How Mud Tires Work
Do you have a truck or a 4×4? Have you ever tried driving through mud or going off-roading on all-season tires? If you’re an enthusiast driver then you know the value of good mud tires, also known as mudders, these tires can make or break your adventure. But how do they work? There are two key parts to every mud tire that separates regular tires from mudders, tread pattern and size.
The Rubber Manufacturers Association (RMA) creates the standards for all motor vehicle tires. Tires rated for mud and snow use will have one of the following markings on the side of each tire: MS, M+S, M/S, or M&S. To achieve this classification the tire has to meet certain design criteria. It must have multiple pockets or slots in one or more of its treads that extend to the center, a minimum of ½ inch. The tire also needs to have a cross-sectional area across of 1/16 inch or more and an angled tread pattern of at least 35 degrees and no more than 90 degrees toward the rotational direction. The last requirement is an open void area of 25 percent of the tire’s surface area. Many mud tires far exceed these minimum requirements in their tread pattern.
The angled tread pattern, or lug, and open void area are key in providing grip and cleaning the tire. Lugs or in some mud tires, paddles, provide traction in muddy surfaces. Mud fills in the open areas and provides resistance and traction to keep you moving. The size and type of lugs/paddles vary – there are hundreds of brands and styles. The bigger and more aggressive the tread, the better the tire is designed to work in mud. As the tire rotates out of the mud the angled tread is also designed to let the mud escape. If thick mud is stuck between the lugs you might start to loose grip and the tire will just spin in circles. This feature is called self-cleaning lugs and is designed to clean the tire with each rotation.
Another feature many mudders have is sidewall lugs. Since the tire usually sinks in the mud the more areas that can provide grip, the better, and that includes side wall lugs. Most off-road tires and mud tires have strong sidewalls to survive damage from rocks and debris. Also a stronger, stiffer sidewall will help support the tire if you’re running lower psi – which can help add more traction off road.
The second key point that helps mud tires is their size. In this case bigger is better. Bigger tires provide better float, they get you higher out of the mud – if your entire tire is below the mud, they cannot clean and then there is probably too much resistance working against them. So for mudding – bigger is better. But how big can you go? That depends on your vehicle and if you’ve done any suspension modifications. Many off-roaders install body lifts or suspension lifts to allow larger tires to be installed.
Department of Transportation (DOT) approved mud tires can get up to 54 inches in size according to Doug Shaw, Director of Parts at GoAuto. He also states that each state has their own motor vehicle laws, and they all vary, be sure to check what is legal in your area. In standard sizes mud tires can range from 30” on up. Using bigger tires is extremely helpful when mudding – they provide better clearance, improve grip, and can help you float through mud better.
Tradeoffs to Mud Tires
The first trade off to mud tires is the more aggressive the tire the worse they handle on pavement. Since they have big open voids to help clean they have a small contact area with the road. The second tradeoff is size – while it’s a benefit off road, on road it raises concern. Bigger tires are more expensive. They can cost more than $500 per tire, while you find cheap mud tires, they are usually more expensive than regular all-season tires. Bigger tires also put more strain on your engine and drivetrain, this results in lower gas mileage and more wear. For many people these tradeoffs are worth the performance advantage mud tires give. There is a right tread pattern and size for every driver out there.
About the author: James is an auto enthusiast who writes for a Canadian dealer network willing to do whatever it takes to help with your automotive needs. Stock images provided by Shutterstock.com