A load index of 115 means your tire can safely carry 1,215 pounds when properly inflated

The load index is a number on your tire's sidewall that tells you the maximum weight one tire can support. A load index of 115 corresponds to 1,215 pounds per tire. This is the weight limit when the tire is inflated to the pressure listed on your driver's door jamb or fuel door — not the maximum pressure printed on the tire itself.

Load index matters because every vehicle has a total weight capacity spread across all four tires. If you buy tires with too low a load index, you risk tire failure, poor handling, and brake problems. If you buy tires with a higher load index than your vehicle needs, you are straightforward paying for capacity you will not use — though this does not harm your vehicle.

The load index is always paired with a speed rating (a letter like H, V, or W). Together they appear on the tire sidewall as something like "115H" or "115V". You need both numbers to match your vehicle's requirements.

Key Takeaways

  • A load index of 115 means one tire can safely hold 1,215 pounds at the vehicle manufacturer's recommended pressure.
  • Your vehicle's door jamb label lists the load index your tires must meet or exceed — this is the number to match when buying replacements.
  • Load index is separate from speed rating; a tire marked 115H has both a load index (115) and a speed rating (H).
  • Buying tires with a higher load index than required is safe but unnecessary; buying tires with a lower load index can damage your vehicle.

How load index connects to your vehicle's weight

Your vehicle has a Gross Vehicle Weight Rating (GVWR), which is the maximum total weight it can safely carry — passengers, cargo, fuel, and all. This weight is divided equally among your four tires (or unevenly if your vehicle is designed that way, which is rare). To find your vehicle's required load index, divide the GVWR by four, then find the load index number that matches or exceeds that weight.

For example, if your GVWR is 4,860 pounds, each tire needs to support at least 1,215 pounds. A load index of 115 (1,215 pounds) would be the minimum. A load index of 116 (1,235 pounds) would also work and give you a small safety margin.

Your vehicle's door jamb label already does this math for you. It lists the tire size and load index your manufacturer recommends. You should never buy a tire with a load index lower than what appears on that label.

Where to find the load index on your tire

The load index appears on the sidewall of every tire, printed as part of the tire size code. A typical sidewall marking looks like this: 225/65R17 115H. Breaking this down: 225 is the tire width in millimeters, 65 is the aspect ratio, R means radial construction, 17 is the wheel diameter in inches, 115 is the load index, and H is the speed rating.

You can also find your vehicle's required load index on a label inside the driver's door jamb, on the fuel door, or in your owner's manual. This label shows the recommended tire size and load index for your specific vehicle. When you replace your tires, match this label exactly, or choose a tire with a higher load index if your preferred size comes that way.

Load index versus speed rating

Load index and speed rating are two separate measurements that always appear together on a tire. The load index (115) tells you weight capacity. The speed rating (H, V, W, Y) tells you the maximum speed the tire can sustain safely. A tire rated 115H can carry 1,215 pounds and is safe up to 130 mph. A tire rated 115V can carry the same weight but is safe up to 149 mph.

Your vehicle's door jamb label specifies both numbers. You must meet or exceed the load index, and you should match the speed rating unless you have a specific reason not to. Buying a tire with a lower speed rating than recommended can affect handling and braking, especially in emergency situations. Buying a higher speed rating is safe but costs more.

What happens if you use the wrong load index

Using a tire with a load index lower than your vehicle requires creates real safety risks. The tire will flex more than it should under your vehicle's weight, generating excess heat. This heat can cause the tire to fail suddenly, especially on long drives or in hot weather. Underrated tires also affect your vehicle's handling and braking distance because the suspension and brakes are designed to work with tires of a specific stiffness.

Using a tire with a load index higher than required is safe. The tire will straightforward be stiffer and more durable than necessary. You may notice a slightly firmer ride, but this does not damage your vehicle. Many people choose a higher load index for added durability, especially if they frequently carry heavy loads or tow.

Load index for trucks and vehicles that carry heavy loads

If you own a truck, SUV, or vehicle that regularly carries passengers and cargo, pay close attention to your GVWR and the load index it requires. Some trucks have a GVWR high enough that they need a load index of 120 or higher. If you tow a trailer, the tongue weight of the trailer counts toward your vehicle's total weight, so your tires must support that additional load.

If you are unsure whether your current tires have the right load index for your actual driving habits, check your door jamb label and compare it to the sidewall of your current tires. If they do not match, your next tire purchase should bring them into alignment. Your vehicle's manufacturer chose that load index for a reason.

Frequently Asked Questions

Can I use a tire with a load index higher than my vehicle requires?

Yes. A higher load index means the tire can support more weight, which is safe for your vehicle. You may pay more for that extra capacity, but it will not harm your vehicle or its performance.

What is the difference between load index and load range?

Load index is a number (like 115) that corresponds to a specific weight in pounds. Load range is a letter (A, B, C, D, E) used mainly on truck and trailer tires to indicate ply rating and load capacity. Most passenger car tires use load index; most truck tires use load range. Check your door jamb label to see which your vehicle requires.

If I upgrade to a larger tire size, will the load index change?

Usually yes. A larger tire size often has a different load index. When you change tire sizes, you must verify that the new size meets or exceeds your vehicle's load index requirement. Your tire shop can help you find a larger size that maintains the correct load capacity.

Does load index affect fuel economy?

Slightly. A tire with a higher load index is typically stiffer and may have slightly more rolling resistance, which can reduce fuel economy by a small amount. The difference is usually not noticeable unless you are comparing very different load indexes.