Dont Rely on side wall stamped sizes !!!
Do your research carefully, check manufactures websites
or go to Tire Rack to see what each tire "Actually" measures when mounted on recommended size wheels
Some 305's are 12.2" and will fit a 4G 1500 4x4 20" x 9" wheel with +19.05 offset (no spacers required, no rubbing)
Some 305's are 12.6" wide....Even a Trail Grappler in 295/65R20 size is wider than many 305's ...at 12.60" = RUB!
My 305/50R20 Terra Grappler's on stock 20"x9" Chrome Clads
work just fine on my 10' RCSB 4x4 Sport ...even after dropping it 2/3
I've been trying to get the message across for 3 years now
after Ground Force 2/3 drop kit