Just as you should not buy tires with lesser speed ratings than required by the car maker, you shouldn't purchase tires not equipped to carry their designated load.
Many consumers don't realize that the tire load rating is one of the most important attributes when considering the purchase of your next set of tires . . . since excessive loads can damage your tires, effectively shortening their lifespans.
When you count the weight of the vehicle itself, the occupants inside, and the cargo loaded in (or on) the vehicle, it all begins to add up. The tire load rating tells car owners the amount of weight each tire can safely carry when properly inflated.
Automotive and tire manufacturers take into consideration the overall weight of the vehicle when loaded with both passengers and cargo. With these factors in mind, the tire should ideally be able to support the vehicle's weight when fully loaded.
So how can you tell the load index rating of a particular tire? It's right there on the tire sidewall. For instance, a P195/60R15 87S tire has a load index of 87, which identifies the tire's ability to carry approximately 1,201 pounds. The higher the tire's load index number, the greater its load carrying capacity. Most tires have a load index rating of 70 - 110.
Fortunately, carmakers specify the tire load index for your particular vehicle. You should be able to find your manufacturer’s OE specs in your manual or on your door placard, where you’ll see the recommended tire size, load rating and maximum tire pressure. But if you are interested, click here to view a load index table.
The bottom line is . . . Never install a tire with a load index less than what is recommended by the manufacturer!