Modern passenger tires have a tire speed rating. This is a label that indicates the tire’s speed capability. It’s simply the speed at which a tire can travel before it stops performing as intended. The tire speed rating does not mean that the vehicle can be safely driven at the maximum speed it is capable of, especially in adverse weather conditions.
HOW TO FIND YOUR TIRE SPEED RATING
The manual will tell you what the recommended tire speed rating for your vehicle. It might be found in the driver’s side jamb, gas tank hatch or glove box door.
It’s easy to find the speed rating because it is usually the last item in a tire’s size sequence. In this example, the tire code is “P205/60R16/82S,” where S is the speed rating. Look at the sidewall to see the current tire size code. Is the tire’s speed rating in line with the manufacturer’s recommendations? It should!
Remember that the tire speed rating does not necessarily indicate a recommended speed for travel. Although the tire speed rating will almost always exceed the maximum highway speed limit, no tire manufacturer or vehicle manufacturer recommends driving faster than what is allowed by law.
DETERMINING TIRE SPEED RATING
Speed ratings are based on laboratory testing, which includes simulations of speeds and loads. A tire must be capable of maintaining a certain speed to receive any type of rating. The industry standards regulate the way a tire can maintain a certain speed during a test.
It is important to keep in mind that not all conditions can be replicated by the lab. Your tire’s speed rating is an indicator of its ability under controlled conditions (i.e. Fully inflated, vehicle running smoothly, and good weather conditions. The actual speed of your tires may be lower than the rated speed. This is due to factors like inflation, wear, vehicle condition (including alignment), driving conditions, and how long speed is maintained. Tires that have been altered, damaged, over-inflated, or repaired do not qualify for speed ratings.
TIRE SPEED RATING SYSTEM QUIRKS AND ANOMALIES
The letters A through Z are the speed rating system of today. Each letter corresponds with a speed. The speed increases alphabetically as the rating goes up. A tire rated L has a slower maximum sustained speed than a tire rated N.
The tire speed rating system has its flaws, however. The system’s European roots mean it can achieve unusually high mile per hour speeds. Another peculiarity is the absence of the letter H. It is not placed after “G”, but instead it falls between “U” and “V”, depending on the speed at which it corresponds.
The following are additional speed ratings “anomalies”.
There are no speed ratings for “I”, “O,” or “X”. Some speed rating charts also don’t include “P” rating.
The lowest speed rating tires are often listed with “A”, followed by a number, such as “A1, “A2, or “A3,” etc.
Some tires have “W” and “Y” speed ratings. For these types of tires, manufacturers may add “Z” to the size description (in tire code data between aspect ratios and diameter).
The unlimited “V” rating was the first speed rating system to be developed. This was applicable to tires with a maximum sustained speed of 149 mph (240 km/h) or greater. As more tire manufacturers produced tires capable of handling speeds exceeding 149 mph, but still hitting a maximum speed, “V” was reduced to 149 mph (instead of 149+mph), and the speed ratings for “W” as well as “Y” were added.
Some tire speed rating charts will also indicate the “Z” rating for any tire that is rated at more than 149 mph. Manufacturers may insert a “Z”, right after the aspect ratio, in the middle section of the tire size description. And if the tire’s speed rating is greater than 186 mph (300 km/h), the manufacturer will usually include a “Z,” within the size description. This is consistent with industry standards.
EXPLORE PERFORMANCE TIRES
COMMON TIRE SPEED RATINGS CHART
These speed ratings are the most common for vehicles of ordinary size. These speed ratings start at 118 mph (190 km/h), and then increase as you go.
Each rating corresponds with a speed and is indicated by a letter.
SPEED RATING T
You will find tires with speed rating T on minivans and family sedans that can reach a maximum speed exceeding 118 mph.
SPEED RATING H
The “H” speed rating is not located after “G”, but instead between “U” or “V.” It’s a speed rating that allows for a maximum speed of 130mph (210 km/h), and can be found on both sports sedans as well as coupes. The speed rating system used to be called “high performance” in earlier versions. This is why “H” still occupies a unique position on the speed rating spectrum.
SPEED RATING V
The highest possible tire speed rating, “V”, used to be a maximum of at least 149 mph (240 km/h). It is now 149 mph, but not higher.
SPEED RATING W
The speed rating wheel has a new addition: tires with speed rating W can reach a maximum sustained speed speed of 168 mph (270 km/h).
SPEED RATING Z
Different things can be meant by a “Z” rating. It can mean a high-performance tire designed for high-performance sports cars. However, it may appear in the middle information about a tire’s dimensions. It can indicate a maximum speed greater than 149 mph (240 km/h) or 186mph (300 km/h). It will vary depending on which tire it is referring to. For more information on Z-rated tires, contact the manufacturer. This speed rating is more common for owners of sports cars than those who own typical family sedans.
Choose the speed rating that corresponds with your vehicle manufacturer’s specifications and ensure all four tires have the exact same rating. Speed ratings are determined by laboratory testing under controlled conditions. These tests are intended to measure performance under controlled conditions. However, real-life driving may not be the same as those in laboratory tests.