When shopping for tires, you may have noticed the 120s designation and wondered what it meant. 120s refer to the tire's load index and speed rating. The load index is a numerical code that corresponds to the maximum weight that the tire can support when properly inflated. The speed rating tells you the maximum speed at which the tire can be driven safely.
The combination of these two numbers provides important information about a tire's capabilities. For example, a tire with a load index of 120 and a speed rating of S can safely carry 2,271 lbs at 112 mph. Knowing this information can help you choose the right tires for your vehicle and driving needs.