Where do I begin if I want to understand tyre tactics better? And what does the type of tyre mean for the performance of the car?
In: 8
Newer tires mean better grip on the road surface, better handling, and better acceleration. Formula 1 teams will generally end up with two tire compounds to choose from for a race. The softer one will provide better grip to the track surface, but will often degrade after just a few laps. The harder compound will not provide the same level of grip, but will last longer.
“Tire deg” (degradation) is a very important aspect of F1, which is how quickly a design of the car will result in its tires “going off”, that is losing their grip and making the car slow. Some car designs are easier on tires than others. Pit stops take lots of time. If a car can keep it’s tires in the sweet spot longer than a competitor, you have a huge advantage.
You probably want to get into the formula 1 sub for specific questions, but I’ll give a brief overview for the people who wander here.
This year, there are 5 tire compounds total for the dry tires. They are designed so that they do not last the full race. And per the rules of the league, each driver must use two different compounds in the race (with exceptions for wet races).
The 5 tire compounds range in softness. The softest rubber compound (C5) is the absolute fastest, but also the least durable; it’ll only last a dozen laps before it’s performance drops off significantly. The hardest compound C1 is the slowest of the bunch due to its lack of grip, but it’ll last most of the race. To add to the confusion, the race coordinators chose only three compounds to take to each race (so that there aren’t 5 sets for viewers and teams to keep track of and stock)
So when it comes to watching a race, the pit stops cost time, so it needs to be worth it to change. Lots of different strategies are viable, but only a few are optimal.
The main issue is temperature. Rubber gets softer and stickier when it gets warmer, improving grip which is valuable for the driver in almost all situations. When it can increase throttle to full power (like coming out a corner), the driver can’t just floor the pedal as tires would just spin, causing the car to fly off the track. In the corners the speed has to be limited in order to not skid to either side. Before the corner, the driver wants to brake as late as possible (to save time) but can’t wait too long as braking too hard will lock up the wheels, causing flat spots. Basically the driver is constantly pushing the tyres to the maximum grip limit before it’s skidding, the more grip the faster he can go.
So you would think hotter tyres = better. But when they get too hot, they can develop melting spots that could even lead to a blown tyre and the wear increase a lot. Meaning the driver is actively maintaining the temperature in a narrow ‘Goldilocks’ range that isn’t too cold but also not too hot. This is also why you sometimes see periods of alternating higher and lower performance by a driver, as when he can profit from driving a bit faster he can sacrifice the tyre temperature in return of for example overtaking or undercutting the competitors. After a fast period you see the lap times increase slightly as he needs to limit speed to cool the tyres again. Another factor is driving behind other drivers, which will deliver hotter air towards the car which cools the tyres down less, hurting performance. This is often why cars can’t easily overtake on narrower tracks unless helped by DRS and such.
Ultimately when the tyre wears down too far, it can’t be cooled as much anymore, basically as it became thinner and less mass gets heated each time, heating it up more. Queue ‘My tyres are dead’ kind of radio messages, the tyres need to be swapped or speed has to be reduced even more. Then comes the type of tyre, that varies with the inherent softness of the material. Softer means more grip at lower temperature, but wears out quicker too. Harder can sometimes, dependent on the actual compound, last indefinitely if not pushed much. The tactics by the team thus boils down to supplying the tires that balance performance vs durability requirements, in practice you often see a soft tyre to start, then a harder tyre to finish.
For a race, there are 5 different types of tires they can use. The wet tire is for standing water when it is raining, and the intermediate (inters) are for damp or less water, between rain and dry.
Then there are three slick tires for dry conditions, hard, medium, and soft. These three tires are selected from 5 compounds, C1 to C5, but all teams have access to the same three compounds for a race. So C3 might be the hard tire for one race, but it might be the soft tire for a different race. Which compounds are used depends on the temperature and track conditions.
The hard tire has the least grip, because it is harder, but will also last the longest before it experiences significant loss in grip. This means the car can do more laps before having to come in for new tires.
The slow tire has the most grip, because it is softer and can form to the texture of the track better, but will wear down faster. Think about rubbing an eraser against paper versus rubbing a hard piece of plastic against the paper. The soft eraser will wear down faster, but will pull against the paper better.
The medium tire is a balance between the hard and soft.
A pit stop can cost the car more than 20 seconds between having to go slower in the pit lane and stopping for the actual pit stop. So when you stop to change tires, others will pass you. Then when you come out of the pit lane you have to make that ground back up. So there is a trade-off, you might go 1 second per lap slower on the hard tire, but it lasts longer so you don’t need to stop as often. Other cars might be changing tires at the same time, so you don’t lose or gain time against them. If there is a safety car, everyone is going slower and you lose less time doing a pit stop (maybe 16 seconds), so you can hope for a convenient safety car if you need to make a risky move.
Then you also have to consider when others will pit. If they pit before you, you will get open track that can be easier to go faster. If they go after you, you will be slowed down by traffic. But the more you drive on tires the slower they get, so if you come out on new tires of the same type as someone else, you will be faster. So you can pit before them, catch up a bit, and when they pit they will come out behind you and then have to try to pass you.
Tire life also depends on how aggressive you are with them. You can use up a set of soft tires in one lap if you go too hard in qualifying. So you can extend or shorten how long your tires last just by how you drive. Towards the end of the race you will see some drivers going slower than they could because they need to make their tires last until the end. The cost of going slower to save their tires is less than if they had to do a pit stop. During the race, you can push harder when fighting for position, but you will have to pit sooner for new tires.
Cars also need to use at least two different types of tires in a race (if no wet or inters are used). A team might try to do one pit stop, running a set of hards and a set of mediums, or do two pit stops using two sets of softs and a set of mediums. Or two mediums and one hard, or two mediums and one soft. It all depends on track conditions, aggressiveness, and strategies.
Temperature also impacts the tires. When tires are new they are colder and will take a lap to get up to temperature. While cold they will be harder and therefore slower, so when a car comes out of the pits you might notice them getting overtaken since they can’t go as fast. The weather also comes into play here. If it is hotter than expected you might need to use a harder tire because the soft will be too soft and wear down too fast. Or if it is cooler you might move to a softer tire.
All this is why sometimes cars will stay out even when they have no chance of being competitive, sort of like Lando in Bahrain last week with the pneumatic issues. By staying in the race the team got a lot more info on the tires than if they just stopped racing. They knew he couldn’t come anywhere but last, but it is better than a DNF, and they get to test the car and the tires. This will help them in future races because they have a better understanding of their car and how the different tires behave. They will watch other cars too, but will get better data from their own. It also gives the driver more seat time to learn the car and various driving modes.
I’ve probably said at least one thing wrong or unclear, so if anyone else wants to add, please do!
In its simplest form: the softer the tyre, the faster the lap time, but the faster it wears out and loses those benefits.
Harder tyres last longer, but are slower.
So it is a balance between fast lap times offset by more pit stops or a slower tyre and less pit stops.
Tortoise and Hare analogy.
[Chainbear](https://youtu.be/wqf-dJyU_WA) does a variety of great and easy to understand videos on numerous aspects of F1