Tire Load Capacity vs Axle Weight
Will these tires hold that axle? We add the pounds from the load-index table. We do not invent an air pressure.
What it does
Looks up current and new load indexes (ETRTO single table), multiplies by 2 or 4 tires on that axle, and compares the new total to the weight you typed. Dual axles use the number after the slash when you provide it.
How to use it
Current index from the sidewall you have (91 in 91H, or 121 in 121/118R). New index from the tire you are considering. Weight is the GAWR of THAT axle on the certification sticker, or a scale ticket for that axle — never GVWR divided by four. Dual: enter the second index.
How to read the result
Covered means the table capacity of those tires at the inflation that table requires is at least the weight you entered. We do not tell you that PSI. A higher load index or load range does not “give more capacity” if you still inflate to the old pressure — especially on trailers. Operating pressure is the placard (NHTSA), not the sidewall maximum.
What this does not calculate
ETRTO single-fitment kilograms converted to pounds the same way as Load index. Dual is only the second number you type. We cannot see whether that tire is ST or LT, or whether it is the right size.
No recommended PSI. Not a towing approval. Not a substitute for weighing the vehicle.
Questions
- Why won’t you give me a PSI for towing?
- The honest PSI lives in the TRA/ETRTO load-inflation tables, which are licensed publications we do not republish. A guessed PSI for a 10,000 lb trailer is a safety failure.
- I upgraded to Load Range E on a trailer. More capacity?
- Not at the old pressure. Extra load range is unused unless you inflate to what that tire’s chart requires, still following the trailer placard rules.
- How is this different from Load index?
- Load index decodes one number into pounds and includes speed rating. This page compares a replacement against an axle weight, including duals, and refuses to output PSI.
Related tools
- Tire Load Index Chart & Speed RatingsThe number before the letter (91H) is load. The letter is speed. Both have to meet the door-jamb spec.
- Load Range to Ply Rating ConverterE is a 10-ply rating class, not ten belts. It is not a number of pounds by itself.
- PSI to kPa to Bar ConverterThe sidewall number is a maximum. The door sticker is what the car wants. Convert units here — do not mix them up.
Estimate — not a fitment approval.
