In each of the three sessions, one of the WAU Mustangs had an issue with respect to crew members fitting a new wheel.
The problem is a known one, which arose during pre-season shakedowns/testing, and is caused by a discrepancy in the temperature of the cold incoming rim and the already hot spindle.
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However, a fix has been arrived at and for Mostert, who was third-fastest in practice in his #25 Mobil 1 Optus Mustang, the matter is not a significant concern going forward.
“Not so much,” he said.
“I think a lot of teams do this stuff with rims and tolerances and all that kind of stuff, but we have practice rims and we have race rims and it's just the way our car is for this weekend.
“So I'm sure, after a couple of rounds, and we get some more time, we'll get all the sets of rims up to standard but at the moment I'm not stressed out for the race.”
That solution has in fact been implemented, including for the rims which WAU will use in qualifying and racing, Team Principal Bruce Stewart confirmed to Speedcafe.com.
“When you've got new parts and components on cars, there are always going to be teething issues, and that's up and down the category,” said Stewart.
“When you have a vehicle that's done a lot of laps and accumulated a lot of heat, and you've got a hot spindle and a cold wheel going in, then you can get a little bit of difficulty getting it on.
“We don't envisage it's going to be an issue tomorrow, but in that respect, you can never say never, so you've just got to make sure our guys do as good a job as they can in the pit stops and press on.”
Qualifying for Race 1 of the season at the Newcastle East Street Circuit starts tomorrow at 11:15 local time/AEDT.