I ran 37x12.5 for several years on my Toyota, they worked great for me and I never had any problems with them. They do have a weak (radial) sidewall. I bought my tires used and the spare had been punctured with less then 1 mile of trail on them.
Good street manners and worked pretty good offroad as well. At least the price has come down on them a little. :tonka: and you can get them with a 20" wheel