanding all of F1's technical terms

F1 terms explained: what box, marbles, DRS, undercut and more mean

It's a result of the complex engineering that goes into building a Formula 1 car, as well as the depth of knowledge that teams develop to extract as much performance as possible over a race weekend.

The sport has taken steps in recent years to try and make things easier for fans, such as simplifying the names of the tyre compounds provided by Pirelli.

Even so there are still plenty of expressions that can confuse casual viewers, and in the worst cases put them off watching altogether.

A little understanding goes a long way, so this glossary of common phrases should bring you right up to speed with F1's technical terms.

Blue flag

Blue flags are shown to drivers who are about to be lapped. After being shown a blue flag, drivers must get out of the way of faster cars at the earliest opportunity, or face a time penalty for not responding quickly enough. Blue flags are used to prevent the lead cars being held and interfering with the result of the race.


When a driver is told to 'box, box', they're being instructed to make a pitstop. This is because 'box' sounds more distinct than 'pit' over the team radio, so there's less chance of confusion leading to an error. The word itself refers to the painted box outside a team's garage where pit stops take place, although some argue that it hails from 'boxenstopp', which is German for 'pit stop'.


Blistering can happen when a tyre gets too hot. This can cause the rubber to soften and break apart more easily, leading to a loss of grip and performance. Blistering can affect the whole surface area of a tyre, or sometimes just a thin strip that looks like an unbroken line when seen from the on-board camera.

Drivers want to avoid blistering because it lowers the amount of grip a tyre can produce, and once a blister appears it can be almost impossible to get rid of. That in turn means that drivers have to slow down even more to avoid making the blisters worse. In the past, blisters have led to complete tyre failures, which are particularly dangerous at high speed.

Brake balance/bias

F1 cars have a brake on each wheel, but drivers can choose how much braking force is applied to the fronts and rears depending on the needs of any given corner. They do this by operating the controls on their steering wheel, often making several adjustments per lap. It's usually referred to in terms of moving the brake balance (or bias) forwards or backwards.

Perfecting the brake balance is key to getting an F1 car to slow down and corner. If you apply too much bias to the front the car will struggle to turn, but adding too much to the rear could result in a spin. Drivers have to manage this challenge throughout each race, making adjustments for changing levels of grip and the reduced weight of the car as it burns off fuel.

Cold tyres

Each tyre compound used in F1 has a temperature window in which it works best and delivers the most grip, so if a driver can't get the tyres up into this window, they're said to be too cold. Cold tyres are to F1 cars what Kryptonite is to Superman: when tyres are cold, they can't produce anywhere enough adhesion to deal with the speeds and cornering forces typical in the sport. It's why you see drivers weaving around on formation laps; to increase the amount of heat in the tyres prior to the start of the race.


Not all F1 tyres are the same: Pirelli supplies five different compounds of tyre (picking three for each grand prix) as well as an intermediate tyre for damp conditions and a wet tyre for when it's raining. The compounds contain different mixes of rubber, polymer, sulphur and various other ingredients. Generally speaking, the softer a compound is the faster it will be over a single lap, but the less durable it will be too.


Degradation refers to the reduction of grip caused by a tyre getting too hot. If you hear drivers talk of not getting their tyres 'in the window', they mean they haven't been able to drive the car in such a way that the compound stays in its ideal operating temperature where maximum grip is delivered.

Degradation (or sometimes deg) is not to be confused with wear, which is the process of the tyre tread thinning over time due to friction in the track surface.

Dirty air

The faster an F1 car goes, the more turbulent the aerodynamic wake it leaves behind it. Following in a car's dirty air is tricky for two reasons: firstly the unsettled air can reduce downforce, which means drivers have to corner more slowly. Secondly, it can cause tyres and brakes to overheat, forcing drivers to back off. Dirty air is one of the main reasons why overtaking is so hard at some F1 circuits.

New rules - originally due in 2021 but now delayed until 2022 - should force teams to build cars that produce far less dirty air. In theory this will make it easier to follow during races, leading to more exciting racing.

Dirty air is the opposite of clean air, which a car runs in when there's nothing ahead of it.

Double stacking

Double stacking is when a team pits both of its cars on the same lap, with one following the other into the pit lane. Ideally the second car will be far enough behind that it pulls into the pit box just as the first car is leaving, and each pit crew is heavily drilled for such a scenario.

