US GP: Austin grip levels set to leave pit strategy tricky

The new track has left drivers struggling to find grip from their tyres, many taking as many as four laps to get their rubber up to a useable operating temperature.

That characteristic makes it likely that the first few laps of the race, during which drivers have a heavy fuel load, will be particularly demanding.

It also means that there will be little to be gained by trying to overtake a rival by pitting a lap earlier for fresh rubber, fresh rubber likely to prove slower than old tyres until it comes up to temperature.

Mercedes team principal Ross Brawn believes it will be tough to work out the best time to stop for new tyres because of the complications.

"It is a plus and a minus, as you know someone coming in and taking fresh tyres will take one or two laps to do the times," he said.

"Normally someone would want to stop before you, get fresh tyres and go out, then do a fast lap before you come in pits.

"But here there will be a lag before you can set times with the tyres. That means you don't have to try and anticipate anyone in the pits.

"In fact, there is some disadvantage of being the first one in as you have to do one or two laps quite slowly.

"With the two compounds it also varies, as strangely enough the harder compound is easier to get working. The softer takes longer to get into working range, but it has more grip when it gets there."

The way that the two tyres begin to work differently also means that those drivers starting the race on the harder compound could be up to speed quicker than those on the soft.

Pirelli motorsport director Paul Hembery said: "I think the first part of the race with higher fuel load will help some runners further back, and that will be interesting."

Lotus driver Romain Grosjean thinks it will be tricky for drivers to judge the correct tyre parameters in the race and that this could turn the race more of a spectacle than previously thought.

"The first lap of the race is always quite slow so you don't feel the grip, but when you put the hard tyre on it may need three or four laps," he said.

"It is going to be a case of having the rubber, temperature and tyre pressures correct - it is not just one thing you need to get right. It will be a bit tricky to understand everything."