I have ran these Bias ply TSL's in a 33x12.5 and a 36x12.5. These tires run true to size, the sidewalls are thick, and the tire itself is heavy. I have ripped through logs and roots and never had a problem. I don't rock crawl at all, but I play in the sand alot.
In the sand the 12.5 ones will get you around just fine, if you air down alot like 5-8lbs. How ever when you start climbing tall dunes and you start loosing wheel speed, these will stop climbing and start digging. When they start digging they won't stop
I use these in my 4 banger TJ, I think a rig with a V-8 would do alot better with them, the 4 banger just doesn't have the power to keep the tires spinning.
I rated these tires a 6 because they handle so poorly in the rain, ice, and snow. In the mud they are a 10, and the sand I would rate them a 4. If your jeep isn't a daily driver and you see rocks and mud I would highly recomend them. If it's a daily driver though I think there are some better options.