Formula One teams are to try out slick tyres again in April, as official tyre supplier Bridgestone continues to potential changes for the 2009 season.
Slicks were used for the first time in several years during testing at Jerez last December, and drivers were impressed with what they experienced during that early running.
Now Bridgestone is to continue testing work of the slicks and will deliver more experimental sets for teams at the next major test in Barcelona on April 14-17.
Tetsuro Kobayashi, Bridgestone's technical manager, said: "We are looking to a possible bigger change (to tyres) for next season, and that is why we will be evaluating our latest slick development tyre when we next test in April."
Bridgestone has also confirmed that its range of tyres this year will be mostly unchanged compared to last season's specifications. The only modification will be to the super soft compound, which had caused some issues for teams when it was used in 2007.
"The changes are very minor evolutions to the tyre construction and relate to safety," said Kobayashi. "In terms of car set-up and driver feel, there is no difference from last year's tyres so all the data accumulated last season is of use.
"We have modified the super soft compound, but this will not be seen in use until later in the year. The other compounds, the hard, medium and soft, are the same as last year.
"We will soon announce our tyre compound allocations for each race for the first half of the season, and teams have already been informed of these decisions."