30.5 was an option and with that option should have had 10x20 traction tread for 2wd and mine has 12x24 traction for 4wd. Most machine that went to wheat country had the tall 23" wide tires and 12x16"tall rib tires. You also may see some with the fatback option which is I belive a 16x16 rim with diamond tread tires. The dish was offset really far in wheel, great for breaking spindles........