Pirelli has unveiled a concept for new 18-inch tyres to be used in the future for Formula 1.

The Italian manufacturer used the second day of this week's Silverstone test to showcase an experimental larger wheel instead of the usual 13-inch wheels.

Pirelli's motorsport director Paul Hembery told Sky Sports News: "I participate at F1 Commission meetings and we've been discussing new regulations and rules for the future and discussions have gone to rim sizes, 18, 19, 20,

"We just thought it would be far better if we actually did some and showed people what it looked like and then we'd get a reaction."

Hemberly added that an increased rim size is unlikely to be implemented for several years.