The softer, Gen3-Spec wet tyres could leave Supercars teams and drivers with a real headache if weather at the Vailo Adelaide 500 remains changeable.

Practice 1 for the Repco Supercars Championship finale was wet throughout, but the extent of the rain was variable during the half-hour hit-out.

While the choice of wets then was relatively straightforward, even if Red Bull Ampol Racing did attempt a slick run for Shane van Gisbergen, tyres could become a far more difficult call in tomorrow’s 78-lap race.

Supercars moved to a softer compound of wet tyre this year which gives drivers the confidence to push sooner, as Nick Percat attested after Practice 1 in Adelaide.

The flipside, as some barely wet races at Albert Park demonstrated, is that it will degrade far quicker when the track is drying out.

Brad Jones Racing’s Andre Heimgartner, who was second-fastest in that session, noted, “None of us have really done any meaningful testing on it.

“We had it at AGP and it was pretty difficult, you can only get halfway through a lap and they sort of deteriorate.

“[It was a] very different style of track and I think we’ve all learned a bit from then, too.

“It was good to get a few laps and they’re definitely gripped up but it’ll be more the longevity that everyone will be working on.”

According to the R&J Batteries Camaro pilot, the crossover point between wet and slick will be less obvious than before.

“I think it’ll be fine if it’s a totally wet stint but here, often, it’s drying or there’s a drying line,” added Heimgartner.

“So you’re going to see a bigger blurred line between how we used to have the old [wet] tyre and you get down to whatever the [lap] time is and you put dry tyres on.

“I think there’ll be a bigger crossover to some extent because the wets just won’t hang on, so there’ll be a real fuzzy phase in the race where it’ll be pretty dicey on either tyre that you’re on.”

Grove Racing rookie Matt Payne, who wound up third in Practice 1, had a similar take from his Penrite Mustang.

“The track was the sort of wet but it was drying as well, so there wasn’t enough rain to keep it at the same sort of condition, so it was going to just chew up our tyres,” he recounted.

“Like Andre said, it’s going to be interesting with those tyres. I think it’s a lot different to previous years when the wet tyre sort of used to behave.

“Now it’s going to be a lot of track-driven with different pressures and things like that.

“It’s interesting; it changes the game a little bit.”

The weather in Adelaide is presently cloudy but the chance of rain has dropped only slightly to 90 percent, and is 90 percent for tomorrow also, per latest forecasts.

Notably, showers tomorrow are most likely in the afternoon, when the penultimate race of the season will be held.

That will please Triple Eight Race Engineering, which is hoping for the weather to create an extra variable as it seeks to overhaul Erebus Motorsport and Brodie Kostecki in both the teams’ and drivers’ championships.

Practice 2 starts this afternoon at 12:35 local time/13:05 AEDT.