What does 91w after the tire model number mean?
2 Answers
The maximum speed required for the tire. Specifically, 91 refers to the load-bearing capacity of the tire being 615 kilograms, and w indicates the maximum operating speed of the tire is 270 km/h. Depending on the maximum speed they can bear, tires can be classified into different speed grades from A to Z, with grade A further divided into eight subgrades from A1 to A8. Generally, the further back the letter representing the tire's speed grade is in the alphabet, the better the tire's performance.
The numbers and letters after the tire model, like 91w, are quite important to me. The 91 stands for the load index, meaning each tire can bear a maximum weight of 615 kilograms under specific testing conditions. The w is the speed rating symbol, indicating the tire's maximum safe speed is 270 kilometers per hour. These markings are set by international standards and can be found on the sidewall of every tire. In practical use, if you buy mismatched tires—such as those with a lower load index or speed rating—it can lead to faster wear or even blowouts during high-speed driving or when fully loaded. I once researched my SUV and found that the factory-installed tires were 91w, ensuring good performance for hill climbing and safe overtaking. So, when choosing tires, always refer to your vehicle's manual and don't make random changes. Regularly checking your tire condition is also a good habit for maintaining safety.