Teams usually double stack their cars in response to a safety car, although there are other situations that cause them. Double stacking is notoriously tricky: a botched double stack cost Mercedes victory at the 2020 Sakhir Grand Prix after a late call confused the team's pit crew.


Downforce is the aerodynamic effect that pushes F1 cars towards the ground when they move forwards. The higher a car's downforce, the more grip it will have in corners, the more traction it will have and the easier it will be to generate heat in the tyres. The key to a fast F1 car is to create downforce without also developing drag, which is the aerodynamic resistance acting against the forward momentum of the car.


DRS is short for Drag Reduction System, which is a movable flap on the rear wing of an F1 car. Opening the flap reduces aerodynamic drag, making it easier for a car to accelerate and increasing its top speed.

The DRS is an overtaking aid, but drivers can only use it in designated DRS zones that are set before the start of a race weekend. Most tracks have one DRS zone, although some have two. The DRS can only be used once a driver has closed to within a second of the car ahead at a specified 'detection point' on the circuit.

The DRS was introduced in 2011 to make overtaking easier, and while some see it as an essential weapon in a driver's arsenal, others believe it makes racing artificial.


ERS are an F1 car's Energy Recovery Systems. These harvest electrical energy over the course of a lap, giving drivers a power boost that can be used to attack or defend during a grand prix. The ERS can generate an extra 160hp for around half a minute per lap.

Two components form the ERS: the Motor Generator Unit - Heat (MGU-H) and Motor Generator Unit - Kinetic (MGU-K). The MGU-H recycles waste heat from the turbocharger, while the MGU-K recovers lost energy from the braking system. The electricity produced is kept in the Energy Store (ES); usually a battery made up of lithium-ion cells.

Flat spot

If a driver locks up a tyre when braking, it can sometimes cause the contact patch of the compound to become flat instead of round. This reduces grip and can also cause severe vibrations that make an F1 car more difficult to handle. In some cases the vibrations are so extreme that the front wing can be shaken clean off, as happened to Sebastian Vettel's Ferrari at the Bahrain Grand Prix in 2019.

Formation lap

The entire F1 field completes a slow formation lap (or warm-up lap) ahead of every grand prix, and before every race restart that follows a red flag stoppage. This gives engineers and mechanics time to clear the grid, and also allows drivers to warm up the tyres and brakes so they're not unsafe for what is the most dangerous part of the race.


Graining occurs when chunks of rubber break off from a car's tyres, but instead of being thrown to the side of the track the loose material then sticks to the tyre itself. This makes the surface of the tyre uneven and reduces the amount of grip it can produce. It's possible for a tyre to quickly recover from graining if the driver makes changes to their driving style.


The halo is the carbonfibre frame that surrounds the cockpit of every F1 car. It's a mandatory, standardised component that's designed to protect a driver's head from flying debris and impacts from other cars.

The halo was introduced in 2018, four years after the incident which killed Marussia driver and Ferrari protege Jules Bianchi. Although the halo would not have saved the Frenchman's life, it has been credited with vital interventions since, most notably protecting Charles Leclerc at the Belgian Grand Prix in 2018 and helping Romain Grosjean survive a 137mph crash at the Bahrain Grand Prix in 2020.


A driver's headrest is made from an energy-absorbing foam, and is designed to absorb impact forces in the event of a crash. The headrest slots into the top of the cockpit like a jigsaw puzzle piece.


A lock-up is when a driver brakes so hard that one or more wheels starts to under-rotate, or stops rotating altogether. This often leads to a puff of white smoke from the tyres, and can result in flat spots that force a driver to pit for fresh rubber.


When tyres wear over the course of a grand prix, rubber is thrown off the cars and accumulates on the sides of the track. These chunks are called 'marbles', and drivers do their best to avoid them during the race. This is because they have the effect of making parts of the track slippery, but they also cause the same problems as graining.

However, after a race has finished you'll often see drivers deliberately drive over the marbles to pick up the discarded rubber: this adds weight and makes it less likely that a car will be disqualified for being underweight when it is weighed after the race.


The Motor Generator Unit - Heat (MGU-H) forms part of an F1 car's Energy Recovery Systems (ERS). It takes heat energy that would otherwise be lost from the car's turbocharger and converts it into electricity, which can then be used to boost performance during the grand prix.


