After their first day of practice at the Miami International Autodrome, Formula 1 drivers complained of a serious lack of grip off-line.
McLaren driver Daniel Ricciardo believes the problem was caused by small stones pushed up by the cars as the new track surface wore down.
“It seems like just the stones are getting loose and kind of get washed just off the line,” Ricciardo said. “So if you miss a little bit the apex, then you’re sliding off and it’s difficult.”
Formula One’s official tyre supplier, Pirelli confirmed Ricciardo’s reasoning, claiming that this is why two parts of the circuit were repaired before Friday’s racing.
“With this new asphalt they are taking off some small stones from the asphalt,” its head of motor sport Mario Isola explained.
“That is something that happened also yesterday after the Safety Car was running and the hot laps.”
“So they put some patches of new asphalt. But still some stones are coming off because we found the stones on the tyres.”
As the surface continues to wear during today’s sessions, Isola said it’s difficult to say whether the condition will improve. This weekend, F1 will share the track with the W Series and Porsches.
“I’m not sure what is going to happen in the next couple of days,” said Isola on Friday evening in Miami.
“Probably it will stay more or less as it is but there is the risk that if they remove some stones, these stones are obviously flying, and when you run on this line then you lose a bit of grip.
“We saw a lot of mistakes today but it’s normal in a new circuit. They have to set up the car and probably they had some snap oversteer that is difficult to control.”
“It loses the stones from the top but you have other stones, so it’s a matter of the aggregate they have used,” Isola explained as he doesn’t expect the problem to go away as the track becomes more worn.
“It’s not that removing the stones that it’s much smoother. It’s the same aggregate, just losing some stones.”
Isola, on the other hand, claims that the track has good grip. He remarked, “We believe the amount of grip is not far from Silverstone.”
“We obtained that notion from our grip tester, which is a machine that we run on track to evaluate grip.” Obviously, we’ll confirm that with the telemetry data today.”
Isola also mentioned that if drivers spin onto the run-off at particular locations on the circuit, their tyres can be damaged.
“When Carlos Sainz spun he was running over the blue run-off area that is very abrasive,”Isola said.
“It’s similar to Paul Ricard that obviously is made on purpose to slow down a car.”
“But the result was that the puncture on the front-right tyre was because of the sliding on this blue area, and he had a hole like a coin on the tyre. So basically he was sliding and it damages the tyre.”
“If during the race or during practice, a driver is making a mistake and running or spinning on this area then the flat-spot is guaranteed. So basically he has to go back and change the tyres because the vibration can be quite high.”