Pirelli calls for Jerez resurfacing
Hembery claims that this week's first action at Jerez has been compromised by the surface being too rough to allow proper evaluation of tires.
"The track is rather abrasive – and is substantially worse than last year," said Hembery, when asked by AUTOSPORT for his feelings on what had been learned this week.
"We have seen quite a lot of shredding of tires, and there seems to be a lack of bitumen in the track, so we are looking at a very open surface.
"It has meant that what was historically an interesting track from our point of view for doing tire compound work has proven to be probably dominated by that effect, so we have not seen the differences between the compounds that we would have liked.
"We have still seen peak performances of half a second between different levels, and the hard tire has been working quite well considering those conditions to get through their work, but there has been this stripping action across the top of the tires."
When asked if the track was now too rough for useful tire work, he said: "Certainly for tire evaluations, yes. It is a shame because the weather conditions are not too bad.
"You struggle to get anywhere above 20 degrees in Europe in February, so it is slightly disappointing from that point of view.
"But it is quite a big evolution from last year; it is so far away from anything else you are going to see in terms of macro." Yahoo Eurosport UK