The tyres have always played a key role when it comes to performance and those who think that a single tyre eliminates that variable are mistaken.
If there were various tyre manufacturers on track, teams could ask for solutions to suit their needs, but with a single supplier, it is the team that have to adapt their frames, geometries and suspension to the tyres.
This is the reason why attention to detail is obsessive and we see tyres, as in this photo of Aleix Espargarò's Aprilia - equipped with temperature sensors during the tests.
Yes, because even a few degrees can make the difference. To cite just one example, the current Michelins work at around 110° at the front and 120° at the rear. Their pressure, when cold, varies between 1.2 and 1.5 bar, depending on the external temperature, to allow the tyres to reach 2 bar during the race, the optimum pressure.
Above and below this temperature and pressure range, the tyres don't work, or rather, they don't offer optimum performance, cancelling out test days and technical updates. But it's no-one's fault - this is the single tyre guys!