Grooved rubber was a hot topic in the Supercars paddock on Sunday after the second of two 250-kilometer races was canceled due to rain.
The field went a few laps behind the safety car before being called back to the pit lane, where it sat for 35 minutes before a decision was made to abandon the race.
Opinions among drivers were divided as to whether or not this was the right call, while TV interviews during the initial hiatus provided a number of indications that the Dunlop Control Wet Tire was not “fully” wet to deal with standing water To finish.
The long-standing wet, relatively unchanged over two decades as a control supplier, is more of an all-rounder that is suitable for the relatively mild Australian weather and is therefore more tolerant of drying conditions.
However, that makes it prone to rare instances of monsoon rains, as seen over the weekend at SMP.
According to Kevin Fitzsimons, director of the Dunlop Supercars program, getting a wet out is entirely possible, but it would drive costs up and waste as it is so rarely required.
“[The current tyre is] classified as a rain tire, but it is really an aggressive intermediate tire, “Fitzsimons told Autosport.
“It has a lot more grooves than a standard intermediate when you have a full wet, an inter, and then a slick.
“But its composition is harder than a full-blown wet. And a full wet would have a much more aggressive pattern for draining water.
“In addition, it would bite 80 percent faster on a drying track than this current rain tire.
“The tire is fine when the conditions are right, but when it rains heavier, like we had at the weekend, it’s not ideal.
Chaz Mostert, Walkinshaw Andretti United Holden
Photo by: Edge Photographics
“We could make a more effective rain tire, but it won’t last as long as the current one. So the teams have to have slicks, intermediates and rain tires. That means they need more wheels to fit them.”
“And how long can you keep them? Four months? Six months? Twelve months?
“It’s just a matter of money. We don’t have that many rain races, it’s not like we’re in Europe and we keep putting rain tires on.
“For 20 years [the current wet tyre has] been good. These comments come back every now and then, especially when the guys weren’t having a good weekend.
“It’s easy to point with a finger that the rain tire is not ideal.
“We know that it is not ideal in all conditions – but it does its job perfectly to do it perfectly. And that means not throwing blocks at the spectators after eight laps on the drying track.”
Fitzsimons added that teams often fail to help the tire set up, especially if they think the track could dry out during the race.
“It also depends on the vehicle set-up, where there is a compromise, when [teams] hope it might dry out, “he said.” So leave the dry setup with the camber.
“This means that two thirds of the tire have no contact with the road surface and the water does not pump out. You’re basically riding on a 150mm wide tire as opposed to a 300mm wide tire.
“We’re getting the tires back and the outer blocks haven’t even touched the track. They still have all the ventilation pits. It’s really, really obvious.”
As for the Sunday wash-out, Fitzsimons admitted that there was probably a bit too much standing water for safe racing, even with the cars on a completely wet setup.
“There was a lot of stagnant water here,” he said. “[The tyre] can only pump what he can pump. When you’re traveling very, very fast and the water can’t be pushed out, aquaplaning comes along.
“When the red flag passed I went down to the pit exit and looked through Turn 1 and there was a considerable amount of stagnant water.
“The surface on SMP is particularly worn, so at the shootout we saw people off the top trying to find sharp rocks to dig into the tire. That makes it difficult.”
