Slowly,
Try a place called Tough Tyres, they are in Ferntree Gully,
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http://www.toughtyres.com.au/
Got mine from there a couple of years back. If not, contact Yoki and see when next lot due in, I was told they run a batch every now and then.
or
try Ebay, there has been a couple of new sets sold over the past few months
Let us know how you go
Dale.