Pirelli found in pre-season testing that the new asphalt at Spain’s Circuit de Barcelona-Catalunya produced more grip and less tyre wear, which means more rubber stayed on the tyre which in turn can lead to surface overheating.
As Great Britain’s Silverstone and France’s Paul Ricard circuits also feature new asphalt for this season, like Barcelona, Pirelli opted to reduce the tread depth, and therefore the amount of rubber on the tyre, for those three races.
“This was a recommendation that we ourselves brought to the FIA – as we have done in the past at some races – because it is less disruptive than nominating harder compounds, which was the alternative,” said Pirelli’s Head of Car Racing, Mario Isola.
“Apart from making a set of tyres weigh around one kilogram less, there is no appreciable difference in performance; so in effect this is an ‘invisible’ change.
“It only applies to the three races in Spain, France and Britain: there is no alteration to the tyre specification planned for any other events.
"We tested the solution last year, and in terms of performance or other consequences, they are almost transparent.
"Obviously the reason we stayed on the standard tyre for this year was in normal circumstances you wear the tyre, and if you don't have enough thickness, you wear the tyre too quickly."
This is not the first time Pirelli have made such a request - the tyre supplier reduced the tread depth in 2011 and 2012 for the Belgian and Italian Grands Prix.