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Everything (And More) You Need To Know About Mud

Mud Tires Spinning
Ken Brubaker
| Senior Editor, Four Wheeler
Posted April 1, 2011

Tips For Tackling The Goo

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.

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.

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.

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.

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