A tire’s sidewall contains more information than just the brand and model—it also holds crucial details about performance specifications. Among these is the tire load index, a key figure that indicates how much weight a tire can safely support when properly inflated. Understanding this rating is essential for ensuring your vehicle operates safely, whether you’re hauling cargo, towing a trailer, or simply carrying passengers.
What Is a Tire Load Index?
The tire load index is a numerical value representing the maximum weight a tire can support at full inflation. While the number itself doesn’t indicate the weight directly, it corresponds to a specific load capacity listed in a tire load rating chart. The higher the number, the greater the tire’s carrying capacity.
For instance, a load index of 94 means the tire can support 1,477 pounds. When multiplied by four (since a car typically has four tires), the total carrying capacity would be 5,908 pounds. This should always exceed the vehicle’s gross vehicle weight rating (GVWR), which includes both the car’s curb weight and the maximum additional load it can handle.
Where to Find the Load Index on a Tire
The tire load index is typically found at the end of the alphanumeric string on the tire’s sidewall, just before the speed rating letter. For example, in a tire labeled 235/45R18 94V, the 94 represents the load index, while the V indicates the speed rating. If you’re unsure of the correct load index for your vehicle, you can check the owner’s manual or the tire data plaque located on the driver’s side door jamb.
Why the Load Index Matters
Using tires with an inadequate load index can compromise safety. If a tire isn’t rated to handle the weight of the vehicle and any additional load—such as passengers, luggage, or a trailer—it could wear out faster, impact performance, or even suffer a catastrophic blowout. A tire failure at high speeds can lead to a loss of control, increasing the risk of accidents.
For those who tow trailers or carry heavy loads, selecting tires with an appropriate load rating is even more crucial. A tire’s load capacity is measured at maximum air pressure, so underinflation can further reduce its ability to support weight, leading to premature wear and potential tire failure.
Load Index Ratings and Tire Types
Most passenger car and light truck tires fall within a load index range of 70 to 124, with 117 being a common rating for standard vehicles. However, tire classifications can vary:
- Passenger vehicle tires (P-rated) have a single load index value.
- Light truck (LT) and trailer (ST) tires may feature dual load indexes (e.g., 104/101S) to account for their use on single or dual-wheel setups. For instance, a Silverado 3500HD dually would use the lower number for its rear wheels since they operate in pairs.
Tire Load Index Chart
Here’s a reference chart displaying common tire load indexes and their corresponding weight capacities:
| Load Index | Load Capacity (lbs) |
|---|---|
| 70 | 739 lbs |
| 75 | 852 lbs |
| 80 | 992 lbs |
| 85 | 1,135 lbs |
| 90 | 1,323 lbs |
| 94 | 1,477 lbs |
| 98 | 1,653 lbs |
| 100 | 1,764 lbs |
| 105 | 2,039 lbs |
| 110 | 2,337 lbs |
| 115 | 2,679 lbs |
| 120 | 3,086 lbs |
| 124 | 3,527 lbs |
This chart provides an easy way to determine the maximum weight each tire can handle based on its load index. If you’re frequently hauling cargo or towing, choosing tires with a higher load index than the factory recommendation may offer better durability and safety.
Choosing the Right Tires
When replacing tires, always select ones that match or exceed the factory-recommended load index. Using tires with a lower load rating than originally specified can lead to increased wear, handling issues, and safety risks. If your vehicle frequently carries additional weight—such as towing a camper or transporting equipment—you may benefit from tires with a higher load index than the stock recommendation.
To ensure you’re getting the correct tires, refer to your vehicle’s manual, door jamb sticker, or trusted online resources before making a purchase. By doing so, you’ll help maintain performance, safety, and longevity for both your tires and your vehicle.
Tire Load Index Explained – Video
For a visual breakdown of how the tire load index works, check out this short video:
