I modeled this Toyo M/T Open Country as a part of one of my concepts. It's almost accurate model, but I don't claim it to be perfect exact model of the actual tire. The whole model contains two parts : 1-The tire body 2- Sidewall details
The tire is one piece and it's easy to modify the sidewall and side profiles to your preference. I use meshsmooth , u can change the modifer to your preference or change the iterations of the meshsmooth.