Trailer Tire Load Calculator
How much does each tire need to carry? Enter your trailer's weight, axles and hitch type — we'll do the math, including the 20% heat reserve professionals spec by.
On the trailer's VIN plate. Use loaded weight if you know it.
~10–15% of the weight rides on the hitch
Load index → pounds reference table
Per-tire capacity at maximum cold inflation pressure (industry standard table).
Need trailer tires that carry it?
Tell us your size and the capacity above — we'll quote ST trailer tires from our Orlando and Dallas stock at dealer pricing.
Common questions
Why do trailer tires need reserve capacity?
Heat is the number-one trailer tire killer. A tire running at 100% of its rated load builds heat fast, especially at highway speed in summer. The widely-taught rule is to spec tires so your real load uses no more than about 80% of their combined capacity — that 20% reserve is built into this calculator.
Where do I find my trailer's GVWR?
On the VIN/certification plate, usually riveted to the trailer frame near the tongue. GVWR is the maximum loaded weight the trailer is rated for — trailer plus everything on it.
What's the difference between Load Range C, D and E?
Load range letters reflect the tire's strength (ply rating): C = 6-ply, D = 8-ply, E = 10-ply. A higher letter carries more weight at a higher maximum pressure — the exact capacity in pounds is molded into the sidewall of every tire.
Can I use passenger car tires on a trailer?
No. ST (Special Trailer) tires have stiffer sidewalls and higher-strength construction for towing loads. Passenger tires are not designed for trailer service and can overheat and fail.
This calculator provides general guidance using industry-standard math. Always verify the maximum load and pressure molded into your tire's sidewall and your trailer manufacturer's specifications.