The load index is a number on your tire that tells you the maximum weight that single tire can safely carry

Every tire has a load index printed on its sidewall — a two or three-digit number that appears right after the tire's width and aspect ratio. This number corresponds to a specific weight capacity measured in pounds or kilograms. For example, a load index of 95 means that tire can safely support 1,521 pounds; a load index of 100 means 1,764 pounds. The higher the number, the more weight the tire can handle.

Your vehicle's owner manual and the placard on the driver's door jamb list the load index your tires must meet. You cannot use a tire with a lower load index than what your vehicle requires, because the tire will not safely support your car's weight plus passengers and cargo. Using an under-rated tire risks blowouts, uneven wear, and loss of control. Using a tire with a higher load index than required is safe — it straightforward means you have extra capacity you do not need.

Key Takeaways

  • The load index is a number on the tire sidewall that corresponds to the maximum weight one tire can carry, and you can find the required load index in your vehicle's owner manual or on the driver's door jamb.
  • You must never use a tire with a load index lower than your vehicle requires, because it will not safely support your vehicle's weight.
  • Load index increases by roughly 40 pounds for each whole number step, so a tire rated 95 carries about 40 pounds less than one rated 96.
  • When replacing tires, match or exceed the load index of your original tires unless your vehicle manufacturer approves a different rating.

How to find your vehicle's required load index

Open your vehicle's owner manual and search the tire or wheel section. The manual will list the tire size and load index together — for example, "P225/65R17 102H" where 102 is the load index. If you do not have the manual, look at the driver's door jamb (the vertical surface you see when you open the door). A white or yellow placard there lists the tire size and load index required for your vehicle.

You can also look at your current tires. The sidewall of each tire displays its size and load index. Write down the load index from one of your existing tires — this is what you need to match or exceed when you buy replacements. If your tires are worn and you are unsure of the original rating, the door jamb placard is your most reliable source.

Understanding the load index number scale

Load index numbers run from 0 to 150, though most passenger vehicles use indexes between 75 and 110. Each whole number represents roughly a 40-pound increase in capacity. A tire with a load index of 95 can carry about 1,521 pounds; one with a load index of 96 can carry about 1,565 pounds. This means a single-step difference sounds small but adds up across all four tires.

The relationship is not perfectly linear at the extreme ends of the scale, but for the range you will encounter on passenger cars and light trucks, you can estimate that each number up equals roughly 40 more pounds per tire. This matters when you are comparing tire options. If your vehicle requires a load index of 100 and you find a tire rated 98, that tire is under-rated by about 80 pounds total capacity per tire — a gap you should not accept.

What happens if you use the wrong load index

Using a tire with a load index lower than required puts stress on the tire that it was not designed to handle. The tire flexes more than it should, generates excess heat, and wears unevenly. Over time or under heavy load — such as highway driving with a full car or towing — an under-rated tire can fail suddenly. A blowout at highway speed is dangerous and can cause loss of control.

Using a tire with a load index higher than required is not a problem. The tire straightforward has capacity you do not use. Many people upgrade to a higher load index when replacing tires, especially if they plan to carry heavier loads or tow a trailer. This is safe as long as the tire still matches your vehicle's other specifications, such as size and speed rating.

Load index versus speed rating

The load index is only one part of a tire's rating. Every tire also has a speed rating — a letter that appears at the end of the tire size, such as H, V, or W. The speed rating tells you the maximum speed the tire can sustain safely. A tire marked "102H" has a load index of 102 and a speed rating of H (130 mph maximum sustained speed).

When you replace your tires, you must match or exceed both the load index and the speed rating of your original tires. Your vehicle manual or door jamb placard will list both. If your original tires are rated 102H, your replacement tires should be at least 102H — not 102G or 100H. Matching both ratings ensures your new tires are designed for the same demands as the originals.

Checking load index when buying replacement tires

Before you purchase replacement tires, write down the load index and speed rating from your door jamb placard or owner manual. When you shop online or in a tire store, filter by your vehicle's year, make, and model — this usually shows you only tires that meet the factory specifications. If you are browsing by tire size alone, check the sidewall information on every option to confirm the load index matches or exceeds what you need.

Some tire retailers will not sell you a tire with a lower load index than required, because they know it is unsafe. Others may allow it if you sign a waiver. Do not accept an under-rated tire even if it costs less. The small savings are not worth the risk of a blowout or tire failure. If a tire in your preferred size and brand is not available in the load index you need, choose a different tire or wait for stock to arrive.

Load index for trailers and specialty vehicles

If you tow a trailer, your vehicle manual will specify the load index required for towing. Towing puts extra stress on your tires because the total weight — vehicle plus trailer — is higher than normal driving. Your tires must be rated for this combined weight. Check your manual for the towing-specific tire requirements, which may be higher than the standard load index for normal driving.

Specialty vehicles such as trucks used for hauling or vans used for commercial purposes may have different load index requirements than the same model used for personal driving. Always consult the manual or door jamb placard for your specific vehicle configuration. If you are unsure whether your vehicle is rated for a particular use, contact the manufacturer or a tire professional before buying tires.

Frequently Asked Questions

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

Yes, using a tire with a higher load index is safe. The tire straightforward has more capacity than your vehicle needs. Many people choose higher load index tires for extra durability or if they plan to carry heavier loads occasionally. Just make sure the tire still matches your vehicle's other requirements, such as size and speed rating.

What does the letter at the end of the tire size mean?

That letter is the speed rating, which tells you the maximum speed the tire can sustain safely. Common ratings are H (130 mph), V (149 mph), and W (168 mph). You should match or exceed your vehicle's original speed rating when buying replacement tires, just as you do with load index.

Where do I find the load index if my tires are very worn?

Check your vehicle's owner manual or the placard on the driver's door jamb. Both list the tire size and load index your vehicle requires. You do not need to read it from the tire itself — the manufacturer's specifications are your reliable source, even if your current tires are nearly bald.

Does load index change if I switch to a different tire size?

Yes. Different tire sizes have different load indexes. If you change your tire size — for example, from 225/65R17 to 235/65R17 — the load index will likely change as well. You must verify that the new tire size and load index meet your vehicle manufacturer's requirements. Do not assume a larger tire automatically has a higher load index.

What happens if I accidentally buy tires with too low a load index?

Contact the tire retailer when ready and explain the situation. Most reputable shops will not install under-rated tires and will help you exchange them for the correct rating. If tires have already been installed, have them removed and replaced. The cost of an exchange is far less than the risk of a blowout or tire failure.