Frankly, I don't give a tinker's damm what anyone puts on their motorcycle.
Here's the truth:
Car wheels (rims) and motorcycle wheels have different beads as do the tires that are designed to be mounted on their respective, appropriate rims. In this country, you run the risk of invalidating your insurance by cross-mounting tires on rims that they are not designed for. Federal regs are the guide - D.O.T. - feel free to look it up yourselves as I did years ago.
Insurance cases have been made, adverse to car tire users on motorcycles. Why don't you hear about it? Simple, when the settlements are made, the insurance companies invariably require non-disclosure agreements from their formerly insureds, who may have incurred or caused or experienced a personal liability. Insurance cos. will do anything they can to legally avoid paying out claims.
Run a motorcycle tire... as I said, I care not. Just don't go whining to anyone if you have, cause or are involved in an accident, because if your insurance company decides to handle your case as they will if they ordinarily would have to pay out a claim when personal liability is involved, you will be S.O.L. and possibly much poorere for it.
More than likely, this scenario would play out even worse in Australia where they have some really Gestapo-like policies when it comes to vehicular regs.
BTW, Openroad, I speak from both experience and knowledge. I've previously run car tires on three different large cruisers for a sum total of approx. 30,000 miles. That includes 7,000 miles of the ****tiest handling, highest personal risk and tiring, physical, overcompensating, wrestling match-like miles that I've had out of the nearly 25,000 miles I've put on my Rocket.
My $0.02...