The Motor Generator Unit - Kinetic (MGU-K) is the second main component of the ERS. It harvests energy lost during braking and turns it into electricity, which is then sent to the Energy Store (ES) to be redeployed later on.


Oversteer occurs when a car turns into a corner, only for the rear end to try and continue in a straight line. This results in a skid (or 'a snap of oversteer'), and drivers usually have to apply opposite lock (turning the wheel into the direction of the slide) in order to correct the problem.

Parc ferme

Parc ferme is French for 'closed park', and refers to the area sectioned off by the FIA for scrutineering. This is when scrutineers check that all cars are compliant with the rules, and teams are not allowed to touch their machinery in this time unless strictly supervised.

Meanwhile, parc ferme conditions apply from the moment a car leaves the garage for qualifying until the cars are released by scrutineers after the grand prix is over. When not physically sat in parc ferme teams are restricted to making only a handful of changes, including things like filling the fuel tank and making minor alterations to the front wing.

Pit window

The pit window is one of F1's stranger terms, as it involves a certain amount of guesswork about when a driver will make a pit stop based on the expected lifespan of the tyre compound on the car. Pirelli usually estimates how far it thinks its tyres can go, and teams factor this information into their qualifying and race strategies. Meanwhile, broadcasters can use the information to predict when a driver will stop. So when the pit window is 'open' it means a driver is expected to make a pit stop soon, although it doesn't account for how good a driver is as looking after the tyres or various other factors.

Racing line

Theoretically, the racing line is the fastest path around a race track. Generally speaking it uses the full width of the circuit and intersects the apex of most corners in order to open up the radius of each turn and maintain as much speed as possible. Drivers often experiment with their racing line during practice in order to work out how to achieve the quickest lap times, and it can evolve depending on the weather conditions and how much grip is being provided by the track surface.


Rake describes the ride height at the rear of a car compared to at the front of the car. Lifting the rear above the level of the front can create space under the floor to help a car's diffuser perform better, and it can also increase the downforce provided by the surfaces on top. However, it can also make the aerodynamics more difficult to control, and it becomes much harder to stop the nose of the car scraping against the surface of the track. Red Bull is the most notable purveyor of the 'high-rake concept', using an aggressive set-up in this regard in recent seasons.

Red flag

The red flag is used to bring a grand prix to a halt in the event that stewards decide doing so is necessary for the safety of the drivers. Red flags are most common after heavy crashes where stricken cars can't be recovered safely or when debris is scattered across the track, although they can also be brought out if wet weather becomes so treacherous that a circuit becomes undrivable.


F1 tracks are broken up into sectors to help viewers and teams understand where the cars are quickest. Fans will be familiar with Sector 1, Sector 2 and Sector 3, although the teams have access to much smaller 'mini sectors' so they can really pinpoint where their cars are delivering and where they're underperforming.

F1 sectors roughly resemble thirds of a track, although there's no set distance they have to be. On the official timing board visible to teams and commentators, a driver's sector times are listed alongside their lap times: the timing board is colour coded, so if a driver sets a 'purple sector' it means they've gone fastest of anyone in that sector and that particular session. A 'green sector' indicates a personal best, and yellow means a driver is slower than their personal best.


The faster an F1 car goes, the more it has to work to punch through the air. By doing so it leaves a pocket of low-pressure air behind it, and any car following behind doesn't have to work as hard to achieve the same acceleration. Getting into this pocket is known as slipstreaming, and drivers will often do this to generate excess speed that can then be used to overtake.

Slipstreaming is sometimes referred to as 'getting a tow', or 'distant tow'. At certain tracks teammates take turns being the lead driver in qualifying, giving the car behind an advantage that can sometimes be worth several tenths of a second. At circuits like Monza and the Red Bull Ring, it's not uncommon to see drivers slow down to a crawl in order to benefit from rather than give a tow to the rest of the pack.

Tyres: Soft, Medium, Hard

F1 tyres are supplied by Pirelli, which provides five different compounds in addition to the wet tyres (for when it's raining) and intermediate tyres (for when a track is damp, but neither wholly wet nor dry). These range from the most durable C1 compound through to the least durable C5: Pirelli nominates three compounds for each race weekend, but teams can choose how many sets they want of each type.

To make things easier for fans, the compounds are always referred to as 'soft', 'medium' and 'hard' regardless of the compound mix being used. They're identified with red, yellow and white colour schemes on the sidewalls of the tyres respectively.

