i rang up NRMA to see what wheel i could put on my 73 bus. they said with 3rd party property they would only insure it if wheel/rims were less than 6 inches. not sure if that is for comprehensive but it would be a shame to have a claim rejected esp if you crashed into a Rolls Royce or something. you may want to check your insurance if you have wide wheels. i'm pretty sure stock rims are 5 1/2 inches. they said that it didn't really matter about tyre size.