Right after the wheel diameter in a tire size, you'll see a two- or three-digit number — the load index. It tells you the maximum weight that one tire can safely carry at its maximum cold inflation pressure. Get this number wrong and your tires can fail under a heavy load.
Common load indexes for passenger vehicles
- 82 — 1,047 lbs (small car)
- 87 — 1,201 lbs (compact)
- 91 — 1,356 lbs (midsize sedan)
- 95 — 1,521 lbs (small crossover)
- 100 — 1,764 lbs (midsize SUV)
- 105 — 2,028 lbs (full-size SUV)
- 112 — 2,469 lbs (heavy SUV / light truck)
- 116 — 2,756 lbs (large pickup)
- 121 — 3,196 lbs (heavy-duty truck)
How to find your required load index
Look at the size string on the door-jamb sticker. It includes the load index your manufacturer specified. Example: 235/65R17 104H means your car was designed for a load index of at least 104.
Going up vs going down
Going up in load index is always safe — a tire rated to carry more than required is fine. Going down is never safe. A tire rated for less than the manufacturer specified can overheat and fail under your car's weight, especially when fully loaded.
Why this matters more for SUVs and trucks
A loaded family minivan with seven people, luggage, and a roof box can weigh 6,500 lbs. If each tire is carrying 1,625 lbs and your load index is 100 (1,764 lbs), you're at 92% of rated capacity. If you replace with a load index of 95 (1,521 lbs), you're at 107% — overloaded.
Inflation matters
The load index is rated at the tire's maximum cold inflation pressure (printed on the sidewall, usually 44 or 50 PSI). At lower inflation, the tire carries less. This is one reason why running the right pressure matters — under-inflated tires are de-rated.
Extra load (XL) tires
Some passenger tires are marked XL or Reinforced. They have higher load indexes at the same size and a higher maximum pressure (usually 50 PSI). If your vehicle calls for an XL tire, don't substitute a non-XL tire of the same size.
Load index isn't optional. It's the maximum your tire can hold.