Sumitomo Tire 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 & their mile-per-hour equivalents. This rating system applies to all tire makers.

 
Rating Maximum Speed
Q 99 mph
S 112 mph
T 118 mph
U 124 mph
H 130 mph
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.

Examples:

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
V 240 149
Z** Above 240 Above 149
W 270 168
Y 300 186

* 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, & its contents. In addition the tires have the responsibility to make the car accelerate, decelerate (or stop), & corner under a wide variety of weather & road conditions. They must do this under normal conditions & in evasive maneuvers. We as drivers & passengers also ask the tires to carry us in quiet comfort & security & 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, & produced for your vehicle & 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 & growth. The components engineered to do this add performance characteristics & 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, & a Z-Rated tire usually handles better (has crisper steering response & overall greater cornering grip) than an H-Rated tire. Each tire line (or model) within a speed rating can be designed & engineered to provide specific performance characteristics depending upon the typical user's wants, needs, & 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.

Load Index & Load in lbs.
One pound is equal to 0.4536 kg.
The load index is an assigned number that corresponds with the load-carrying capacity of a tire. Most passenger car tire load indexes range from 75 to 100 but a few carry more.

 
Load Index Load (lbs) Load Index Load (lbs)
65 639 85 1135
66 661 86 1168
67 677 87 1202
68 694 88 1235
69 716 89 1279
70 739 90 1323
71 761 91 1356
72 783 92 1389
73 805 93 1433
74 827 94 1477
75 853 95 1521
76 882 96 1565
77 908 97 1609
78 937 98 1653
79 963 99 1709
80 992 100 1764
81 1019 101 1819
82 1047 102 1874
83 1074 103 1929
84 1102 104 1984


How is the tire's speed capability achieved?
As the speed of a tire increases, its components tend to grow or deform. This deformation leads to heat generation. This is a normal effect of the deformation of the tire's components due to centrifugal force. The faster the tire spins, the greater its tendency to deform. And the more it deforms, the more heat is generated.

But for tires driven at high speeds, controlling heat levels is critical. Engineers must find ways to control tire growth so that heat levels are confined to acceptable tolerances.

To overcome this problem, speed-rated tires are designed with advanced belt configurations engineered to resist & control deformation. This allows the tire to be driven at higher speeds without excessive heat buildup.


How does the speed rating relate to handling?
There is no requirement or standard that stipulates that the handling of a tire improves as the speed ratings move up the scale. However, as stipulated earlier, the components used to control the growth or deformation of the tire tend to also contribute to more control of the tire's footprint. As we control the tire for durability moving up the scale, we have the components readily available to control the handling & performance expected of the higher speed ratings.

Sumitomo Tire does not advocate or recommend the use of any of its products in excess of the legal speed limit.