Tire Speed Ratings and Load Ratings

Tire speed ratings should be considered alongside load rangings to determine safety and efficiency. Why? Because a tire's maximum speed is determined under optimal conditions, this assumes that the load capacity has not been exceeded during normal operation. For the lower end of the tire speed rating, it is possible for an ordinary driver with a lead foot to approach the maximum that particular tire is rated for. If you are nearing the tire speed rating max, with a load approaching the maximum for that tire, the safety margin gets smaller and smaller. The closer you are to the max load, speed, or both, the closer you get to a potential tire failure. If you are hauling a heavy load and driving highway miles, make certain you know the limitations of your tires in both departments. Check the sidewall of your tires for all this pertinent information, especially on a 'new-to-you' vehicle.

Tires that have a higher speed rating are useful for cars that travel long distance or on fluctuating road conditions. If you're a heavy-duty driver, decrease your chances of tire failure from various road conditions with new tires that have a higher tire speed rating.