Pirelli 'ultrasoft' will only be used on street circuits
Formula 1 tyre supplier Pirelli says the new "ultrasoft" compound will only be used on street circuits during the 2016 season.
The Italian manufacturer plans to expand its tyre range for next year in order to have greater flexibility when choosing compounds for the grands prix.
The ultrasoft will join the supersoft, soft, medium and hard compounds.
Pirelli's supersoft tyres have been used in just six races this year: Monaco, Canada, Austria, Singapore, Russia and Abu Dhabi.
Hembery says the ultrasoft may have even more limited use.
"It's only for the street circuits because as we saw in Monaco and in Singapore the wear levels are very low at the moment," said Hembery.
"Cars are sliding less and the change we made is a boost in terms of wear levels.
"Maybe too much, but with the lack of testing we're not being able to make any further changes to the product so we're living with that we have because the cars will be quicker next year.
"Every year they improve, so what was okay last year may be quite dramatically different next year."
He added: "The idea is to get two or three pitstops and the compounds next year will be the same as we have this year, plus one as I mentioned, so is not going to be dramatically different.
"Although we're trying to change the internal part of the tyre to create a cliff after certain number of laps which will force teams into making a change.
"But that's not the same we had in the past in terms of degradation. We need to experiment and see if delivers what we expect."
In order to give teams more flexibility with their tyre choices, Pirelli is planning to select three compounds for each grand prix and then allow teams to choose how many of each they want.
Hembery says the final details of the plan will be announced in December.
"In this scenario each team can decide what will be their best compound," he explained. "So it takes the responsibility away from Pirelli and it makes the responsibility for the teams."
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