Tire Speed Rating and Why It Matters
The tire speed rating is the maximum speed tires can safely carry a load (the original weight of your vehicle plus whatever’s in it) for a sustained amount of time in ideal conditions. The rating is molded on the tire sidewall, signified by a letter or two, usually after the load index number. Together, the load index and speed rating form the service description.
Each letter in the speed rating represents a maximum speed based on a standard chart.
The main things to know:
- Generally, the higher in the alphabet a tire is rated, the better it will manage heat and faster speeds. There’s an exception for the H rating; read on for why.
- Your actual speed capacity may be less than a tire’s rating. The rating indicates a new tire’s performance in tightly controlled lab settings, not the open road. Tire condition, inflation level, extra cargo, road surfaces and weather are everyday limits that play into a tire’s maximum safe speed.
- If you have tires with different speed ratings, the limit of the lowest rated tire is the fastest you can drive and stay within your tires’ capability.
- The most common ratings are S and T (sedans, minivans, light trucks); H (some passenger cars, sports cars, coupes, some light trucks); N, P, Q and R (light trucks); and V, W and Y (high-performance cars). Most winter tires have Q, S or T speed ratings.
Tire Speed Rating Chart
Here are the symbols and translation into mph:
SPEED SYMBOL SPEED (mph) SPEED SYMBOL SPEED (mph) SPEED SYMBOL SPEED (mph) A1 3 E 43 S 112 A2 6 F 50 T 118 A3 9 G 56 U 124 A4 12 J 62 H 130 A5 16 K 68 V 149 A6 19 L 75 ZR* W 168 A7 22 M 81 Y 186 A8 25 N 87 (Y) Above 186 B 31 P 93 *For tires having a maximum speed capability above 149 mph, a ZR may appear in the size designation... above 186 mph, a ZR must appear in the size designation, including a Y speed symbol in brackets. C 37 Q 99 D 40 R 106 SPEED SYMBOL SPEED (mph) A1 3 A2 6 A3 9 A4 12 A5 16 A6 19 A7 22 A8 25 B 31 C 37 D 40 E 43 F 50 G 56 J 62 K 68 L 75 M 81 N 87 P 93 Q 99 R 106 S 112 T 118 U 124 H 130 V 149 ZR* W 168 Y 186 (Y) Above 186
*For tires having a maximum speed capability above 149 mph, a ZR may appear in the size designation... above 186 mph, a ZR must appear in the size designation, including a Y speed symbol in brackets.
Note: Yes, the H rating is out of place and that’s not a typo. When tire speed ratings were first developed in Europe in the 1960s, there were only three ratings: S, H and V. As tire technology developed and new speed classes were introduced, the ratings table expanded to include the full alphabet. But the letter H kept its original speed rating of 130 mph, so it sits later in the chart.
Z-rated tires will sometimes have the letters ZR embedded with the tire size information instead of in the service description.
How are Speed Ratings Determined?
Tire manufacturers determine a tire’s capacity for heat and speed using a testing machine. Usually testing is done to meet ECE (Economic Commission for Europe) standards, so the scale is based on kilometers per hour (km/h). A more rigorous test is sometimes done to meet SAE (Society of Automotive Engineers) standards.
- For the ECE test, the tire is properly inflated and mounted on a wheel attached to a testing machine in a room that’s heated to 77 degrees F.
- The tire is pressed against a metal drum with enough pressure to simulate a realistic load.
- Starting at a speed 40 km/h lower than the proposed rating level, the tire is spun for 10-minute increments at higher and higher speeds, until it reaches the target speed.
- The tire spins for 10 minutes at the target speed.
- It’s then removed from the machine and inspected for any failures, like separation of tread components. If it’s intact, it passes the speed rating.
- Sometimes an SUS (step-up speed) test will be added after the tire performs at the target speed rating. Speed is increased until the tire fails.
- If the tire is being tested at the SAE standard, it’s required to run for an hour at target speed in a room heated to 100 degrees.
How Much Does It Matter for Your Driving & Tread Life?
Tires with higher speed ratings offer handling benefits that thrill some drivers, but there are tradeoffs. Since they’re usually made with softer rubber compounds and stiffer construction they offer better cornering, stopping power and steering response. But expect a little less ride comfort, lower performance in cold conditions and shorter tread life. Consumer Reports found that some H- and V-rated tires didn’t last as long as those rated for lower speeds, wearing out closer to 50,000 miles than 60,000 miles.
What Rating Do You Need?
Even in states where rural speed limits are 75 mph, most drivers will stay well below the speed limitations of H-rated tires. Commuters and family car drivers will likely be quite satisfied with S or T tires.
