The heat is on…

Temperature, or rather the lack of it, was certainly on the minds of many of the record crowd who attended the recent British Grand Prix at Silverstone.

Silverstone is often one of the cooler Grands Prix visited during the course of the season and the temperatures experienced at a track do not only have an affect on the clothing worn by the spectators.

Every Formula One tyre has its optimum temperature operating range, and ensuring that the tyres are in this range is something that teams and drivers are very mindful of as they attempt to extract the best performance from the two tyres that Bridgestone allocates to each race.

Bridgestone Motorsport Chief Engineer Jun Matsuzaki gives an insight into some of the considerations around the topic of temperature and how it affects Bridgestone’s tyres and Formula 1 car performance.

“There are many factors involved in getting a tyre into its temperature working range,” explains Matsuzaki.

“Tyre temperature working range considerations have been more noticeable this season as we have usually brought tyres to races with different temperature working ranges. From this year’s Formula One tyres, our hard and medium compounds are from our higher working range family, and our soft and super soft are from our lower working range family.

“What this means in practical terms is that one tyre generally delivers its best performance sooner than the other, as it gets to its best temperature quicker.

“When a tyre is at the correct temperature it gives its best grip and performance and factors such as graining, wear and degradation are affected by how hot the tyre becomes. Being too hot or not hot enough are both detrimental to getting the best performance. 

“It’s not just the air and track temperatures that are important, temperature is created within the tyres themselves as they are used.

“The circuit layout, the roughness of the track surface, the aerodynamics and suspension of the car and the driving style of the driver are all crucial aspects in heat generation.

“The circuit layout helps determine the amount of forces that go through a tyre. For example, turn 8 at Istanbul is a corner which lasts for around seven seconds with high G-forces and this corner generates a lot of energy in the tyre, which causes the tyre to get hot.

“The roughness of a circuit plays a part too. A rougher surface is more abrasive and this means that more energy goes through the tyres, and more heat is generated, or a very smooth surface can mean that the tyres are sliding a lot, and this generates heat too.

“A car’s aerodynamics is important as the downforce created affects the amount of applied load on the tyres. Put simply, the more applied load, the easier it is to get temperature into the tyres, especially in cold conditions. If a car creates more downforce than another then it has an advantage in cold conditions as it works the tyres better and creates more heat to keep them in their temperature working range.

“Downforce is good, even in hot weather conditions, as a good level of downforce from a car means a good contact patch between the tyre and road and therefore the tyres are working properly. If there is less downforce in hot conditions then the car can slide and this generates less controlled heat in the tyres.

“The heat generated in the tyres as a result of good levels of downforce is generally quite consistent, however heat generated from a car sliding in hot conditions generally keeps increasing and is not good for tyre performance consistency.

“There is also the area of suspension design and in particular the dynamic camber geometry through a corner. A design which puts more stress on the inside edge of the tyre will generate more heat, and this could be useful in cold conditions. However, this same design would not be so advantageous when the weather conditions become warmer.

“The overall roll balance of a car is important too. If a car has a stiff overall roll balance it will place more stress on the outside tyres, which will help with warm-up. However this will not be such a good situation when the conditions are hot as too much heat than is wanted could be created.

“Temperature is also an important factor for inner pressure management. Tyre performance is affected by different tyre pressures and pressure changes with temperature change so managing tyre temperature is very important for this reason too.

“When in the pits and before the start of the race, the tyres are warmed by tyre blankets and rim heaters, but once on track it’s the driver who has the most direct influence on tyre temperature.

“Before the start of a race, the driver needs to maintain heat in the tyres during the formation lap, then during the race he needs to ensure the tyre is working at its optimum temperature as much as possible.

“If the other factors mean that conditions tend towards the tyre being too cold, then an aggressive driving style can assist heat generation. If the other factors mean that conditions tend towards the tyre becoming too hot, then a forgiving driving style can minimise unwanted heat generation.

“There are many factors involved, but the competitors who ensure that their tyres are always at the best temperature usually get good results.” 

Source - Bridgestone Motorsport 

Image (c) Bridgestone Corporation

Read original blog post