New Pirelli tyre will challenge F1 teams - Williams's Rob Smedley

F1 has revised its tyre rules for 2016, introducing a new compound for circuits where the current super-soft tyre is considered too hard - principally street tracks such as Monaco.

Teams will also be given greater freedom over their tyre choices at each grand prix, with Pirelli nominating a third compound for each event.

Williams has often struggled to get the best from the delicate Pirelli rubber over the past couple of seasons, and Smedley reckons the new ultra-soft will compound the difficulty of overcoming this obstacle.

"I think it's going to be a big challenge for everybody, to be honest," said Smedley, speaking to Autosport at the annual Autosport International exhibition at Birmingham's NEC.

"It's certainly not insignificant, and I would be so bold as to say I think it was sold as a little bit insignificant to reduce the tread depth by 30 per cent and therefore have 30 per cent less wear.

"It's not that simple. You've got very different thermal properties on the layer that sits underneath the compound, and that gives you different properties of the compound itself after a certain extent."

He believes Williams has taken the change seriously enough to find adequate solutions.

"I think we've done the right things," Smedley said.

"We've sat down and we're considering extensively what difference that's going to make.

"We're considering it at a much deeper level technically than just knocking 30 per cent off our wear models."