For the Belgian Grand Prix, Pirelli's C2 compound has been selected as the P Zero White hard, C3 as the P Zero Yellow medium, and C4 as the P Zero Red soft. This is a step softer than the nomination at Spa last year.
This choice has been made because most drivers chose the medium and soft tyres last year. In fact, many drivers selected a full allocation of 10 soft tyres in 2019 and only one hard (although this will not be possible this year as all the allocations are standard: two sets of hard, three sets of medium, and eight sets of soft).
The weather in Belgium at this time of year is extremely variable. Although high temperatures have occasionally been seen at Spa in the past, in the Ardennes we're unlikely to have the same sort of weather as Spain (last year's Belgian Grand Prix was run with track temperatures consistently below 30 degrees centigrade) - and rain is always a distinct possibility. It is even possible for it to be raining on one part of the track but dry on another. If it does rain, drainage is a common problem, with little rivers forming across the track that can cause aquaplaning. This is another reason why the tyres in the middle of the range have been selected.
This variation is also because the 7.004-kilometre lap - the longest in Formula 1 - is so extensive and mixed, with epic corners such as Eau Rouge imposing heavy combined forces on the tyres: both vertical and lateral. As a result, Spa is one of the most challenging circuits for tyres seen all year. The asphalt is also quite aggressive in nature.
It is not just the corners that provide a big challenge: at nearly 800 metres long the Kemmel Straight cools the tyres down, affecting grip throughout the following corners.
Despite the imposing demands of Spa, it was largely a one-stop race last year, with the top three all using a soft-medium strategy (with a nomination that was a step harder). Three of the drivers in the top 10 stopped twice, while Renault's Daniel Ricciardo did practically the entire race on the medium after a very early stop.
Mario Isola: "The reputation of Spa speaks for itself: it's an old-school track with plenty of elevation and other variables, which the drivers love because of the many challenges and sensations that it delivers. This year's tyre selection is a step softer than last year's, even though we expect the cars to be considerably faster, as has been the case for most of the season so far.
"Spa is one of the few rounds this year that has not had a date change compared to its traditional slot, so the teams should have plenty of relevant data, even though this is probably the circuit where it's hardest to predict the conditions. So the teams and drivers who are best able to rapidly adapt to changing circumstances tend to be those most rewarded.
"One difference this year is that the Spa 24 Hours hasn't taken place as usual a couple of weeks ago: it will be interesting to see if that has any effect - although any rubber that is previously laid down is often washed away by rain in any case.
"Finally, but most importantly, I am sure that Anthoine Hubert will be at the forefront of everybody's minds this weekend and we would all like to pay tribute to him, a year on from his passing."