I discovered rather late that the vinyl inserts for road wheels (re: academy merkavas and M60s) should not be painted with enamels. My road wheels were melted by the vinyl when it reacted with the fla black enamel paint that I used. Acrylics I was told is what I should have used.
When I built my Merk II, I installed the vinyl portion after painting the wheels. I used an enamel wash and drybrush on the vinyl with no ill effects at all.
GipWinecoff