Hi What is the tyre size range that will fit on a 18 x 18.5 rim. For instance would a 215 40 18 fit on the rim. I have seen all the online calculators which give different results.
On a 18.5" rim, you will want a tire that is between 18.5*25.4 (470) and 19.5*25.4 (495) millimeters wide. However, I think you are looking at 10.5" rims and those take tires between 10.5*25.4 (265) and 11.5*25.5 (290) millimeters. A 215 width tire wants about 215/25.4 = 8.46" rim width