One of the earliest Event Notes issued by the Race Director for a race weekend contains Pirelli’s prescriptions for the tyres selected for that weekend. These prescriptions (mandatory rules) cover, amongst many others, the minimum tyre pressures.

Why is there a minimum tyre pressure even mandated? Because the lower a racing tyre pressure is, the larger the contact area of the tyre on the circuit surface. The larger the surface area contact the greater the traction. To avoid teams having such low pressure that the tyre may fall off the wheel rims, a minimum tyre pressure is mandated. In essence it is a safety issue.

For the Las Vegas race weekend-

A Minimum Tyre Pressures

On closer examination of these minimum tyre pressures and compared to those for other race weekends this year, these are the highest minimum pressures so far. Sounds strange to have highest minimum. This is in the context that a 28psi minimum is higher than a 26.5psi minimum.

What is strange is that the Pirelli preview chart for this event shows the asphalt grip of this circuit as being very low (1/5). One would assume that a larger tyre contact area would be desirable to counteract this. There is obviously some other consideration which prompted this high minimum pressure.

The Pirelli preview-

The range of the minimum tyre pressure so far, this F1 season-

As can be seen from the above the highest minimum for Las Vegas applies to the slick and intermediate tyres and not the full wet.