F1 teams face unusual strategy headache in Spanish Grand Prix

Pirelli's selection of tyres for this weekend has proved to be a step too hard, with the hard compound of no use, and the medium around two-seconds per lap slower than the soft.

With the rules requiring drivers to run two different compounds in the race, F1 teams will have to work out ways to use the medium tyres for the shortest time possible.

Pirelli's F1 racing manager Mario Isola told Autosport: "The soft is performing very well, and medium is sliding a bit.

"The quicker strategy is on three-stops, with three sets of softs and the medium used for very few laps.

"The two-stop strategy with soft/soft/medium is possible. It is a few seconds slower [in theory] but you are not in traffic.

"Considering this is a circuit where overtaking is not the easiest thing to do, probably a lot of teams will have to run 25 laps on the soft, that means 50 laps total, or as long as possible on the soft, to have a [short] last stint on the medium tyre."

When teams choose to run the medium stint could vary, and Williams technical chief Paddy Lowe reckoned that, with such a big difference between tyres, there could be enough of a lap time delta to help overtaking.

"It is an unusually big gap, so it has already affected how we analyse what to do," he explained.

"It will create interest in the race, and it is the differentials that give overtaking ability, the possibility of different strategies and unexpected outcomes.

"So it is probably good for the spectacle."

One other potential area of interest is the way that the new 2017 cars have changed the nature of the final corner, which could also help overtaking.

In the past, overtaking at the Circuit de Catalunya was very difficult because it was too hard to follow another car closely through the fast final corner.

But with cars now having more downforce, and the last turn being easily flat, it should be easier for cars to stay close to each other to then take the benefit of the extended DRS zone which has been increased by 100 metres.

Lowe added: "It is a notoriously difficult track here to overtake, as we have seen here in the past, so it will at least give ourselves the best chance."