A 295/30R18, but you will need to roll/cut the fender lip a little over 1/4". The 285/30R18 is a better fitment, the 295 is a little wide for a 10" wheel. It will work, but the contact patch rolls up at the edges so it doesn't help. The largest you could run without rolling/cutting the fender is a 265/35R18.
Later, Steve