There’s no need to be floored by terminology if you’ve never looked into how these types of UTV tire constructions are different. Starting with bias-ply tires, these are made the traditional way, with cords that run diagonally across the tire. They’re the most common type of tire available on the market today, and are typically the most affordable. Stiff sidewalks provide a solid load capacity and resistance to damage, including pokey rocks. You can get these in a number of ply ratings.
Radial UTV tires, on the other hand, are made with the cords running perpendicular to the direction of the tread. This seriously improves ride quality, especially when you’re talking about handling quality at speed. As for the ply rating itself, the higher the number, the stronger your tire is. Many riders like to hang out around the eight-ply range, but ten-ply may be better if you treat your UTV like a workhorse.
Tread design optimizes tires for specific conditions. All-terrain tires (medium-depth tread, moderate lug spacing, continuous center ribs) balance performance everywhere without excelling anywhere. Popular designs like STI X-Comp AT or Tusk Terrabite provide acceptable mud traction, comfortable trail riding, and reasonable wear life. Lug depth typically 0.75-1 inch, spacing allows some self-cleaning without excessive noise.
Mud tires use deep lugs and aggressive designs to provide some serious traction in muddy conditions. Widely-spaced lugs shed mud rather than packing solid. Examples include Maxxis Carnivore or similar designs. Trade-offs: terrible on hard surfaces (rough ride, road noise, rapid wear, minimal traction on rock or pavement), heavy (adding rotating mass affects acceleration and ride), and expensive. They're for dedicated mud riders accepting compromises elsewhere or riders with multiple tire sets swapping for conditions.
Trail/hardpack tires (shallow tread, tightly-spaced lugs, continuous ribs) optimize for hard surfaces, rocks, and maintained trails. They provide excellent handling, low noise, good wear life, and a comfortable ride. They're useless in mud (pack solid immediately) and marginal in loose conditions. Examples include STI Chicane or similar sport tires. Sand tires (paddle designs or ribbed patterns) are purpose-built for dunes—unusable on other surfaces. Snow tires (siped tread, soft compounds, narrow profiles) optimize for snow and ice with features like Aramid reinforcement for studding.
Larger tire diameter (say, going from 28" to 30-32") increases ground clearance, changes gearing (effectively taller final drive reducing acceleration but increasing top speed), and potentially requires clutch tuning or lift kits. Speedometers read incorrectly with different tire diameters. GPS speedometers correct this.
Width is going to affect your handling as well as your clearance. Wider tires boost your stability, but they make steering more challenging, which may not matter to the power-assisted rider, but can be a serious issue for others. Depending on your machine, some prefer narrower tires to avoid rubbing and to keep their weight low.
Finally, load rating (weight capacity per tire) must handle your machine's weight plus cargo divided by four wheels. UTV tires typically handle 600-1200+ pounds per tire, depending on size and construction. Make sure that the rating accommodates your use.
How much bigger can I go on tires without needing other modifications?
The rule of thumb here, though it isn’t iron-clad, is that most people can jump up just one size larger than stock without mods. Go any further than this, and expect trimming at the very minimum.
Will larger tires hurt my UTV's performance or reliability?
Larger tires affect performance in multiple ways. Acceleration-wise, a larger tire diameter creates effectively taller gearing, reducing acceleration. Running some chunky tires can also change (not necessarily for the worse) your braking and handling.
What’s the replacement schedule on UTV tires?
The answer varies a ton depending on the tire, your machine, and other details. Some tires (like mud tires) may only make it a thousand miles, while others can chug along for five thousand or more when well-maintained.