 
Speed Ratings
Many of today's automobiles come equipped with speed rated Original Equipment tires. Speed rating passenger tires originated in Europe, where highway speeds can exceed 100 mph(160kph). The speed rating indicates the maximum speed a properly inflated tire will withstand for a determined time. Testing for speed rating certification is conducted in a laboratory setting.
NOTE: The speed rating is void if the tires are worn out, damaged, repaired, retreaded, or otherwise altered from their original condition. If tires are repaired, retreaded, or otherwise altered, they should not be operated at higher than normal highway speeds.
| SPEED SYMBOL |
SPEED MPH |
SPEED KPH |
| M |
81 |
130 |
| N |
87 |
140 |
| P |
93 |
150 |
| Q |
99 |
160 |
| R |
106 |
170 |
| S |
112 |
180 |
| T |
118 |
190 |
| U |
124 |
200 |
| H |
130 |
210 |
| V*(VR) |
149 |
240 |
| W**(ZR) |
168 |
270 |
| Y**(ZR) |
186 |
300 |
*Current tire speed rating markings include the use of the service description to identify the tire's speed capability (P215/65R15 95V -maximum speed 149 mph).
**Any tire with a speed capability above 149 mph(240(kph) can, at the tire manufacturer's option, include a "ZR" in the size designation (P275/40ZR17). If a service description IS NOT included with the size description, the tire manufacturer must be consulted for the maximum speed capability(P275/40ZR17--speed capability is >149mph). If a service description IS included with the size description, the speed capability is limited by the speed symbol in the service description (P275/40ZR17 93W = maximum speed 168 mph(270kph).)
Speed Rating Characteristics
Tires have always had the ability to change an automobile's driving characteristics. Technology has given the tire an important role as a component of the automobile suspension.
The speed rating of the tire is an indicator of the tire's performance capability. Improving the tire's performance capability will normally benefit an automobile's performance. Conversely, decreasing the tire's speed rating generally lowers the tire's ability to contribute to the automobile's performance.
Changing from the O.E. tire speed rating to another performance level tire will probably change handling in areas such as:
| 1. Steering Response |
4. Cornering |
| 2. Braking |
5. Evasion/Recovery |
| 3. Traction |
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