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Everything (And More) You Need To Know About Mud

Posted in Project Vehicles on April 1, 2011
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It really doesn't matter whether you like mud or not. Chances are you'll eventually have to navigate it with your rig.

Mud comes in many forms. There's the thin, grease-like slime that forms on dirt after it rains or after snowmelt. This mud can be like driving on sheer ice and can make a four-wheel-drive vehicle embarrassingly helpless. Resistance isn't the problem, it's just a complete lack of traction and control. The last time we were on mud like this was near Telluride, Colorado, on Last Dollar Road after a summer monsoon. We were in a four-wheel-drive rental SUV and the complete lack of traction, along with mud-caked street tires, forced us to inch our way at single-digit speeds in an effort to keep from sliding off the mountainside. We have also witnessed the hidden power of this type of mud in Wisconsin, where we watched a well-built, but all-terrain-equipped pickup truck flounder in place helplessly on a flat trail for seemingly no apparent reason. On the flip side, there's the deep, rutted, glue-like mud that can swallow a vehicle whole. This mud often has no "bottom," or if there is one, it's far deeper than the distance from the contact surface of the tires to the axles or frame. This means the rig will simply sink until the added resistance of the dragging axles or frame will effectively stop all forward progress. Both of these types of mud can be found just about anywhere on this sphere we call home, and they're as much a part of nature as oxygen.

Your four-wheel-drive rig affords you a level of capability not available to other vehicles. But even so, from the factory its mud competence is limited, and traversing the goo requires you to think of your rig as a foundation to be built on. So with this in mind, we've put together a few tips to help you modify your rig to handle the mud. To what level you choose to modify your rig depends on how often and on what type of mud you travel. Hopefully these tips will help you make your mud experience a more enjoyable one, because eventually the goo will find you.

The result of mud tires, wheelspin, and horsepower is forward momentum.

Mean Donuts
If there's one item that can radically improve your rig's capability in the mud, it's a set of mud tires. A good set of mud tires will have an aggressive tread pattern with a self-cleaning design that will shed mud as they spin. Less aggressive street-biased tires will simply load up with mud, and traction capability will be lost. They'll end up looking like glazed chocolate donuts, but won't taste as good. Flotation is also important in the mud and is accomplished by adding wider tires. Adding width enlarges the contact patch, and thus helps decrease the tire's natural tendency to sink. How much width to add is determined by a number of factors, including your vehicle's weight and available power. You can also add width to your tires by simply airing down. Tire height also plays a factor in plying the mud. Among other things, a taller tire helps to create more space between your vehicle's axles and the mud, which means you'll be able to traverse deeper mud without the axles acting like an anchor.

Non-aggressive tires can load up with even thin, greasy mud, which can result in a lack of directional control as this Dodge pickup owner found when he slid into a ravine and got hung up on the rear axle.

Lock 'Em Up
If you have open differentials on your rig, you really have only two-wheel drive when you have your rig in 4-Hi or 4-Lo. Clearly, having only 50 percent of your wheels pulling through the mud isn't ideal. The solution is to install locking differentials. There are a few schools of thought in this area. Some feel that a rear locker/front limited-slip is the hot ticket for handling purposes. Others feel that locking both the front and rear axle is the magic. Others believe that selectable lockers, or a combination thereof, are the way to go. Ultimately it doesn't matter what you choose-just choose to get lockers because you'll see a vast improvement when you get all four wheels pulling.

An ample source of mud-free air is required for an engine to run, so high-mount air intakes are often used in mudding. This SUV owner also made sure his rigs engine could exhale by installing a high-mount exhaust.

Right Ratio
If you've added larger-diameter tires to your rig, you may have noticed a decrease in power due to the affect they've had on your vehicle's gearing. Deep mud will compound the issue. You see, deep mud has a significant amount of resistance. This resistance saps engine power, and entering the goo with the improper gear ratio means you're quickly going to find that the lack of power you had on the street is amplified. If you can't get those mud tires spinning, they won't clean, and it takes power to spin those meats. The fix is to regear your rig to compensate for the larger-diameter tires. Any of the aftermarket gear manufacturers can recommend a ratio that will work with your tire diameter.

