We're going to let you in on the secret on how not to get stuck in the mud. The key is not to let any part of your rig-besides the tires-come in contact with the mud. As far as we're concerned, when you are in mud, you never want to dig down into it. You want to skim across the top of it. If your tires dig down, your axles drag through the sticky goo, slowing you down and causing you to dig down more. By the time your transfer case gets in the mud, you're pretty much doomed to a tow strap. Before you know it you've lost all forward progress and dug the tires down deep enough to leave the truck resting on its framerails and you're hopelessly stuck.
How do we know all this? By making lots of mistakes, of course! To research this story we recently took our Ultimate Super Duty (USD) out to Azusa Canyon in the San Gabriel Mountains to see how our 9,000-pound F-250 riding on 46.7-inch Michelins would do in the mud. By no means did we master the mud (or anything else, for that matter), but we did learn a lot about what makes a truck work in the mud...and what doesn't. If you were there you know we broke an axleshaft and a 35-spline hub, smoked our 15,000-pound winch, and had to get dragged to safety. But it was all in the name of research and if you can use what we learned to help you build your own ultimate mud truck, or at least improve what you've got, it was worth it. OK, it was worth it even if our ideas don't help you.
Tires/Wheels/Air PressureChoosing the right mud tires is a matter of matching the size and tread to your vehicle's level of horsepower. The better your power-to-weight ratio, the more aggressive you can get with your tire choice. Tall wide tires that will give you floatation and keep your axles out of the mud are your best bet. Trucks with a lot of power may benefit from a set of Interco (337/334-3814, www.intercotire.com) Super Swampers or Boggers because their fierce paddles and huge voids will move more mud than any DOT tire out there. If your rig lacks power, or you find that Boggers and Swampers dig too much, consider a set of Denman (www.denmantire.com) Ground Hawgs with the less aggressive paddles. You might even try running Boggers in the rear for thrust and Swampers in the front for better steering and to keep the front end floating on top of the mud. No matter what tire you choose, we think it's key to use the widest size you can and run them at a low air pressure, creating the widest footprint. Forget about running tall skinny tractor tires that you hope will dig through the mud to find traction at the bottom. Sometimes there is no bottom. Wheel choice is easier, as it won't matter whether you run a cast-aluminum or steel wheel, but the lighter the better. You might want to consider running bead locks to support the low tire pressures we're recommending because reseating a tire full of mud is next to impossible.
Axles/Differentials/SuspensionThe best axles for your mud truck are ones that won't break during 99 percent of your wheeling, have good ground clearance, and will let you run a locker/spool in the rear, and a limited slip/selectable locker (so you can steer) in the front differential. If you can keep them together, 10-bolt, Dana 44, IFS, portal, or even Ford TTB axles may have an advantage over a Dana 60 because they don't have huge differentials that hang down and drag through the mud to slow you down. Remember, anything that makes contact with the mud (other than your tires) will slow you down and cause you to get stuck. For rear axles all of the full-float eight-lug axles are fine, but the 1011/42-inch 14-bolt gets bonus points for its strength and low price. Equip your axles with gears that will give you power to spin the tires without hitting the engine's redline.