JEREZ, Spain - Pirelli says it's too early to assess the performance of its new 2014 Formula 1 tyres, despite four days of testing in Jerez in January 2014. Mercedes F1 driver Lewis Hamilton said after the Jerez test: "The 2014 tyres are a little bit better. They're more durable, so you can do maybe 30 laps and have a lot less wear on them but they still overheat, like any other tyre."Pirelli, however, is not endorsing Hamilton's comments, on the basis that the lack of running at Jerez meant "very little tyre work was carried out".MORE INFORMATION Indeed, Paul Hembery was scheduled to conduct media interviews on the last day of the test, but it was called off on the basis that not enough about the tyres was learned at Jerez, according to Speed Week.Motor sport chief Hembery said: "The emphasis was not on tyres during this test. The upcoming tests in Bahrain should allow the teams to focus on tyres a little more, having had two weeks to develop their cars and remedy any issues that have been identified at Jerez."