What is load index and why is it important? Does load index vary based on application? What’s the best way to determine the right load index for your customers’ tires?
“The load index is a number found at the end of the size on a tire,” says Dave Paulk, manager, field technical services, BKT USA Inc. “There is a chart (load index chart) that shows the value of that number in load carrying capacity for the tire.”
For Example: Size 480/80R50 159 A8/B
“In this example, the load index is 159. The load index is the load carrying capacity of the tire at maximum air pressure and maximum speed. In this case, the load index equals 9,640 lbs. per tire of weight carrying capacity.
“Load indexes are numerical values used in radials in place of ply ratings and star ratings,” says Paulk. “Since air pressure carries weight, the higher the load index, the more air pressure the tire will use. Load indexes are important to make sure the tire will carry the required load at the required speed without failing.
“Load indexes can vary based on the application. The heavier the tractor or the implement, the heavier the load index needs to be. On tractors, if a user is running a heavy front end or using the three-point hitch, they may need to go to a heavier load index tire to carry the weight or consider running duals. This is also a good application for IF/VF tires with heavier load indexes.”
According to Paulk, the best way to determine the correct load index is by knowing how much weight the tire needs to carry. “With this information, it is possible to choose the load index that will optimize the use of the tire and minimize failures,” he says.
“We suggest looking at worst case scenarios when choosing the right load index. How much weight does the tire need to carry at the maximum speed it will run? This solves many problems.”
