Tire Load Ratings: Your Guide to Tire Load Index and Load Range

When it comes to choosing the right tires for your vehicle, there's more to consider than just the size and brand. Tire load ratings — denoted by the tire load index and load range — are critical factors that ensure your tires can safely carry the weight of your vehicle and its cargo. In this guide, we'll explore the tire load rating chart, decode the load index, and understand load range to help you make informed decisions.

Understanding Tire Load Index

The tire load index is a number found on your tire's sidewall that indicates the maximum weight a single tire can safely support when properly inflated. This number corresponds to a specific load capacity in pounds or kilograms. The higher the load index, the greater the weight the tire can bear.

You'll find the load index as part of the tire's service description — the numbers and letters that follow the tire size. For example, in 225/65R17 102H:

• 102 is the load index (1,874 lbs per tire)
• H is the speed rating (130 mph max)

Complete Tire Load Index Chart

Here's a comprehensive reference chart for common load index values:

Tire Load Range Explained

While load index tells you the exact weight capacity, load range (denoted by a letter) indicates the tire's construction strength and maximum inflation pressure. Load range replaced the older "ply rating" system.

Load Range Chart

What Do the Ply Ratings Mean?

Modern tires aren't literally constructed with that many plies of fabric. The ply rating is a strength equivalency — a Load Range E tire has the strength equivalent of a 10-ply tire, even though it may use fewer plies of stronger materials like steel and polyester.

SL vs. XL Ratings

For passenger tires, you'll also see:

• SL (Standard Load) — rated to 35 PSI max, suitable for standard passenger vehicles
• XL (Extra Load) — rated to 41 PSI max, provides higher load capacity for the same tire size

XL tires are common on heavier sedans, crossovers, and performance vehicles that need additional load capacity. Learn more in our XL tires explained guide.

How to Read Tire Load Ratings on the Sidewall

Every tire sidewall contains all the information you need. Here's how to decode it:

Example: P225/65R17 102H

• P — Passenger tire (LT = Light Truck)
• 225 — Section width in mm
• 65 — Aspect ratio (sidewall height as % of width)
• R — Radial construction
• 17 — Wheel diameter in inches
• 102 — Load index (1,874 lbs)
• H — Speed rating (130 mph)

For light truck tires, you might see: LT265/70R17 121/118Q E

• LT — Light Truck tire
• 121/118 — Dual load index (single/dual rear wheel configurations)
• Q — Speed rating
• E — Load Range E (10-ply equivalent)

P-Metric vs. LT Tires: Load Rating Differences

Understanding the difference between P-metric and LT tires is crucial for trucks and SUVs:

How to Choose the Right Load Rating

Step 1: Check Your Vehicle's Requirements

Look at the tire placard (driver's door jamb) or owner's manual. It lists the minimum load index and tire size.

Step 2: Consider Your Use Case

• Daily commuting, no towing — Match the OEM load index
• Occasional towing or heavy cargo — Consider one load range higher
• Regular towing or hauling — Choose Load Range D or E
• Commercial or severe duty — Load Range E or F

Step 3: Calculate Total Load Capacity

Multiply the per-tire load capacity by 4 (or by the number of tires). This should exceed your vehicle's GVWR (Gross Vehicle Weight Rating) — the maximum loaded weight including passengers, cargo, and the vehicle itself.

Example:

• Vehicle GVWR: 6,000 lbs
• Tires with load index 102: 1,874 lbs × 4 = 7,496 lbs total capacity
• ✅ Total tire capacity exceeds GVWR

Step 4: Don't Forget Inflation

Load ratings are only valid at the correct inflation pressure. An underinflated tire cannot support its rated load. Check pressures monthly and before towing.

Common Mistakes with Tire Load Ratings

1. Mixing load ranges on the same axle — All tires on an axle should have the same load range
2. Ignoring the load index when upsizing — A larger tire doesn't automatically have a higher load index
3. Underinflating LT tires — LT tires require higher pressures to achieve their rated capacity
4. Exceeding tire load capacity when towing — Remember that tongue weight adds to rear axle loading
5. Assuming "bigger is better" — Higher load range means stiffer ride; don't over-spec for your needs

Frequently Asked Questions

What happens if I use tires with a lower load index than recommended?

Using tires with a lower load index than your vehicle requires is dangerous. The tires may not support the vehicle's weight, leading to premature tire failure, blowouts, poor handling, and increased stopping distances. Always match or exceed the manufacturer's recommended load index.

Is a higher load index always better?

Not necessarily. Higher load index tires are built with stiffer construction, which can result in a firmer, less comfortable ride. They're also typically heavier, which can affect fuel efficiency. Choose the appropriate load index for your vehicle and use case — don't over-spec.

What's the difference between load index and load range?

Load index is a specific number indicating exact weight capacity per tire. Load range (a letter) indicates the tire's overall construction strength and maximum inflation pressure. Load range applies mainly to light truck (LT) tires, while load index applies to all tires.

Do I need Load Range E tires for towing?

It depends on your towing weight. For light towing (under 5,000 lbs), Load Range C or D may suffice. For heavy towing (5,000+ lbs), Load Range E is recommended. Always check that your total tire load capacity exceeds your GVWR plus trailer tongue weight.

Can I mix different load ranges on my vehicle?

It's not recommended. All four tires should ideally have the same load range for balanced handling and even wear. At minimum, tires on the same axle must match. Mixing can cause unpredictable handling, especially under heavy loads.

What does the "XL" marking on a tire mean?

XL stands for Extra Load. These passenger tires are reinforced to carry more weight than standard load (SL) tires of the same size. XL tires require higher inflation pressure (41 PSI vs. 35 PSI) to achieve their rated capacity.

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Choosing tires with the right load rating ensures your vehicle can safely handle its intended load — whether that's daily commuting or heavy towing. When in doubt, consult the tire placard on your driver's door jamb or reach out to our team.

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