I'm thinking about getting a set of mud tires; the trails I run are mainly packed to loose dirt and of course mud when it's been raining.  I want the jeep to get through mud better.  Currently I go out with my dd 32x11.50x15 BFG AT's.  I've heard several times that the smaller contact patches of more narrow tires can help in some circumstances (more pounds of down-force per square inch of contact is the standard reason given).

narrow can work very well in mud.

back in the day the people that could get the farthest in mud bog competition used narrow tires, they only went to wide tires when the power got high enough to basicly skip across the mud without sinking at all and it bacame a timed competition, not a distance competition. If you ever watch those swamp buggy races, they all use extremely narrow tires. the concept with narrow tires is you sink till you hit sollid terrain. in bottomless mud pits or sand dunes, you want wide. for the big time rock crawling wide is probably better too. for everyday off roading narrow is probably the better choice. for fuel efficiency narrow is also better

That sounds like solid advice - thanks. 

The military had pretty narrows on their's for some reason didn't they...

Mud-slicks vs. mud-holes:  some trails (if hit right after a rain) can just be slick all the way around.  My objective is to perform better in this scenario as opposed to excelling at getting through real deep mudholes or mud-bogging.  Also, the trails I typically run have some rocks to crawl but not that much.  So which way would you all lean on width under these assumptions?

I'd go with your narrow swamps or some 33x9.50 BFG muds (they will fit your rig).

the wider tire might give better road manners.

I'd also dump the wheel spacers, your wheel bearings will thank you for it, and you shouldn't need them.

If your drive on the street as well I'd go with a 32 10.5" just my 2 cents

Groo:  I didn't realize wheel spacers would damage bearings anymore than wheels with more backspacing.  Why do they?

96 zj:  The tires I'm considering getting would be mounted on separate wheels and a second set in addition to my 32x11.50 BFG AT's I use for daily driving.

they wont (I still dont trust them, it another weak link were it wasn't ment to take it), but too little back spacing damages bearings too. the unit bearings on modern jeeps are very narrow. I've seen them fail with tires less than 30" but sticking out too far in under 30,000 miles. and like I said, you should be able to get by without them, so why wreck your bearings when you don't have to  

overhung load.  no it's not a sex thing. 

For laughs, overhung load can be demonstrated by holding a pipe or a rod of some sort horizontally.  if you hold it in the center, it's the easiest to hold.  if you hold it to the right or left of center, it gets heavier on the long end. That extra weight is what is called overhung load.

Say you draw a center line around your tire, on the center of the tread.  If that line was inline with the center of the wheel bearing that would give you max efficiency for the bearing.  Every inch that tire center line moves inside or outside of the bearing center line, is more overhung loading the bearing takes.  so if you're tires are sticking way outside your jeep, your bearings, and other axle parts, are in hell.. especially if you wheel it.

Seems to me that rule applies the same whather there is a spacer or back spacing..   course, if there's both then ya better have beefy axles.

Thanks for the heads-up on this Groo.

Thanks for the explanation - makes sense.