Pirelli will make changes to its tyres from the Canadian Grand Prix in a bid to rein back the excessive degradation that has affected Formula 1 this year.

After admitting that having four-stop raceslike the Spanish Grand Prix was too much, Pirelli is to change the tyre structures so they incorporate some of the characteristics from 2011 and '12.

Further meetings are also taking place at its Milan headquarters this week to evaluate whether or not further compound tweaks will be needed.

Pirelli motorsport director Paul Hembery told AUTOSPORT: "We never intended for there to be four-stop races, so we are going to make construction changes to the tyres.

"We will be taking some of the design of the 2013 tyres, but also some of the elements of the 2011 and 2012 products that served us so well during that period.

"We want to go back to having two or three stop races."

2013 CARS UNDERESTIMATED

Hembery said that Pirelli's move to more aggressive tyres for this season had not taken into account the kind the performance steps that leading teams found over the winter, which had put the tyres under too much stress.

"They have basically been stressing everything far too much, and probably we underestimated the performance," he said.

"We cannot test with the current cars, and all we have access to is a 2010 Renault that laps four or five seconds slower than the current F1 cars do on a Sunday.

"So it was a combination of factors that have come together. We didn't want to make too many dramatic changes, and we do not want to penalise those teams that have taken a design direction to look after the tyres.

"Equally, we had to do something to improve the situation."

As well as making the changes to help limit the number of pit stops needed, Pirelli is making the revisions to prevent a repeat of the type of failures that hit Lewis Hamilton in Bahrain and Paul di Resta in Spain - where a cut in the tyre resulted in the tread coming away rather than there being a puncture.

"The failures were visually spectacular, even though the tyre stayed inflated," said Hembery.

"It was a type of failure not seen in F1 before, and it was something we don't like.

"It also helped stoke up opinions in the media, which influenced what the fans thought."