If you’re a spirited driver with a high-performance car, you may be happier with V, W or Y tires. Light truck drivers will be looking for symbols N, P, Q, R, S, T or H.
If you’re replacing tires and think you may want a lower- or higher-speed-rated tire, it’s best not to mix and match. When mounting differently rated tires, techs prefer to put the lower-speed-rated ones on the front to prevent oversteering. This can conflict with the best practice of putting the tires with the most tread on the rear, which is important for wet traction.
Get tires with the same speed rating. If you don’t, remember that the maximum mph is limited to the tire with the lowest speed rating.
Tire speed rating is not like a speed limit posted on highway signs. It’s based on lab simulations and doesn’t account for real-life factors that determine true tire capability: Are the tires fully inflated? Is your vehicle properly aligned? How hot is the road? Have you ever had a flat repaired? What’s the age and state of the tread?
Don’t use the rating as a guideline for the top speed you can drive. If you’re carrying a heavy load, have a tire that’s been patched after a puncture, or low on air, your tire’s speed capacity will be much reduced. For safe driving, keep your speed at the posted speed limit — or below, when road conditions or the weather aren’t ideal.
Important Notice: The information provided above is derived from sources deemed reasonably reliable. The operation of your vehicle, or the replacement of your vehicle’s equipment, may be different than for a typical vehicle. Please consult your owner’s manual for specific warnings, notices, and other advice relative to the subjects addressed.
How to Choose the Best Tires for Your Crossover or SUV
When it comes to putting the right set of tires on your SUV, there are a lot of choices. The best place to start is with the size of your SUV or crossover, where you’ll be doing most of your driving (in the mountains or on the highway), and the weather conditions you’ll face throughout the year. We’ve put together some quick answers to help you decide on the best SUV tires for your terrain and driving habits.
Yes, You Can Put Truck Tires on an SUV
However, it can get complicated depending on the size of your SUV. Standard passenger tires are often installed as original equipment on most compact and midsize or crossover SUVs. Midsize SUVs include models such as the Honda Pilot, Ford Explorer, and Toyota Highlander. Smaller SUVs range from models like the Toyota Rav4 to the Subaru Crosstrek. Some examples of large SUVs include the Toyota Sequoia, Nissan Armada, and the Ford Expedition.
If you have a full-size or larger SUV, there may be multiple truck tire options available for your specific needs. If you want a set of tires you can use year-round and in just about any weather conditions, upgrading to a more rugged tread design may be a good recommendation. Your local Les Schwab can help you narrow your choices and get the right set of tires for your needs.
H/T (Highway Terrain) Tires for Daily Commute and Highway Driving
There is a good chance your SUV came with a set of H/T tires. These tires are designed for highway driving in both dry and wet road conditions. One of the best choices to maximize your SUV’s highway performance in any season, and enjoy a smooth, quiet ride is with a set of Back Country Touring H/T tires.
Just be aware that H/T tires aren’t designed for extreme winter weather conditions, or prolonged use on gravel roads or in off-road conditions. If you plan to take your vehicle into the snow or off the highway, it may be best to move to an A/T tire for better traction and performance.
Why Choose H/T Tires
A/T (All-Terrain) Tires for Winter Driving and Off-Road Conditions
If you occasionally drive in the snow or other winter conditions, as well as dirt and gravel roads, A/T tires are a good option. Some A/T tires are designed for improved all-weather, year-round driving. The deeper tread design, like that of the Open Range A/T, is designed to take on snow and other winter conditions, as well as off-road while maintaining a quiet ride on the highway. However, they may not be as quiet as a set of H/T tires.
Why Choose A/T Tires
Plan on driving to the mountains this winter? Check out a set of Himalaya SUV for your vehicle. These tires are designed to help you stay on the road in the harshest winter weather conditions. Plus, they can be used with or without studs for added grip.
Get Your SUV Tires at Les Schwab
Stop by your local Les Schwab for answers to all of your SUV and crossover tire questions. Our experts will be able to recommend several tires based on your driving needs, budget, and safety concerns.
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Choosing the Right Off-Road Tires
Throughout the West, adventure is continually calling those with SUVs, crossovers, and trucks to explore and tackle the great outdoors. Whether you’re into mudding, overlanding, rock crawling, or winding your way along miles of back-country gravel roads, choosing the right set of tires starts by understanding what they’re designed to tackle.
