As detailed yesterday, a new system to retain the smaller, lighter wheel nuts in the rim has been proving problematic for teams, with those that have tested in recent days trialling several solutions.
However that isn't the only issue with the new Gen3 wheel and hub package, with the mounting the rims onto the drive pegs during tyre changes proving difficult.
It appears the issue is most prominent when mounting a cold wheel onto a hot spindle – which will be the case during in-race pitstops.
According to Erebus CEO Barry Ryan, who has spent a collective three days running his new Gen3 cars this week, the outcome to the retaining clip issue could eventually be a whole new wheel nut design.
As for the mounting issue, Ryan says the category can potentially deal with it for the opening round of the season in Newcastle, where stop times will be dictated by refuelling.
However a permanent fix is required for the first sprint round of the season at Albert Park in late March/early April
"[They are] totally seperate [issues]," he told Motorsport.com.
"[The retaining clip] still needs a bit of work. We've all tried multiple things now, but I honestly think the solution will be a whole new wheel nut.
"The cold wheel going onto a hot spindle, the jury is still out on what the fix is. There are a couple of different theories and not many teams are aligning on those theories.
"Once we've done all this running a few of the influential heads and engineering brains will get together and we'll work it out.
"We've still got the all-in test in Sydney and a few people testing after that as well, so we'll work it all out before Newcastle. And worst case, there are things we can put in place to make it work to get through Newcastle.
"It's not like there are wheel critical pitstops there, they are more fuel critical. I think in Newcastle we'll get by no matter what, but we need a proper solution for when we're doing fast pitstops at the [Australian Grand Prix].
There is a total of 11 Gen3 cars in action at Winton today with two from Erebus, two from Walkinshaw Andretti United, two from Tickford Racing, four from Brad Jones Racing, and one from Grove Racing.
