What does a load index of 100 mean

A tire load index of 100 means the tire can carry a maximum of 800 kilograms (1,764 pounds) per tire when properly inflated to its rated pressure and used within its speed rating. This index is a standardized code printed on the tire sidewall that indicates the tire’s load-carrying capacity; it does not represent air pressure, and it is not the vehicle’s total payload.

Understanding the tire load index

The load index is part of a tire’s “service description,” typically shown after the size (for example, 235/45R18 100Y). The number (100) is the load index, and the following letter (Y) is the speed rating. Standards bodies such as ETRTO (Europe), TRA (North America), and ISO define these indices and the exact load values they represent. The rating corresponds to the tire’s maximum load at its specified reference (maximum) cold inflation pressure and within the limits of its speed symbol.

Specifics for Load Index 100

Load index 100 is a common rating for many passenger cars and crossovers. Knowing what it means in real-world use helps you choose replacement tires correctly and avoid overloading.

The following points clarify what load index 100 means in practice:

• Capacity per tire: 800 kg (1,764 lb) when properly inflated to the tire’s rated cold inflation pressure and used within its speed rating.
• Per-tire, not per-vehicle: Four tires with LI 100 could theoretically support up to 3,200 kg (7,056 lb) combined, but your vehicle’s GVWR/GAWR still govern actual allowed weight.
• Pressure matters: The stated maximum load is achievable at the tire’s specified maximum cold inflation pressure. Vehicle placard pressures are often lower; capacity at those pressures must still meet or exceed the vehicle’s requirements.
• Speed interaction: At very high sustained speeds, some tires require load reductions. Follow the tire maker’s high-speed/load guidance if applicable.
• P‑metric on trucks/SUVs: When a P‑metric tire is used on a light truck or SUV application, industry guidelines typically require reducing its stated capacity by about 10% (derating) unless otherwise specified.
• Fitment type: Passenger and SUV tires are almost always used in single fitment. Dual-fitment load rules mainly apply to certain light-truck/commercial tires.
• Replacement rule: Do not install tires with a lower load index than the vehicle manufacturer’s recommendation. Equal or higher is acceptable.
• EVs and towing: Heavier EVs or vehicles that tow may need higher load indices to maintain adequate load reserve.

In summary, load index 100 defines the tire’s maximum supported load per tire under standardized conditions; safe use depends on proper inflation, adherence to the speed rating, and compliance with vehicle weight limits.

How to check and use the load index

Use the following steps to identify your tire’s load index and ensure your replacement tires meet your vehicle’s requirements.

1. Read the sidewall: In a marking like “235/45R18 100Y,” the number 100 is the load index and the letter Y is the speed symbol.
2. Check the vehicle placard: Found on the driver’s door jamb or in the owner’s manual; never choose a tire with a lower load index than specified.
3. Inflate to placard pressure: Use the vehicle maker’s recommended cold pressure for everyday driving; do not default to the tire’s maximum pressure unless directed by the manufacturer for a specific use.
4. Verify axle loads: Make sure the combined capacity of the tires on each axle meets or exceeds the GAWR listed on the placard.
5. Consider tire type: Light-truck (LT) tires use load ranges and detailed load/pressure tables; many also list a load index, but refer to the tables for exact capacities.
6. Account for real-world use: If you carry heavy cargo, tow, or drive an EV with higher curb weight, consider tires with a higher load index to preserve load reserve.

Following these steps ensures your tires can safely support your vehicle under normal and demanding conditions while maintaining compliance with manufacturer and industry standards.

Nearby load indices for context

To understand where load index 100 sits on the scale, here are adjacent indices and their standardized maximum loads.

• LI 98: 750 kg (1,654 lb)
• LI 99: 775 kg (1,709 lb)
• LI 100: 800 kg (1,764 lb)
• LI 101: 825 kg (1,819 lb)
• LI 102: 850 kg (1,874 lb)

These increments show that each step up or down in load index changes the tire’s maximum load by about 25 kg (55 lb) per tire in this range.

Common misconceptions to avoid

Drivers often confuse load index with other tire specifications. The points below address frequent misunderstandings.

• Load index is not air pressure: It indicates capacity, not PSI. Pressure recommendations come from the vehicle placard and tire maker’s data.
• Not an axle rating: The load index applies per tire; axle limits are set by the vehicle manufacturer (GAWR).
• XL/Reinforced vs. Standard Load: Two tires with the same load index (e.g., 100) have the same maximum load, even if one is XL. XL construction may use higher reference pressure and a different load/pressure curve—consult load tables.
• Speed and load trade-offs: High-speed operation can require load reductions; always check the tire maker’s guidance for your speed rating.

Keeping these distinctions in mind helps you select appropriate tires and set expectations for load, pressure, and performance.

Summary

A load index of 100 means each tire can carry up to 800 kg (1,764 lb) at its rated inflation pressure within its speed rating. Use it as a per-tire capacity guide, never go below the vehicle’s specified load index when replacing tires, and always adhere to the vehicle placard pressures and weight limits for safe, reliable operation.

What does a 102 load index mean?

The tire’s load index are the last 2-3 numbers before the final letter (which indicates the tire’s speed rating). Using the example P225/65 R17 102H, the load index is 102. You can then review the chart below to understand what top weight capacity this tire can safely handle (102 = 1,874 lbs).

Does a higher load index mean a rougher ride?

Higher load index tires are stiffer which can make the ride rougher. However, they are more stable with a load. Lighter load indexes tend to ride smoother but they can’t carry as much weight.

What is the load index of a tire 113 vs 117?

A tire with load index 117 can support more weight than a tire with load index 113. Load index 113 corresponds to a maximum load of 2,535 pounds per tire, while load index 117 allows for a maximum load of 2,833 pounds per tire. You should always choose tires with a load index equal to or greater than the original equipment manufacturer’s (OEM) recommendation to ensure your vehicle’s weight and cargo can be supported safely. 
Understanding Tire Load Index

• What it is: A tire’s load index is a numerical code that represents the maximum weight a single tire can support when properly inflated. 
• Higher number, higher capacity: A higher load index number indicates a greater load-carrying capacity. 
• Importance: Using a tire with a lower load index than the OEM specification means it won’t have the necessary load capacity, which can be dangerous. 

Comparing Load Index 113 and 117 

• Load Index 113: This number indicates the tire can support a maximum of 2,535 pounds.
• Load Index 117: This number indicates the tire can support a maximum of 2,833 pounds.

Key Takeaway
If your vehicle requires a load index of 117, you cannot use a tire with load index 113, as it would not be able to handle the required load.

What does load index 100 mean on tires?

The higher the tire’s load index number, the greater its load carrying capacity. Choosing a tire with a lower load index than the original equipment specifications means that the tire will not carry the load capacity of the original. Most passenger-car tire load indexes range from 75 to 100, but some are higher.