The load index on a tire is a two or three-digit number indicating the maximum weight the tire can safely carry. You will find it immediately after the size code on the sidewall — in 225/50R17 94H, the 94 is the load index. Here is what the numbers mean and why going below your vehicle spec is a safety problem.
How to read the load index
The load index is not a weight in pounds or kilograms — it is a code that corresponds to a weight in a standardized chart. Key reference points: 85 = 1,135 lbs per tire; 87 = 1,201 lbs; 91 = 1,356 lbs; 94 = 1,477 lbs; 97 = 1,609 lbs; 100 = 1,764 lbs; 105 = 2,039 lbs; 110 = 2,337 lbs; 114 = 2,601 lbs; 121 = 3,197 lbs.
For a vehicle with four tires at load index 97 (1,609 lbs each), the total rated tire capacity is 4 times 1,609 = 6,436 lbs. Most passenger vehicles weigh significantly less than this, which is why passenger car tires are rarely the limiting factor in load carrying.
XL — Extra Load designation
Some tires carry an XL or Reinforced designation alongside the size code (for example, 235/45R18 98W XL). XL tires are constructed to handle a higher maximum pressure and corresponding higher load than a standard tire of the same size.
XL tires are increasingly common on larger passenger cars and performance vehicles that push the limits of the standard load rating. If your door sticker calls for XL-rated tires, do not substitute standard tires — they cannot be inflated to the higher pressure needed to achieve the load rating.
Why load index matters more on heavy vehicles
For a 3,500-lb passenger car, load index is rarely the binding constraint. For a 5,800-lb body-on-frame SUV or a truck towing a trailer, load index matters significantly. Running tires with a load index below spec on a heavy vehicle creates a risk of heat buildup, sidewall flex overload, and tire failure under load.
Always check the door sticker for the minimum load index specified by the manufacturer. When in doubt on a heavy vehicle or when towing: match or exceed. Never substitute a lower load index for a price discount.
Frequently asked
What is a good load index for a tire?
There is no universally good load index — match or exceed what your vehicle specifies on the door sticker placard. For most passenger cars, load index 87 to 97 is typical. For trucks and large SUVs, 110 to 121 is more common.
Can I use a tire with a higher load index than specified?
Yes — installing a higher load index tire than your vehicle requires is safe and has no downsides. You cannot go lower without losing safety margin.
What does XL mean on a tire?
XL (Extra Load) means the tire is built to handle a higher inflation pressure and corresponding higher maximum load than a standard tire of the same size. If your vehicle specifies XL tires, you must use XL-rated replacements — a standard tire cannot be inflated to the same pressure.
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Last updated 2026-06-27. General guidance only — confirm specifics with a local shop for your exact vehicle.