Get Beadlocked
Lowering tire pressure is a good way to increase your tires flotation. And flotation, as we discussed earlier, will help you navigate the mud. Problem is, tires at low pressure don't really want to stay on the wheels-especially when you're pouring on the coals and sawing the steering wheel back and forth. Dragging a rig out of the mud with a tire dangling off the wheel isn't fun, and getting the mud-filled tire cleaned out and back on the wheel is even less fun. Some OEM wheels, like those found on the Dodge Power Wagon, are specially constructed to keep the tire bead set on the wheel at low pressure, but these wheels are rare. The solution is to outfit your rig with beadlock wheels. With these wheels, you can get crazy in the mud with minimal tire pressure without worrying about peeling a tire.

Low tire pressure can be your friend in the mud, but it can also be the catalyst for a lot of work when a tire peels from a wheel. Beadlock wheels can help keep this from happening.

Get Lifted
We all know that oftentimes one modification to a rig necessitates another. This is often referred in a highly technical term known as the "domino effect." If you want to fit larger tires, as covered earlier, you will need to install a suspension lift kit to make room. This is a good thing, actually, and when it comes to deep mud, it's almost mandatory. There's a reason why trucks used for mudding are often mega-tall. A lift kit will move your vehicle's body and frame further from the mud, thus making it more capable of traversing deep mud while decreasing the likelihood of forward momentum-impeding contact. The idea is to only have your tires in the mud, nothing else. Mud isn't like rockcrawling, where off-camber travel is the order of the day, so the higher center of gravity isn't as much of a concern.

Serious mudders, like those found in Florida, overbuild as a rule. This wicked '96 Dodge Ram has a 525ci engine, TCI manual valvebody transmission, NP200 transfer case, and 21/2-ton Rockwell axles.

Got Power?
Thin, grease-like mud isn't going to require gobs of horsepower, but deep mud is a different story. When you add a set of large, heavy, grippy tires, and you try to push them, and your vehicle, through the resistance of deep mud, you're going to need power. Easy-to-install items that improve horsepower include free-flow intakes, performance chips and cat-back exhausts. If you really want to get serious, consider a supercharger or nitrous injection.

Extreme mudders know what works, and massive amounts of lift and ag tires are tops on the list.

Beef the Drivetrain
Momentum and wheelspeed are the order of the day in deep mud. "Crawling" deep mud doesn't work. With that said, you need to address every aspect of your drivetrain to make sure it's up to snuff and capable of prolonged hard use. For instance, your engine will be working much harder, thus generating more heat. Hence, you need to ensure your cooling system is in top condition. Also check it often while wheeling in mud to ensure it isn't clogged. Serious mudders often mount the radiator in the bed of the truck to protect it from clogging. Also consider beefing items like axles and U-joints, as these too will be subject to significant stress. Hardcore mudders say that it's always a good idea to overbuild, which is why it's not unusual to see 21/2-ton Rockwells under large-tired rigs that spend a lot of time in the mud. And don't overlook your steering! Among other things, the torque going to the frontend puts a lot of pressure on items like the tie rod as the tires try to "toe in" under load.

This fullsize Chevy proves that a truck doesn't have to be mega built to be capable in the mud. The truck sports mud tires and a mild lift along with a winch in case it gets stuck.

Mud is dirt mixed with water. Oftentimes, deep water blankets the mud, so waterproofing should also be high on your priority list. The last thing you need in the middle of a deep mud crossing is a dead engine due to wet electronics or from ingesting water. The best course of action is to apply basic waterproofing techniques. Make sure electronics are sealed, vent lines are high-mounted, and air intakes are well above the water line (yep, a snorkel would be a wise addition). Some hardcore mudders even route the exhaust high on unlifted rigs so that the goop can't get into the exhaust system.

Don't Forget About Recovery
Finally, even with the best preparation, mud has a way of winning. When this happens, and you churn to a stop in the muck, you'll need easy access to your recovery supplies. Whether in deep mud or the thin, greasy stuff, you'll appreciate things like easy-to-access tow points. If you have a winch, consider synthetic rope because it floats.

There's never a good place to be stuck in the mud, but if you're prepared, the recovery can be quick and painless. This truck owner is probably wishing he had attached the tow strap before he hit the mud.

Where To Get Parts
The aftermarket is saturated with mud-friendly parts. If you're looking for one-stop shopping peruse the advertisers here in Four Wheeler. Some specialize in selling a wide range of products while others concentrate on a specific area like drivetrain, tires, or recovery. In almost every case, each advertiser lists its website address, so you can simply go to their website and read up on their products. Heck, many of them even let you order parts directly or, at the very minimum, guide you to the nearest distributor.

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