Wet tyres are blue and have deep grooves to clear water; intermediate tyres are green and have shallower grooves. Meanwhile, dry-weather tyres have no grooves at all and as such are often called 'slicks'.


The undercut effect is often used by teams as a strategic overtaking method. By pitting for fresh tyres first, a driver can make use of the extra grip immediately and quickly close the gap to the car ahead. If the lead car doesn't react in time - or can't match the pace set by those behind it on faster tyres - it will be at risk of losing positions when it eventually makes a pitstop.

It's not always the case that new tyres will outperform old tyres, as on some tracks it takes a while to heat up new rubber. In that scenario the best strategy is to pit after rivals, and this is called the overcut.


The opposite to oversteer, understeer is when the rear of a car has the grip to turn into a corner but the front does not. This causes it to slide wide, taking the driver off their preferred line. As tyres wear over the duration of a grand prix, cars tend to develop more understeer as grip decreases. Drivers will sometimes describe understeer by saying their car doesn't want to 'turn in'.

Podcast: Why McLaren can become an F1 force again

Previous article

Podcast: Why McLaren can become an F1 force again

Next article

Formula 1 commission to discuss calendar, engine freeze and sprint races

Formula 1 commission to discuss calendar, engine freeze and sprint races
Load comments

About this article

Series Formula 1
Author Joe Holding
The clues Hamilton’s F1 contract afterthought gives to his future Plus

The clues Hamilton’s F1 contract afterthought gives to his future

The Formula 1 world reacted with surprise when it learned Lewis Hamilton’s long-awaited new Mercedes deal guarantees his presence on the grid only until the end of 2021. Both parties claimed publicly they were happy with the arrangement but, asks MARK GALLAGHER, is there more to it than that?

How a harshly ejected Red Bull star has been hooked by racing again Plus

How a harshly ejected Red Bull star has been hooked by racing again

Driver-turned-DJ Jaime Alguersuari lost his love for motorsport when he was booted out of Formula 1 just as he was starting to polish his rough edges. Having drifted from category to category then turned his back on racing altogether in 2015, he’s come full circle and is planning a return in karts for fun

Why Mercedes isn't confident it's really ahead of Red Bull at Imola Plus

Why Mercedes isn't confident it's really ahead of Red Bull at Imola

While Mercedes struck back against Red Bull by topping the times at Imola on Friday ahead of the Emilia Romagna Grand Prix, the overall picture remains incredibly close. Despite having a possible edge this weekend, the reigning Formula 1 world champion squad is not taking anything for granted...

Formula 1
Apr 16, 2021
What Mercedes must do to keep its F1 title challenge on track Plus

What Mercedes must do to keep its F1 title challenge on track

Mercedes may find itself leading the drivers' and constructors' standings after Lewis Hamilton's victory in the Bahrain Grand Prix, but it is well-aware that it came against the odds, with Red Bull clearly ahead on pace. Here's what the Brackley team must do to avoid its crown slipping

Formula 1
Apr 16, 2021
Why Tsunoda can become Japan’s greatest F1 talent Plus

Why Tsunoda can become Japan’s greatest F1 talent

While Japan's fever for motor racing is well-documented, the country has yet to produce a Formula 1 superstar – but that could be about to change, says BEN EDWARDS

Formula 1
Apr 15, 2021
Why the demise of F1's hypocritical spending habit is cause for celebration Plus

Why the demise of F1's hypocritical spending habit is cause for celebration

For too long, F1's richest teams have justified being able to spend as much as they want because that's the way they've always conducted their business. STUART CODLING says that's no reason not to kick a bad habit

Formula 1
Apr 14, 2021
The double whammy that is defining Vettel’s F1 fate Plus

The double whammy that is defining Vettel’s F1 fate

It's been a tough start to Sebastian Vettel's Aston Martin F1 career, with a lack of pre-season testing mileage followed by an incident-packed Bahrain GP. But two key underlying factors mean a turnaround is not guaranteed

Formula 1
Apr 14, 2021
The diva that stole a march on F1’s wide-bodied opposition Plus

The diva that stole a march on F1’s wide-bodied opposition

In 2017 new F1 technical regulations were supposed to add drama - and peg Mercedes back. STUART CODLING looks at the car which, while troubled, set the stage for the wide-bodied Formula 1 era

Formula 1
Apr 13, 2021