Hamilton confused by Ferrari's wet tyre tactics

Lewis Hamilton topped both free practice sessions on Friday, with the Mercedes driver completing very few laps in Austin.

Hamilton kept his lapping to a minimum, unlike Mercedes' rivals Ferrari, who need to win this weekend to keep their ever-fading title dream still alive.

"It wasn't about the risk," Hamilton told RaceFans. "It was more just we have a certain amount of sets of tyres and if it rains tomorrow in qualifying and (FP3) we want to use those other sets that we have and save them for qualifying.

"When the tyre's brand new it has sharp edges on the tyres. For example, a tyre that's used, once you scrub the tyre in you start to tear those edges up and what that means is it doesn't get rid of the water quickly enough."

Hamilton seemed very confused about the way Ferrari were handling their tyres in Friday's two free practice sessions.

"But I see the Ferraris just pounding around, destroying their tyres," Lewis said. "They've gone in (second practice) again pounding around and they've got no tyres left. So if it is wet tomorrow, they'll have one set less than us.

"It might not hinder them too much but we think more long-term. I could pound around and do 10, 15, 20 laps and it wouldn't make a difference, I'd still be able to do the time that I did.

"You can find some things on your laps but better to do it in qualifying, or (final practice) at least."