Let me try:
Cars originally equipped with metric 365 wheels may fit fourteen (14) inch wheels. Cars originally equipped with metric 390 wheels may fit fifteen (15) inch wheels. Cars originally equipped with wheels smaller than (15) inches may fit a larger than GCR-specified wheel up to fifteen (15) inches. All other cars shall retain the wheel diameter fitted as original equipment for their make, model, and type. Knockoff/quickchange type wheels are prohibited. Wheels must be made of metal.