I love the debate on tire width and snow. Nick is correct about skinny/grip.

Slightly off topic the topic is that one downside of wider tires is they rub with standard suspension. If that's of any help. But look cooler in the shopping mall.

Mud, not sure. Is that the same as snow? Physics of off road vehicles needs to book I'm not qualified to write.

 

As far as width goes, wider us better if mud is deeper than axles, skinnier is better if you can reach the bottom with them. Same goes for snow. However, mud tires are quite bad in the snow because the treads clean out too well. For snow you actually want your tires to get packed in for best traction.

 

I'm running the 245/75/16 Goodyear Wrangler Authority tires sold only by Walmart. They look very much like the Duratracs. I love them! They were great in the snow this past winter. Good on trails and mud. A little louder on pavement then some may like but not bad for me.