Understanding Tire Speed Ratings

Introduction

When looking for new tires, tire speed ratings play a crucial role. However, many drivers are unaware of these ratings. Driving at a speed higher than what the tire is rated for can be a safety hazard. Not only is it dangerous for yourself, but also for others on the road. To ensure safety, it is recommended to understand the tire speed rating and how it fits your driving needs.

In this guide, we will unfold the concept of tire speed rating and high-speed tire safety in detail, including the rating chart, the importance of speed rating, and where one can find it written on the tire. Let’s dive into tire speed rating explanation!

Understanding Tire Speed Rating

A tire speed rating is the optimal speed value at which a vehicle can be driven safely, for a sustained amount of time, while keeping factors like temperature, weather, inflation pressure, and tire life in ideal conditions.

In simpler terms, a tire speed rating is the maximum speed the tire can handle. For truck mud tires, which are designed for off-road conditions, having an appropriate speed rating is crucial to ensure they perform well under rugged terrain. A higher speed rating not only characterizes the durability of the tires but also enhances control and handling, especially in challenging environments.

Why was the Speed Rating System Developed?

The speed rating system was developed in Europe to ensure the safety and performance of the tires at a higher speed. The speed rating was first developed with the letter V at a rating of 210 Km/hr.

However, with technological advancements, the top speed of vehicles was increased, and the speed rating system was extended with the new and higher top speed limits. The “Limited V” category was introduced with a top speed limit of 250 Km/hr and finally up to the letter Z.

How and Where to Find Tire Speed Rating?

Wondering where to find tire speed ratings for a vehicle? There are multiple ways to explore and find out the right speed rating of tires for your vehicle. First of all, the manufacturer’s manual should be your priority when checking all the details related to the tire speed rating. Moreover, you can also find the recommended tire speed rating on the side door sticker, gas tank hatch, or inside the glove box.

However, sometimes you can also find the speed rating on the tire itself! The tire’s sidewall is full of useful information regarding the manufacturer, tire width, aspect ratio, load index, and speed rating. The speed rating is quite easy to find as it is the last alphabet in the character sequence of the tire size code. For example, P210/60R15 72V is the character sequence on the sidewall of a tire. In this sequence, “V” is the speed rating of the tire, which corresponds to a top speed of 240 Km/hr.

How Are Tire Speed Ratings Determined?

The tire speed rating system utilizes multiple parameters such as heat, tire quality, and speed on a testing machine to meet the standards of the Economic Commission for Europe (ECE) and the Society of Automotive Engineers (SAE). The basic difference between the two testing standards is the temperature.

When tested for ECE, a vehicle’s tire is rotated with a pressure drum at a speed of 40 Km/Hr. and 77º F. In the case of SAE testing, the temperature will increase up to 100º F.

However, it must be noted that the tire speed rating is being tested under a controlled environment and, hence, should not be idealized as an exact maximum speed value. This means that the actual maximum speed value for your tire might be lesser than the speed rating and is greatly affected by tire inflation, temperature, quality, wear & tear, and more. Additionally, be informed that the tire speed ratings are not applicable to damaged or worn-out tires.

Tire Speed Rating System — Tire Speed Ratings 101

The tire speed rating system utilized these days starts from the alphabet “A” and ends with the alphabet “Z.” The First alphabet, “A,” being the lowest speed rating, moves towards a higher value until “Z.” Each alphabet corresponds to a specific speed limit.

Moreover, some anomalies in this system must be taken care of while understanding the tire speed rating system. For example, the alphabet “H” is not in the right place and appears between “U” and “V.” Some alphabets, such as “I,” “O,” and “X,” are not part of this rating system.

Additionally, the lowest speed rating corresponds to the alphabet “A” and hence is categorized into different sub-parts such as A1, A2, and A3. Some of the speed rating charts mention “Z” as the highest speed rating, but some have a list confined to “(Y)”— both have the same speed value, i.e., above 300 Km/hr.

Tire Speed Rating Chart

Here’s a complete chart of tire speed ratings that are accepted worldwide. However, as mentioned before, the highest speed rating can be denoted with the alphabet “Z” or “(Y).”

SPEED SYMBOLS
Symbol Speed	Speed (km/h)	Speed (mph)
A1	5	3
A2	10	6
A3	15	9
A4	20	12
A5	25	16
A6	30	19
A8	40	25
B	50	31
C	60	37
D	65	40
E	70	43
F	80	50
G	90	56
J	100	62
K	110	68
L	120	75
M	130	81
N	140	87
P	150	94
Q	160	100
R	170	106
S	180	112
T	190	118
U	200	124
H	210	130
V	240	149
W	270	168
Y	300	186
(Y) / Z	Above 300	Above 186

Conclusion

Understanding tire speed rating and carefully following it ensures both high-speed tire safety and performance. However, there are some important things to keep in mind even after comprehending the speed ratings for your tires. You must remember that the mentioned speed rating is not the actual speed limit you should drive on as the actual speed capacity can be way less than the written rating due to climate or tire conditions.