EmailFirst, experts say you should understand the kind of tire you need. They caution that you should stick with the size, type and load rating of your original-equipment tires. Because SUVs and light trucks are more likely to be overloaded than cars, load ratings are especially important.
Choose a tire type and size to suit your vehicle and driving conditions:
- All-season tires are best for most owners of light-duty SUVs and trucks. All-season tires have overall good traction (especially in dry conditions), long treadwear and a comfortable ride. They combine the rugged sidewall styling of truck tires with a more car-like ride quality. Some perform well in light snow and ice, but those who live in harsher climates may want to go with a winter tire. Treadwear ratings run between 50,000 and 70,000 miles, and wheel sizes generally range from 15 to 20 inches, with Q, S, T or H speed ratings.
- All-terrain tires are best for moderate winter climates and off-roading. Better off-road and all-terrain performance comes at the expense of ride quality and tread life. Most all-terrain tires are Q-rated, and in addition to standard P-metric (passenger) tire sizes, they also come in LT-metric (light truck) sizes (which carry a slightly higher load rating than corresponding P-metric tires) and flotation truck-tire sizes (which are wider, for better driving on sand and loose dirt). A variety of load ratings are available to match the specifications of your original tires. Many all-terrain tires carry no tread life warranty, though some do.
- Understand tire sizes and speed ratings. You can find out what size tires are right for your vehicle by consulting your owner's manual or by looking on the sidewalls of the tires you're currently using (see below).
- Match new tire specifications to those of your existing tire. You'll need a tire that fits your existing wheels and has an adequate load rating for your vehicle.
Be cautious about plus sizing.
A popular trend is to "plus size" tires and wheels. Drivers buy larger wheels and shorter, wider tires. For example, if your car specifies a wheel size of 16 inches, increasing wheel size by one inch would result in a 17-inch wheel or "plus one" for your vehicle. The tire you buy will then need to have a shorter sidewall, and usually a wider tread, to accommodate the same load and tire diameter.
Although many drivers are doing this for cosmetic reasons -- a larger wheel and lower-profile tire has a sportier look -- some experts say you can gain traction and handling by plus-sizing, because a wider tire can get a better grip. However, Consumer Reports magazine says plus one gains you the most benefit at a lower price. Increasingly larger plus two or plus three wheels and wider tires cost exponentially more and offer less performance gain over plus one.
There are many considerations that will factor into a decision to plus size your tires. First, your car must be able to accommodate the additional offset of a wider tire. You must be sure that the tire's load rating is at least the same as your factory-specified tire. Also, the narrower the tire's sidewall, the more susceptible you are to pothole and curb damage, because wheels can more easily become damaged without the extra rubber. Experts advise buying from a dealer/installer with experience in plus-sizing, who can identify the appropriate size options for your car.
Tire sizing
Passenger tire sizes (called P-metric) and light truck tire sizes (LT-metric) are represented by a ratio followed by a whole number. The ratio comprises the width in millimeters and the percentage of that width that makes up the profile (the distance between the rim and the outer edge of the tire); the whole number is the rim diameter in inches. A tire with a size of 215/60-16 is 215mm wide, 129mm (60 percent of 215) from the ground to the rim and is intended for a 16-inch wheel.
Tire manufacturers use letters to represent the maximum speed at which a tire should be driven. There are about 20 different speed ratings, but the most common for SUV and light truck tires are Q (up to 99 mph), S (up to 112 mph), T (up to 120 mph) and H (up to 130 mph). Experts say that even if you have no intention of driving at speeds of 130 mph or more, tires with a high speed rating are also better performers at more mundane speeds.
Mud tires
Mud tires are best for extreme driving on large rocks and deep mud. Mud tires are not suitable for most drivers, because they're louder and ride more harshly than all-season or all-terrain tires on paved roads. Some are greatly oversized to increase their ability to go over rocks and ruts, which raises a vehicle's center of gravity and makes it more prone to tipping over in normal driving. Among the mud tires on the market that also get high marks for on-road behavior is the Firestone Destination M/T (*est. $130). This tire confidently handles mud, rocks, snow and rain, according to owner reviews at Tire Rack and Offroaders.com. It is also less expensive than other highly rated mud tires. Although this tire gets compliments for looking particularly tough, it comes in normal (not monster) sizes.
For a truly extreme mud tire, Petersen's 4 Wheel & Off-Road magazine gives its highest honors to the Interco Super Swamper Bigger LTB (*est. $480). In a head-to-head test of seven extreme off-road tires, editors found the Bigger LTB (so named because its 47-inch diameter is bigger than Interco's regular LTB) the best of the pack for all-around performance on big rocks, loose rocks and deep mud.