Why Tires and Wheels May Be the Most Important Part of Off-Roading

Tires are unequivocally the single most important part of any car. After all, the most powerful engine in the world, the best possible suspension setup, and the finest brakes with infinite bite mean zilch if the tires just spin without providing any grip.

This fact applies to commuter EVs, semi-trucks, and race cars alike—but might be most obvious while off-roading. That’s because leaving the tarmac reveals how much tires serve as the first part of the entire suspension system. It's why off-roaders air down to simultaneously improve ride comfort, reduce impacts for the entire vehicle, cut the chances of a flat tire, and enhance grip and float in various traction scenarios.

Airing down off-road usually involves dropping to at least 25 psi, though some off-roaders run as low as 4-6 psi, depending on the situation. While fully aired down, beadlock capable wheels help keep the tires on the wheel—which is part of why wheel choice also comes into play when four-wheeling. Cracking a rim, tearing off a badly placed valve stem, or entirely de-beading from the wheel all sound (and are) far worse when you're stuck way out in the middle of nowhere.

The choice of wheels usually comes down to stud pattern, stock aluminum versus basic steelies, and budgetary considerations. Forged aluminum can cost a pretty penny—but investing in bigger, better tires reduces the beating a wheel takes. So, what should every off-roader consider when selecting a tire? That’s a more complex question than even most experienced four-wheelers realize. Here's a quick, essential tire primer to explore the options and steer you toward the perfect set.

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Typical Mistakes When Choosing Tires

Making the proper tire choice first requires making an honest assessment of what kind of off-roading the vehicle in question will actually be doing. Will it be cruising through town and highways most of the time, or seeing its share of short trails and graded roads along with some real rock-crawling? The right selection for a dedicated off-roader that never sees asphalt will be entirely different than all the above, too. Every specific type of use case-points to a different type of tire.

The popular opinion of simply buying the biggest tire possible reveals many fallacies about general tire knowledge. While increased diameter might increase ground clearance, it also reduces the amount of torque that an engine can deliver to the ground. Larger and wider tires also may not fit properly within an SUV or truck’s wheel well without rubbing with the steering wheel turned, or even during hard suspension dips.

Tire width also typically brings up plenty of debate among off-roaders. Most agree that wider tires increase the area of the rubber’s contact patch with the ground, but narrower tires flex more in a longitudinal direction, which increases traction too. The tire’s environment plays a big role here, too. In sand and snow, wider tires may allow better “float” through the slop and perform better when turning at higher speeds. But narrower tires can hold better grip in a straight line, while some even offer designs that intentionally flex at the shoulder to increase width at low pressures, too.

All-Terrains vs Mud-Terrains

What about the difference between A/T (all-terrain) and M/T (mud terrain)? These two popular terms generally refer to different rubber compounds, levels of internal reinforcement, and tread design (including sipes). From a visual standpoint, M/T tires typically feature more aggressive treads with bigger, more widely spaced blocks to better grip rocks, sand, mud, and snow. Mud-terrains generally use more internal ply bands, both to support the tread and the sidewalls.

If beefier M/T tires definitely look the business, the trade-off here comes down to distracting humming sounds (that can approach a deafening roar while on-road at high speeds) as well as rolling resistance and unsprung weight—all combining to negatively affect fuel economy, power delivery, and suspension performance. Mud-terrains will also cost more and wear out faster in just about any environment versus a comparable all-terrain tire.

LT vs P-Metric Tires

Next up is a differentiation in types of tires that most off-roaders never take into consideration: P-metric versus LT tires. Simply put, P-metric indicates Passenger tires and LT means Light Truck. But as usual, those simple descriptions lead to some unexpected ramifications. Similar to M/T tires, LT tires typically feature more internal reinforcement—but unlike mud-terrains, they offer more durable rubber compounds that will last for a longer service lifespan.

Why not go for LT-metric on every off-road vehicle? Well, P-metric means softer sidewalls and softer rubber compounds, both of which translate to more comfort in just about every driving environment. Counterintuitively, P-metric tires will also flex more when aired down, which also increases comfort—but, more importantly, reduces the risk of flats because the tire can mold around rocks and obstacles better. Critics will point out that the sidewalls may tear more easily, which requires more cognizance on driving style.

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Load Range Explained

Taking a dive into the deep end of tire history requires an explanation of Load Range ratings. To a certain extent, Load Range is related to ply ratings, and is also somewhat outdated as modern tire technology improves by leaps and bounds. Load Range serves as a general indicator of a tire’s inner construction, ability to carry weight (such as overlanding gear or a trailer), and maximum allowable inflation pressure.

Many large trucks call for Load Range E tires from the factory, which means at least 100 ply construction (or 10 bands of inner reinforcement in the tread area) and up to a max of 80 psi. But modern tires typically use a lower ply number, built out of more durable materials including kevlar and carbon fiber. While sticking with OEM recommendations is always a good idea, there’s a strong case to be made that Load Range should possibly go out the window for most vehicles other than true work trucks and tractor-trailers.

The Mythical Snow Tire Symbol

Yet another confusing tire rating should also come into play—at least a bit—for anyone who expects to do any off-roading in severe whether. This is the mythical 3-Peak Mountain Snowflake symbol that appears on dedicated winter tires, as well as A/T and M/T tires from some manufacturers. In short, the 3PMS logo means that the tire passed government testing in cold and slippery situations.

A caveat with the 3PMS test is that it often falls short of expectations. Earning the certification simply requires beating a comparison test, in straight lines only, against a Michelin winter tire never sold to the public. No cornering demands—which seem important if a car loses traction in snow or on black ice—as well as no durability testing enter the mix.

Does Anyone Actually Need Off-Road Race Tires?

The last type of tire to consider, for almost everyone other than true desert rats, is a dedicated race compound. Sort of like M/T squared, off-road race tires use much more ply in the tread and sidewall with compounds designed to take an absolute beating. Think Baja 1000 trophy trucks blasting around at 150 mph, or King of the Hammers Ultra4 rock crawlers bouncing off cliffs. These are not typical off-roading or overlanding demands by any means—and they lean toward environments and situations where tires take a heavy beating before getting swapped out fast. True race tires will deliver terrible longevity, aren't street-legal, and can often be straight-up dangerous on asphalt. The few rigs that actually need them, definitely do need them.

All this tire talk offers plenty to consider. It's a ton of details that could be contorted into a large Venn diagram, but the myriad options and ratings arise because tires are truly the most important factor when preparing a vehicle for off-roading—along with a steady hand and a clear mind when you're out there. Just don’t forget that matching spare.