Interpret ratings on Hankook tires by going to the company's tire safety Web page and checking the chart for the maximum recommended speed for tires in the different categories. The speed symbol rating is the single-letter designation on the tire following the two-digit load index number.
Hankook's speed symbol designations are verified to be in compliance with the Economic Council for Europe: Procedure Load/Speed Performance test for tires. Each letter category on the Hankook Web page chart represents a different maximum speed. For instance, tires with the letter "H" have a maximum speed of 130 mph. Speed ratings are also given in kilometers per hour.
Speed ratings do not apply to tires that are damaged or altered in any way, and they assume that the tires are not over- or underinflated. In addition, the speed rating no longer applies to a repaired tire because the manufacturer has no way of knowing whether the repair was done correctly. All manufacturers recommend driving under the legal speed limit, regardless of the maximum speed rating set for the tires. If each tire on a vehicle has a different speed rating, the maximum speed for the vehicle matches the one on the lowest speed-rated tire.