Supercars tweaks tyre pressure rules in Sydney

The new-for-2021 Dunlop super soft control tyre is set to make its second appearance ofd the season this weekend at the long-format SMP event.

Each driver will have two sets of the super soft rubber at their disposal, which have to be used in the two 250-kilometre, two-stop races (one set per race).

The tyre allocation will be completed by five sets of the hard compound Dunlop tyre, while the soft compound won't be used at all for the first time in the Sydney swing.

Given the super soft proved more durable than expected when debuted in Darwin earlier this season, Supercars has opted to raise the minimum pressure from 17 psi to 19 psi this weekend.

That change will apply to both the super soft and hard compound tyres.

The change, which had been planned for the super soft round at Winton before it was cancelled, should preserve the intended shape of the tyre and help boost degradation.

That will also be helped by cooler conditions compared to Darwin, particularly for Saturday's night race, which will prevent teams from building pressure in the sun and then bleeding tyres to a lower, more efficient 'true' pressure.

SMP's aggressive surface is also likely to help contribute to higher degradation with the super soft.

"[The higher pressure] will crown the tyre across the centre to make it wear," Dunlop's Supercars boss Kevin Fitzsimons told Motorsport.com.

"That will change the tyre life. I'm not sure it will be dramatic, but we will see a change in the tyre life.

"And we noticed it on the Saturday night race compared to the Sunday races [at the first Sydney round], the fact that the teams weren't able to bleed the tyres back after leaving them in the sun to build the heat up. That compensates for what you're trying to do when you're bleeding the pressure out.

"There's a lot of thinking that will have to be put into [the super soft tyre]. The mix and match, and the day/night thing, it's different scenarios and different results from the conditions.

"We know this track is the most affected by ultra violet light of any in the country, so it's going to be interesting to see what everyone comes up with."

Like the second Sydney weekend, which was mixed compound between the hard and soft, teams will have to nominate their chosen starting compound in writing to Supercars at least half an hour before the race.

There will be more strategic flexibility too, with the return of refuelling and the move to three-stint races.

However weather could also be a critical factor, with rain currently forecast for both Saturday and Sunday.

The Supercars field staged its first wet weather night race at the second SMP event.