Load Index/Speed Rating
The speed rating is the maximum service speed of a passenger car tire. Light truck (LT type) tires may not be speed rated. Here is a list of rating indicators and their mile-per-hour equivalents. This rating system applies to all tire makers.
|V||Above 130 mph (without service description)|
|V||149 mph (with service description)|
|Z||Above 149 mph|
When "ZR" appears in the size designation with the service description, the maximum speed is as indicated by the service description.
|Tire Designation||Max. Speed|
|P275/40ZR17 93W||270 km/h (168 mph) |
|P275/40ZR17 93Y||300 km/h (186 mph) |
For tires having a maximum speed capability above 240 km/h (149 mph), a "ZR" may appear in the size designation. For tires having a maximum speed capability above 300 km/h (186 mph), a "ZR" must appear in the size designation. Consult the tire manufacturer for maximum speed when there is no service description.
|Speed Symbol||Speed (km/h)||Speed (mph)|
|V*||Above 110||Above 130|
|Z**||Above 240||Above 149|
* For unlimited V Tires without Service Description, the speed category is over 210 km/h (130 mph)
** For unlimited Z Tires without Service Description, the speed category is over 240 km/h (149 mph)
Do speed-rated tires cost more than other radials?
Tires are highly engineered products designed to support the weight (load) of the vehicle, its passengers, and its contents. In addition the tires have the responsibility to make the car accelerate, decelerate (or stop), and corner under a wide variety of weather and road conditions. They must do this under normal conditions and in evasive maneuvers. We as drivers and passengers also ask the tires to carry us in quiet comfort and security and provide a reasonable tread life.
As we increase the tire's performance capability, moving up through the speed ratings from non-rated passenger tires to the highest of the Z-Rated tires, the prices of tires usually follow suit. However, one of the best values today is a tire designed, engineered, and produced for your vehicle and the way you drive. While the price for the most of life's necessities have increased over the years, tire prices have continued to be quite reasonable.
My car came equipped with V-rated tires. Can I switch to a lower rating?
We do not recommend downgrading the speed ratings of tires for your vehicle. Speed Ratings are a durability standard defining a tire's ability to withstand, or control, heat and growth. The components engineered to do this add performance characteristics and benefits to the tire commiserate with each speed rating level. This is not to say that all tires of equal speed rating are equal in all respects. However, within a tire manufacturer's line of products an H-Rated tire usually handles, or "performs" better than an S-Rated tire, and a Z-Rated tire usually handles better (has crisper steering response and overall greater cornering grip) than an H-Rated tire. Each tire line (or model) within a speed rating can be designed and engineered to provide specific performance characteristics depending upon the typical user's wants, needs, and desires.
You should try to match the tire's handling personality to that of your car. Your car is probably one of the most expensive purchases you have made. Ensure that you maintain the performance characteristics you like about the vehicle by selecting a tire with equal or greater performance capabilities.