Pirelli expects Japanese GP to be first two-stop F1 race since May

Although a washout in FP2 meant little information could be gathered about degradation at Suzuka, Pirelli's simulations suggest a one-stop strategy will be too much of stretch for the super-soft tyres on which the top 10 drivers are likely to start the race.

It would be the first time since May's Spanish Grand Prix that the majority of teams opted to make a second stop in ordinary circumstances, although a number of drivers switched onto a similar strategy in Belgium in August as a result of a safety car period.

With the threat of rain also lurking for FP3, teams will have had less time than usual to understand what levels of wear they are likely to encounter in Sunday's race.

"Today we've seen in FP1 some teams running with a high fuel load," said Pirelli's head of car racing Mario Isola.

"Because they wanted to collect some information, especially on the super-softs. No long runs [were completed], because they had no time to do that.

"We have no numbers on degradation, we are waiting for FP3. If it is dry, maybe we can collect some numbers to have a better idea of degradation.

"If I look at the simulations, we believe that it is a two-stop race, because one-stop is marginal.

"A one-stop [strategy] means a very long stint, they should target a stint on super-softs that is at least 18-20 laps, and the rest on softs, and it is marginal for one stop.

"We think we have some degradation on the super-softs, and it is probably not an advantage to keep the super-softs for a long stint like that.

"If the quali is dry and they start on used super-softs, it means you have a tyre that at the end of the stint has 22 laps. That is a bit too much here in Suzuka.

"Twenty laps for us is probably the limit at Suzuka, and 30-35 is the limitation for the soft.

"Here the pitstop loss without the change is around 18s, so they don't lose a lot of time in the pit stop. That's why a two-stop is possible."

The difference in laptime between the two compounds is expected to be around 0.7 seconds at Suzuka.

Pirelli's soft front tyres took some time to come up to temperature in FP1, which could make it harder for a driver to perform an undercut if it remains cool on Sunday.

"This morning it was difficult to warm up the soft compound, conditions were quite cold, while with the supersoft we had no issues," added Isola.

"If we have on Sunday a dry conditions with a temperature like we had now, this could be an issue on the out lap."