Welcome aboard - 18" are harder to find than 15" or 16" tires (get cheap steel wheels if you are serious about offroading) but more on coming - Google "18" mud terrain" - many are taller than the 30-31" max we have without a lift. Saw Dunlop and Mickey Thompson 18" mud tires at SEMA that are coming soon. You may want to try some All Terrains as well that will be quieter.