Tire deg or tire degradation is a common term used in Formula 1, and you might hear drivers complain about it or commentators discuss it many times during a race. It’s an incredibly important aspect of F1, and so teams are constantly monitoring their tire degradation.
Deg or degradation in F1 refers to the thermal performance loss of a car’s tires. It’s a measure of how fast the tire is losing performance, both as a result of track conditions and how the car is being driven. It’s not the same as tire wear, which is the tire physically wearing out.
It’s important to understand exactly what tire deg is and how it affects the performance of the tires. This will help you better understand what is happening over the course of a lap and during the race. I go through tire deg in more detail below, and draw particular attention to the differences between deg and wear.
An Overview Of Tire Degradation In Formula 1
An F1 tire (and any race tire for that matter) goes through various heat cycles during a race or qualifying session. For example, the driver will warm the tires up by weaving around on out laps and formation laps, and then they’ll push the car to the limit on their flying laps, driving the temperatures even higher.
Then they might ease off to manage their tires, resulting in them cooling down again, before doing more push laps, which once again raise the temperatures. This happens during practice, qualifying, and the race, with safety cars during the race being another factor that can affect how hot the tires are (as drivers must go slower behind the safety car, dropping their tire temperatures).
What Heat Cycles Do To Tires
Generally, a tire becomes harder after each heat cycle. Experienced drivers take good care of their tires and try not to let them build up too much heat. A more evenly heated tire goes through fewer heat cycles and maintains its optimal grip for a longer time.
Also, new racing tires, unlike the tires you’d find on a normal road car, are not fully cured when they come out the factory. Because of the extreme heat to which the race tire is exposed, tire manufacturers (in F1’s case it’s Pirelli) leave parts of the curing process to the drivers. If a fully cured tire were taken to the track, the tire would be much harder from the start, leading to less grip and longer lap times.
Tire engineers understand that heat changes the rubber compound of the tire, and so they plan ahead for part of the curing process to take place on the track. This is one of many reasons race tires are much softer than normal tires, and the driver has the task of controlling how much the tires cure or stay in an optimal grip range.
Tire Temperatures Are Very Important
So, tire temperatures are obviously crucial in Formula 1, and they can have a huge impact on how fast the car can go. This means tire deg in particular is a vital thing teams must measure over the course of a race, as it is specifically related to the thermal performance of the tires.
Some cars are able to get heat into their tires quickly, which will help them over qualifying laps. However, this may become a problem in the race if the tires keep building up their temperature. Tires that are too hot will also lose performance.
The Importance Of Tire Temperature
When a tire is too cold or too hot it is not able to produce optimal grip for the car. This means that the driver may struggle to keep the car under control. Drivers might experience spinning, sliding, tires losing traction when accelerating, or in some cases they may struggle to slow the car down under braking.
So, building temperature is important to ensure the tires have enough heat in them to provide enough grip, but not so much heat that they overheat and lose grip. This balance of temperature is linked to the thermal performance of the tire, which is where the term tire deg or tire degradation comes in.
KEY POINTS• Tire temperatures are very important in Formula 1 (and all kinds of motor racing)
• The tires go through various heat cycles during a session on track
• Tire temperatures are strongly linked to tire performance
What Is The Difference Between Tire Degradation & Tire Wear?
While many might think that tire deg and tire wear are the same thing, there’s actually a big difference between the two terms. It’s important to grasp this difference, as teams, drivers, and commentators might refer to one or the other as being a problem for a specific car.
While tire deg is the thermal performance loss of the tire, tire wear refers to the lifespan of the tire and how much of it has been consumed. A tire physically wears as it is being used, and with excessive wear drivers may experience blistering or graining.
Storing Heat In The Tire
But these effects are related to the temperatures of the tire, and the differences between the temperature of the tread (the bit that touches the track) and the temperature inside the tire. But the thickness of the tread, which naturally decreases during the race because of wear, also plays an important role here.
The thicker the tread, the more heat can be stored in the tire, and the thinner the tread, the less heat can be stored. The tread can become so thin to the point that it no longer ‘hold’ the necessary heat in the tire. So, tire wear ultimately determines how much heat can be stored in the tread.
While tire wear is purely about how the tire wears physically, tire degradation is purely about thermal performance and its effect on the tire. Over time, an F1 car’s tires will begin to physically deform at the molecular level.
What F1 Tires Are Made Of
A Formula 1 tire primarily consists of rubber. But the rubber used in the tire-manufacturing process is actually composed of a blend of polymers. These are long chains of molecules that spontaneously adopt a spherical form and knit themselves together. Sulphur is added, and through a baking process, numerous sulphur bonds are generated between the polymer chains.
With selected polymers (like polyisoprene, polybutadiene, and butadiene styrene), the viscosity varies as a result of the number of sulphur bonds generated during the vulcanization process. So, the final compound might be relatively soft (with a lower ‘modulus’ – a coefficient that reflects a particular substance’s specific properties) or relatively hard (with a higher modulus).
These compounds used in the tires begin to change shape on a molecular level, some temporarily and some permanently, under the extremes of temperature. The process of deforming and reforming is known in F1 as the tire’s heat cycle, which we discussed at the start of this article.
How This Relates To Tire Deg
This is a natural part of racing at high speeds, and it’s not exclusive to Formula 1. However, the Pirelli tires used in F1 are specifically designed to degrade over time to force teams to respond to this using strategic pit stops. Tire deg is essentially a measurement of how much grip the tire loses because of thermal stress, while tire wear is how much of the physical tire itself has worn away.
Tire deg has a significant effect on the levels of tire wear. When a tire begins to overheat, not only will the driver begin to lose grip from their tires as a result of the tire compounds becoming less ‘sticky,’ but the tires will also begin to wear out much faster than before.
