02 August 2019 15:45
Tyres have become one of the true hotspots of all motorsports. Finding the perfect mix of grip and durability can make or break a race. Chris explains the different types of tyre used in different racing series, and the fine balance between grip and durability.
Whether attacking the apex on a circuit, racing through closed roads, or just popping down the shop for a pint of milk, the rubber on our tyres have become an intricate science. We constantly hear drivers and commentators referring to the different compounds, grip levels, degradation, and distribution of tread, but what do these terms all really mean?
Why is grip important? There are two main reasons. The first, is that grip allows cars to go faster around the corner without understeering off the circuit. The second, and equally important, is the transition of power from the wheel to the circuit. The more grip you have in the tyre, the less wheelspin and that means fewer horses (horsepower) get away!
The tyre is in many ways the most fragile part of the vehicle, so they are made up of several layers to support the structure. This includes an inner liner for strength, a carcass that holds the tyres shape, a breaker or belt that protects the carcass, and the rubber tread layer on top. There is also the tyre sidewall that keeps this all together. Between the pressure of the road, the wheel rim, and the internal air pressure; these tyres are built to last, or at least for 20 laps.
The slick tyre is the most common racing tyre in top level motorsports. There aren't any groves or patterns, giving maximum contact between the tyre and the race circuit, and teams also control the tyre pressure on each wheel to maximise this contact. The rubber of the tyres is specially formulated to offer a high level of grip based on the hire temperatures they reach; however, this also causes the surface to soften and break down.
This is why we have different compounds of tyre. Each compound will offer varied levels of grip and matching degradation. Using the softer tyre would have higher grip levels, but would use all it's surface rubber too quickly and the performance can suddenly fall off the metaphorical cliff, leading to timely pitstops, or worse, the tyre to burst. Using the hardest tyre would in turn need fewer pitstops, however not offer the same grip levels, sacrificing lap time.
Teams and drivers therefore trade durability vs. grip. For many races teams and drivers choose the same, but on occasion fortune varies the brave, and your ability to manage the ties, and make them last longer than they should becomes a very important skill. A great example seen with Lewis Hamilton in Monaco this year.
At the 2007 Chinese Grand Prix, Lewis Hamilton didn't get it so right. He took his tyres way past their use, running them down to the canvas. Whilst attempting to pit, he had no grip under breaking and the car slid into the gravel trap, retiring Lewis. This is likely the moment he lost the 2007 World Championship.
When visiting a circuit, I love nothing more than a sunny day to enjoy the racing. That said, rain is the great equaliser, and can really change the prospects of someone's race. Slick tyres just can't work in these situations, as they can't generate the amount enough heat to grip the track and the cars can career off as if driving on ice.
In these conditions, treaded tyres are ideal. The additional cut tread in the tyre allows for more targeted patches of grip, and the gaps allow the displacement of water. Our road bikes and cars also don't really get to speeds that allow the grip required to use slick tyres (which is why they are illegal on the road). Normally, compounds are available with intermediate and full levels.
The decision of when to pit between wet and dry conditions is vital. A great example of this being Jenson Button at the 2011 Canadian Grand Prix. After a catalogue of incidents at the start of the race, Jenson found himself racing through the filed from last place. Having switched back to slicks early, on the last lap he pressured Sebastian Vettel off the road to win a very exciting race!
Tickets for the 2020 Canadian Grand Prix are already available, and is notorious for changing conditions. Don't miss your chance to secure seats in the most popular grandstands with Motorsport Live.
Motorsport is nothing but adaptive, and tyres for motorcycles require some specialist equipment. Tyre compounds can be varied, with some rides preferring softer tyres on the front of the bikes, whilst having harder tyres on the back to deal with the wear from delivering the power to the track. Additionally, there are no scheduled pitstops in MotoGP unless it rains, so riders will switch bikes rather then change the wheels on the vehicle.
As the balance of the bike is paramount to success, tyres have more compound on the sides of the wheel to counteract the leaning of the bikes through turns. The grooved tyres can be used in the wet, however there is some argument to their use at desert races too, as it's not unusual for sand to blow across the track.
In his debut race at the 2017 Qatar MotoGP, Johann Zarco had a super start, finding himself leading his first ever premier class event, however on his sixth lap, he lost grip whilst braking into Turn 2, throwing him off the bike, and the bike unable to continue.
Tyre development is incredibly important to motorsport, it touches on all aspects of the sport from speed and cornering, to rider and driving safety. For this reason, I've always supported the impact that it can have on a race. There have been times when tyre providers have taken things too far with making tyres too hard or too soft, which led to some uneventful races, and the sport suffered. In recent years however, this has been addressed well on all levels of racing. Change is never without controversy though; One of the changes for the 2019 Formula 1 season has been the thinner tread on the tyres which is harder to get to the correct operating temperatures. This has favoured Mercedes as the car has traditionally been harder on the tyres, leaving other teams up in arms.
Additionally, the developments on track often come back to us not just as racing action, but as consumers. Tyres are strong, last longer, offer more grip, keep us safe, and in some extreme instances have even become a fashion label on some high-end cars. Pirelli even offer the print on the side of the tyre walls that can match the colour of the car!
Now, if only we had another tyre war…