The toyo m55 is one of the hardest rubber compounds that you can get in a ten ply. I would run 45 in the back and 50 in the front. The only issue is some people are noise princesses and can hear the tire and don't like them. But i drive the first year of the 24v all i here is the engine. But like i said for the three sets i have run of the past 300,000 miles i loved them. They are like concrete when it come to rocks and drive where you shouldn't be i have never got a flat in the woods.