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  • Four Wheeler

Tips for building a mud truck

Posted in How To: Tech Qa on April 13, 2016
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Photographers: Ken Brubaker

One of the oldest and most enjoyable ways to spend time off-road is wheeling at your local mud put. Sure, mud isn’t for everyone, but it’s something that all off-road enthusiasts encounter to some degree. For the hardcore, it’s as competitive and serious as it gets. While the recreational side of the off-road hobby see’s the most mud grins, the slick dirt is also something many workers deal with as part of their daily commutes. From farms and work sites across the nation, getting bogged down can cost you more than a little time.

Here we’ve compiled some sure-fire ways to keep your vehicle moving and, more importantly, surviving in the wet dirt. Some of these items are better suited for competition-only vehicles, but most apply to any one who sees mud (or water) on a regular basis. Have some tricks that you think we missed? Drop us a line with your home-made solutions at

You can’t expect your 4x4 to survive in the mud without the proper tires. Mud terrains come in all shapes and sizes and can get pretty extreme at the competition level. Just having a conventional mud-terrain radial is a great way to keep your rig moving. When looking at a mud-terrain tire, you’ll want to focus on a few key attributes. The first is tread spacing. The larger the gap between the lugs, the less chance the tire will get clogged. Additional features such as kick-out bars that help eject debris between the lugs are also very effective. You will sacrifice a little pavement performance with some of the more extreme mud tires, but there are plenty of mud-terrain radials that work great on-road and off.

In the world of mega trucks, tractor tires reign supreme. This is largely due to the ability to get them in monstrous sizes. Of course, the huge tread size and spacing make them excel in the mud, but they won’t be easy on your equipment. Ag tires may all look very similar from one to the other, but like light-truck tires, there are a range of tread compounds, patterns, plies, and construction. The most common tall-and-narrow tractor treads are rice-and-cane tires, which are commonly referred to as R1 and R2 tires. Don’t forget to factor in that you’ll likely need a custom set of wheels to run the off-road-only farm knobbies

Spending a lot of time in mud is especially hard on your axles and brakes. Regular differential gear oil changes and greasing of the axle where possible will prolong the life of your components. If you have drum brakes, however, we suggest investing in a disc-brake conversion. Drums tend to get packed with mud off-road and can make their stopping ability almost disappear. Swapping to a disc set will allow the brakes to remain unclogged while extending the life of the components.

We’ve witnessed modified 4x4s become stuck in just a few inches of mud on flat ground thanks to open differentials. Installing differential lockers is the only way to get all of the tires reliably fight for traction. Unlike wheeling in the rocks or traction-rich conditions, there isn’t a lot of potential for component binding. This means you can get away with running automatic lockers such as a Detroit Locker. In more dedicated off-road rigs, you can get away with running even more aggressive traction aids such as spools. For those still using their mudders as a daily driver, we strongly suggest looking into selectable lockers such as an ARB Air Locker, which gives you the best balance of off-road locking action and great street manors.

We’re all for a keeping a low center of gravity in our wheeling rigs, but you’re going to need a bit of lift to keep your rig out of the muck. Look for a suspension system that offers increased lift height with improved suspension features such as nitrogen-charged shocks and long-travel springs. You’ll want plenty of up travel since your rig is more likely to take big hits at speed in the mud, so avoid overly stiff leaf springs and coils.

Clean air is critical for your rig’s survival. Items such as snorkels can drastically raise the intake levels of the vehicle, thereby reducing the risk of ingesting water. Remember, it only takes a few ounces of water to completely hydrolock your engine.

For more dedicated mud-runners, most opt to route the engine’s air intake inside of the cabin. We’ve even seen it plumbed over the cab and in the bed on some applications. The main goal is to have the intake protected, while not restricted.

Wheel speed is incredibly important when driving in mud. Unlike crawling in the rocks, where you need a slow and steady approach, mud takes momentum. The faster the tires move, the easier they will eject mud and get you down the line. If your truck doesn’t have the power to get through the mud in high range, we suggest installing a set of numerically higher differential gears. Yes, you can use low range in the mud, but it’s going to reduce the wheelspin potential and ultimately the speed of the vehicle. In vehicles with manual transmissions, you can often get a little more power out of the rig by engaging low range while driving in a higher transmission gear.

Mud is just wet dirt, so you’ll need to plan for water. This mean waterproofing as best you can. Sealing off delicate electronics with silicone is one of the oldest and most effective ways at preventing electrical failure off-road. Silicone is also handy for sealing up your rig’s air intake.

While we mentioned routing your engine’s air intake safely out of harm’s way, you’ll need to do the same for the rest of your vehicle’s powertrain. Your vehicle’s transfer case, as well as its differentials, have breathers that can easily be extended. You can even purchase breather relocation kits such as this one from ARB.

High revs and low speed are a sure-fire way to get your engine to run warm. Consistent mud wheeling can often clog the radiator, leaving you in an over-heating situation. For more dedicate mud-racers and boggers, moving the radiator to the bed is a great cooling solution. This will require some clever plumbing as well as electric cooling fans, but is otherwise a very inexpensive and straightforward upgrade.

There seems to be two schools of thought when it comes to post-mud cleanup. One is to wash the vehicle off immediately afterwards. Another post-mud ritual is to actually let it dry and take it off in large, dry sections. Yes, he’s using a hammer to beat the mud off. It’s not something we would want to do to a new Wrangler, but we’ve seen it work on a dedicated mud rig.

Shedding as much weight as possible will always help you move farther in the pit. Ditching extra seats, removing sheetmetal, and opting for lighter body panels such as fiberglass can net tremendous results.

Spending frequent time in the mud will destroy your rig’s carpet. We suggest removing it completely and using a roll-on or spray-in liner. Don’t forget that you may need to make or remove the existing drain plugs as water will easily find its way in once you are properly submerged.

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