Pirelli has justified its decision to introduce a 'super hard' compound into its range of 2018 tyres as insurance against next year's car development.
The Italian manufacturer, which has been Formula 1's exclusive supplier since 2011, introduced the superhard and hypersoft tyres at each end of its compound spectrum.
But F1 teams doubt the former will ever been seen in 2018.
"Quite simply, it's our insurance," Pirelli boss Mario Isola told Speed Week.
"Basically, we assume we will never use the super hard tyre. But it's still difficult for us to assess how quickly these new cars will be developed, and whether some corners could become critical."
"The hard tyre is enough on the circuits that put the tyres through a lot, but according to the regulations we may add another compound during the season. It's better to be safe than sorry," Isola added.