The Basics of AT and MT Tires
AT (All-Terrain) and MT (Mud-Terrain) tires have a lot of similarities, but each are specially designed for different terrains. AT tires are far more aggressive than HT (Highway Tires), but provide less traction in mud and off-road driving than a set of MT tires. MT tires give you traction in extreme off-road conditions, including dirt, mud, gravel, and rock.
Get some quick advice right now with our helpful Q&A to buying tires.
Why Choose All-Terrain (AT) Tires
The right set of AT tires can add a rugged appearance to just about any SUV or light truck. Beyond good looks, durability, and dependability for your daily commute, you also get more space between lugs and open shoulders for increased traction, including rain and winter weather conditions. And because the tread blocks are varied, AT tires are often quieter on highways and city streets than MT tires.
The Bottom Line: If you don’t plan on navigating anything worse than a rutted gravel road or sandy beach on your weekend hike or camping trip, AT tires could be your best fit.
- More aggressive looks
- All-weather traction, including wet and winter conditions
- Long tread life
Start With These All-Terrain Tires
Digging Into Mud-Terrain (MT) Tires
MT tires are designed for extreme off-road conditions. The key here is the term “off-road.” These things were first invented by the U.S. military, which means they can take you almost anywhere. The tires are created with a tread pattern that utilizes huge spaces between the tread lugs and open-shoulder design to give you increased traction. Plus, MT tires give any vehicle a rugged, aggressive look, whether your vehicle is lifted or already offers plenty of clearance.
The Bottom Line: If your outdoor adventures have you facing mud, dirt, gravel, hardpack, rock, and other extreme off-road conditions, Mud-Terrain (MT) tires should be your first choice.
- Aggressive looks
- Maximum durability for rough terrain
- Ultimate traction in mud, dirt, rocks, and gravel
Explore These Mud-Terrain Tires
Should You Get Four or Five Tires
A rugged and tough set of AT and MT tires can take you almost anywhere, but flats still happen. That’s why it’s important to have a full-size, AT or MT spare along for the ride. That way you can get back home without help from a friend or rescue rig.
Get the Right Tires for Your Adventures
We’ll show you all of your options, help you decide between All-Terrain (AT) and Mud-Terrain (MT) tires, and send you off to plan your first outing of the season. Stop by today or schedule your appointment now and we’ll block out some time just for you.
Why Worn Tires Are Less Safe
When it comes to safety on the road, your tires are one of the most important parts of your vehicle. And the tire tread on those tires is where the rubber literally meets the road! However, as you drive, more of that tire tread disappears. Over time, that can add up to less stopping power and maneuverability in different weather conditions. It can also mean more punctures resulting in air loss. We’ve compiled some of the reasons why worn tires are less safe and when you should replace them.
Tires Equal Performance
According to the National Highway Traffic Safety Administration, nearly half of all vehicles on the road have at least one half-worn tire. That means the depth of the tire tread is half of what it was when the tire was new.
Tire tread depth on a new car tire is usually around 10/32 to 11/32 inches. Light trucks are between 11/32 and 19/32 inches. For a car, half-worn would mean the tire tread depth was around 6/32 inches. Due to safety concerns, many states require tires be replaced when they reach 2/32 inches, which is considered bald.
Measuring Your Tread
Loosely measuring the tire tread depth on your tires is easy. All you need is a shiny penny. Check out Tire Tread and the Useful Penny Test to learn how to measure yours. Or get yourself a tread-depth gauge, which is far more precise. To help you spot bald tires, manufacturers have added horizontal rubber bars at the base of tire tread grooves. If those molded horizontal bars are flush with the surrounding tread, then your tires are more-than ready to be replaced.
At Les Schwab, we recommend you get new tires before they reach 2/32 inches. Here’s why.
Tire Tread Keeps You in Control
As tires lose tread, the sipes or channels in between the tire tread disappear. This means you have less grip on snowy and icy roads. It can take far longer to accelerate with half-worn tires, and can dramatically reduce your stopping distance.
In the rain, you have a greater chance of hydroplaning at higher speeds. Plus, half-worn tires don’t deliver the stopping power of new tires in the rain and standing water.
Tire Tread Repels Objects Better
The lower your tire tread gets, the easier it is for nails, screws, and other tire-piercing items to ruin your day with a flat tire.
Pro Tip: Check Your Tire Tread Every Other Month
Measure and look for reduced tire tread every time you add air to your tires. For most folks, that’s every other month or so. Or you can just swing by your local Les Schwab and we’ll check the air pressure and your tire tread depth for free. That includes looking for cracks, cuts, or bulges in the sidewall, and uneven wear. Schedule your appointment now or stop by before your next road trip down the highway or into the mountains.
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