Marko wants tyre improvements 'as soon as possible'

Apr.30 (GMM) Dr Helmut Marko has admitted he is not satisfied with the minor tweak made by Pirelli ahead of next weekend's Spanish grand prix.

So far in 2013, world champions Red Bull have been putting pressure on F1's official supplier to significantly change this season's heavily-degrading tyres.

But, after the first four 'flyaway' grands prix, Pirelli has announced that only a minor tweak will be made to the 'hard' compound tyre for Barcelona and beyond.

Red Bull's Marko said on Monday: "We want - as soon as possible - a tyre that does not limit our potential," he is quoted by DPA news agency.

"It should be that you are able to get the most out of your car," he said at the Red Bull Ring circuit in Spielberg, Austria.

Marko argues that the current Pirelli tyres are penalising the very best cars, like Red Bull's RB9.

"If we use our full potential, we cannot even last a full lap of qualifying," he claimed.

"To tell your drivers that they are not allowed to drive some corners properly is not easy," added Marko.

A Red Bull team insider told Germany's Auto Motor und Sport: "If we had a normal tyre, Vettel would be half a second quicker than everyone on each track.

"We know it from our simulations," the source added.