As we already discussed, racing tires must not be fully cured straight out of the factory, and they will go through heat cycles over the course of a session on track. If they get too hot in the process and are not kept within the optimum temperature window, the tires vulcanize more strongly after the heat cycle and therefore lose grip.
This means that there will be less overall life in the tire, so it will not be able to last as long, and it will also mean that the tires have less of their physical structure left to provide grip. So, with high levels of tire degradation also come high levels of tire wear, and both lead to a decrease in grip for the driver.
KEY POINTS• Tire wear and tire degradation are two different concepts
• Tire wear is a measure of how much the tire wears out physically
• Tire deg is a measure of the tire’s performance loss due to thermal stress
How Fast Do F1 Tires Degrade?
Formula 1 tires can degrade extremely fast. They can degrade a lot even over the course of just one lap. How fast F1 tires degrade depends on the driving style of the particular driver, the track conditions, and the compound of tire the car is using. Soft tires degrade faster than hard tires.
The car’s setup also has an influence over how fast the tires will degrade. Springs, dampers, camber, toe, and tire pressure all influence tire degradation, as well as weight distribution, balance, centre of gravity, the aerodynamics of the car, lateral and horizontal load transfer, and even the differential setup and engine settings.
Another factor is the stiffness of the suspension system. If this is not designed or set up correctly, a car can have high tire degradation. Cornering stiffness is another factor, and so it must be noted that virtually everything about an F1 car has an impact on degradation, which makes the complexity and importance of excelling in this discipline clear if a team wants to succeed.
Lasting One Lap
In modern Formula 1 cars, the tires can sometimes degrade by the end of the lap if they are pushed too hard. This is especially true in qualifying sessions, as drivers will push their cars far harder than they would push in a race.
There’s also a wide range of tire deg across the cars during the race. Some cars are able to get heat into their tires quickly, which will give them quick opening laps and out laps after a pit stop. Other cars might struggle with overheating tires and need to slow down more in order to cool the tires down to avoid excessive degradation.
What Does Falling Off The Cliff Mean In F1?
Falling off the cliff in F1 refers to a car’s tires losing lots of their grip very quickly, leaving the driver with very little grip all of a sudden. This happens towards the end of a tire’s lifespan, usually forcing the driver to pit. Falling off the cliff leads to longer lap times.
High Deg vs Low Deg F1 Tracks
Above are examples of high and low deg tracks in F1, but note that there is not necessarily a straightforward way of measuring or distinguishing between high and low. At many tracks it is highly dependent on the conditions. For example, Australia can be fairly low deg on the medium and hard tires on a cooler day with some deg on the softs, but hot days may lead to more deg on all tire compounds.
One of the most influential factors to consider when it comes to the degradation of F1 tires is the condition of the circuit that the cars are driving on. Some circuits are worse for tires deg than others, and there are some key differences between these circuits that cause the variance in tire deg.
Each circuit is unique, and teams can combat high tire deg by adjusting their setup. The team can adjust the camber and toe for example, or alter the car’s downforce levels.
Choosing The Right Tires
Pirelli also carefully considers many factors when deciding which tires to bring to each track. The characteristics they consider include the roughness of the asphalt, the available grip level, the track layout (and how this affects the load put through the tires), along with the anticipated weather and how the tires have worn and degraded in previous years at the track.
Tracks with lower deg levels generally allow them to bring softer tires, and tracks with higher deg require them to bring harder compound tires. This helps the teams to cope better with the track conditions.
Drivers will have the soft, medium, and hard tires available to them at each track. However, the compound of each of these tires can vary. There is a range of six different tires that Pirelli can bring to each track, namely the C0, C1, C2, C3, C4, and C5 tires. The hardest compound on the list is the C0 tire and the softest compound is the C5 tire.
Soft tires will wear faster than harder tires, but they won’t necessarily degrade faster. This is especially true if a driver can keep their tires within the ideal operating window, or if the car naturally shows little degradation (like the Red Bull cars in 2022). The ideal temperature windows range from 85-105°C for the softest tire (185-220°F) to 120-145°C for the hardest compound (250-290°F).
Track Factors That Influence Tire Deg In Formula 1
The track temperature might be the most obvious factor that will affect the temperature of the tires. In hotter climates, such as in the Middle East, the track temperature can become very high during the day, which can cause the tires to overheat quicker.
In cooler climates, such as during the European races, the track temperature can drop significantly over the course of a race. This is when drivers can begin to struggle to control the temperature of their tires and tend to take longer to get them into their ideal operating window.
The track surface is another important factor that can influence both tire deg and tire wear in F1. Each Formula 1 circuit is made of a different mixture of tarmac compounds. This gives each track a unique surface, which influences the tire temperatures.
Some circuits are more abrasive than others. This can be great for grip, as a circuit with more abrasive tarmac can lead to more friction between the tires and the surface of the track. However, this added friction will also cause the tires to heat up much faster, leading to high tire deg.
The higher tire deg then in turn leads to higher tire wear, but more abrasive surfaces also increase wear just by the fact they are quite rough. On abrasive circuits, Pirelli will often bring their hardest compound tires, as they will be able to provide enough grip while also being able to withstand the higher tire deg from the added friction.
KEY POINTS• The rate of tire degradation in F1 varies depending on lots of different factors
• Pirelli takes lots of things into consideration when choosing which tires to bring to each track
• A big factor that influences tire degradation is the setup and overall design of the car itself
Tire deg or tire degradation in F1 refers to the thermal performance loss of the tires, which is different to the physical wear of the tire. Tire deg is basically a measure of how much grip an F1 car’s tires can provide, and tire deg usually increases over time, which in turn increases tire wear.
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