When you pick tires, the size and speed rating get most of the attention. But the load rating matters just as much, especially if you carry heavy loads, tow, or drive a truck or SUV. The two main ways to rate a tire’s load capacity are the load index and the load range. They sound similar but work differently. Here is what each one means and how to use them.
What Is a Tire Load Index?
The load index is a number on the sidewall that corresponds to a maximum weight a single tire can carry when properly inflated. It appears right after the size and before the speed rating. For example, a tire labeled 225/60R16 98H has a load index of 98.
That number is not the direct weight in pounds. It is a code. You look up the number in a load index chart to find the actual weight capacity. A load index of 98, for instance, equals 1,653 pounds at the tire’s maximum pressure. Lower numbers mean less capacity, higher numbers mean more.
- Common passenger car load indexes range from 75 to 100, roughly 850 to 1,650 pounds per tire.
- Light truck tires often use load indexes above 100 to handle heavier loads.
- The chart is standardized across all tire brands, so the number always means the same thing.
What Is a Tire Load Range?
Load range, sometimes called load rating or ply rating, is a letter that tells you how strong the tire’s internal construction is. It relates to the tire’s ability to withstand pressure and heavy loads without failing. Older tires used ply ratings like 4-ply or 6-ply, which referred to the number of rubber-coated fabric layers. Modern tires use letters instead.
Common load range letters include B, C, D, E, and F. Each one has a maximum air pressure that the tire can handle. A load range C tire is built for heavier duty than a B, and E is stronger than C. The letter is usually stamped near the size or in the tire’s service description.
- Load range B: typically used on half-ton trucks and full-size SUVs.
- Load range C: often on three-quarter-ton trucks and trailers.
- Load range E: common on one-ton trucks and heavy-duty work vehicles.
How They Work Together
The load index and load range are not separate choices. They complement each other. The load index gives you the exact weight limit at a given pressure, while the load range tells you how much air pressure the tire can safely hold. A tire with a high load range can carry more air, which often allows a higher load index. Together they define how much weight the tire can support and at what inflation level.
For instance, two tires might have the same size but different load ranges. The one with the higher load range can be inflated to a higher pressure, which increases its load capacity. That is why you should never exceed the maximum pressure molded on the sidewall. The load range is your clue about the tire’s structural limit.
Why It Matters for Your Vehicle
Using a tire with too low a load index or load range is dangerous. If you overload the tire, it can overheat, cause a blowout, or accelerate tread wear. Even if you do not usually carry heavy loads, an underrated tire can fail when you least expect it, especially during hot weather or long highway trips.
Conversely, using a tire with a much higher load range than necessary can make the ride stiff and harsh. It may also change the way your vehicle handles because the sidewalls are stiffer. Stick to the load rating recommended by your vehicle manufacturer, which is printed on the driver’s door jamb sticker or in the owner’s manual.
How to Find the Right Load Rating for Your Car
First, check the tire information placard on your driver’s door pillar. It lists the original tire size, load index, and sometimes the load range. That is your safest starting point. If you want to switch to a different tire size, use a professional tire size calculator that includes load capacity checks.
You can also look at the owner’s manual for towing and payload specifications. If you plan to tow a heavy trailer or haul a full load in the bed, choose a tire with a load index that covers at least the maximum weight per axle. Talk to a tire dealer about your specific vehicle and usage before buying.
Common Mistakes to Avoid
One common mistake is assuming that a higher load index is always better. That is not true. A tire with too high a load index may not transfer the vehicle’s weight properly, leading to a rough ride and uneven wear. Another mistake is relying only on the load range letter and ignoring the load index number. Both matter.
Another error is mixing tires with different load ratings. If you replace only one tire, get an exact match to the other side. If you replace two, put the new pair on the rear axle for better stability. Never combine a load range C tire with a load range E tire on the same axle.
Finally, remember that load ratings are tied to proper inflation. A tire that is underinflated will not reach its rated capacity. Check your tire pressure at least once a month and before any long trip.
Frequently Asked Questions
What is the difference between tire load index and load range?
The load index is a number that indicates the maximum weight a tire can carry when properly inflated. The load range is a letter that indicates the tire's structural strength and maximum air pressure. Both affect the tire's load capacity, but they measure different aspects of the tire's design.
Can I use a tire with a higher load index than my vehicle requires?
Yes, as long as the tire fits your wheel and doesn't interfere with brakes or suspension. A higher load index means a higher weight capacity, which can be beneficial if you carry heavy loads. However, it may result in a firmer ride and could change handling characteristics.
Where can I find the recommended load index for my car?
Look at the tire pressure and load placard on the driver's side door jamb, the glovebox door, or your owner's manual. It will list the original tire size, load index, and sometimes the load range. Always follow these recommendations for safety.
