F1 | Miami: one-stop race, but watch out for thermal degradation

The Miami event was characterized by the great heat and a particularly slippery asphalt which faced all the drivers with a complex challenge, that of tire management. In recent years there has been more insistence on how essential it is to bring the tires into the right operating window, trying to get as close as possible to peak grip but without overheating.

This is a fundamental issue, as seen in qualifying both on Friday and Saturday, so much so that several drivers struggled to improve in the second attempt when they tried to force the pace in search of the last hundredths. With the asphalt at almost 50°C, it was easy to overheat the softer compound, as Verstappen understood in the only free practice session: the Dutchman was then a master in managing the soft in qualifying, especially on Sunday, finding a good balance in the use of the tires between the first, full of high-speed corners, and the second sector, the more driven one.

Pirelli engineer Simone Berra confirmed that the difference between the soft and medium compound in terms of performance was more limited than expected by the Italian company itself, thanks to the characteristics of the Miami asphalt, which became rougher with the years pass. This meant that, for example, on Friday the fastest sprint qualifying time arrived in SQ2 with the average, a more robust compound, while then on Saturday the teams took advantage of the experience of the previous day to optimize exploitation of the soft.

The difference between soft and medium is smaller than expected

“We expected a difference in performance between the soft and the medium of about six or seven tenths, but we only saw a couple of tenths of difference. The problem is that soft is very demanding. So when you overheat and exceed your target temperature, you start to slip a lot. And then you start generating even more overheating and you slide even more. These are the factors that create problems especially in low speed areas and when changing direction”, explained Simone Berra.

A very delicate balance, difficult to fully understand, so much so that all the drivers in some way had to deal with the phenomenon of overheating, having to study a tactic to keep the tires alive until the end of the lap. The issue of overheating had a major impact on qualifying, but the rather small difference in performance between soft and medium could also have implications on the race.

On Saturday, despite taking advantage of the little train that formed behind Kevin Magnussen, Yuki Tsunoda was able to make the most of the softer compound, recovering up to eighth place, the last valid to gain a useful point in terms of the standings world. Undoubtedly, the traffic that was created in the short race allowed for particular tactics, but the sprint opened up various considerations from a Grand Prix perspective.

Among the possible strategies for the race, in fact, Pirelli has also included the soft-hard option, with a rather short stint on the softer compound to make the most of the grip in the initial stages of the race, when the group tends to still be compact . A tactic that several drivers could implement: in the top ten the only one with a new set is Norris, but it is difficult to think that McLaren will decide to focus on a tire with which it has struggled throughout the weekend.

Carlos Sainz, Ferrari SF-24

Photo by: Zak Mauger / Motorsport Images

Basically, therefore, it would seem more of an option for drivers outside the points zone, a bit like what was seen in Japan, especially if some clouds were to appear, although in Miami we could also witness the opposite scenario. Those at the back could also opt for a long initial stint on the hard, in order to extend and take advantage of a possible entry of the SC at the right moment.

The challenge is to manage thermal degradation

Looking at the sets available, many will probably opt for a one-stop strategy consisting of medium and hard in succession. As long as tire overheating is kept under control in the race, pure tire degradation in Miami is quite limited, opening up the possibility of stretching. Clearly medium and hard are the coverages with which it is easier to manage this phenomenon, which is why the medium-hard choice represents a very flexible option.

“In our opinion it will be a media-hard strategy. Maybe there will be some drivers who will try the harder tire at the start of the race to go long and take advantage of a Safety Car given that it is a city track. But soft-hard can also be an option, using the softer compound to try to gain some positions at the start. Among other things, it could be an option to avoid traffic, you stop first and then on the hard you are in clean air and can push your pace”, explained Berra, even if clearly anticipating the first stop too much will force you to travel a long way very long second stint.

In terms of pure degradation, there don’t appear to be any major problems. In fact, the degradation found seems to be minimal, so much so that according to Pirelli, in terms of tire life, over seventy laps could be completed with the hard tire, beyond the overall length of the race, while with the medium one it could even reach fifty total passes. “Even in terms of wear it is not a problem, the durability is quite high. On average we have estimated that around 50 laps can be done. With the hard one you can also do 70-75 laps, therefore a considerable amount. Honestly, you could do the entire race on hard. If you wanted, you could also do it with the average, but not in terms of performance, but of wear”.

Yuki Tsunoda, RB F1 Team VCARB 01

Photo by: Andy Hone / Motorsport Images

The last sentence is perhaps the most important because, while it is true that pure degradation is not particularly high on this track, on the other hand the real problem will be the management of thermal degradation. In Miami, in fact, tire life is not a concern for the teams, but it is clear that on an asphalt that reaches almost 50°C, temperature management has a great influence on performance. For this reason, in scenarios like that of the US race, we talk about thermal degradation.

This degradation will mainly affect the rear axle, the one put under the most stress during the lap. The interesting aspect is that, despite there being two very long straights, the rear axle tends to lose less temperature than the front. Furthermore, dividing the sprints there is a very tortuous part where the traction phase mainly counts, shifting the focus once again to extracting the maximum from the rear axle. Considering that even at an environmental level it reaches 30°C, it is not surprising that the surface temperature remains very high.

The drivers and teams will have to be able to wisely manage the rear and the relative thermal degradation, because when the tire overheats, not only does it become difficult to recover the tires which start to slip, but there is also a significant drop in the of performances.