Trailer Tire Load Range Chart

How to use this chart

1. Read the size off the sidewall. Trailer tires start with ST, for Special Trailer, then the size: ST225/75R15. Pick that from the dropdown.
2. Pick the load range letter. It is the single capital letter on the sidewall, usually near the size or the max pressure. Only the letters your size is actually sold in appear as options.
3. Say how many tires are on the ground. Two for a single axle, four for a tandem, six for a triple. Spares do not count.
4. Type what the trailer weighs loaded. Optional, but it is where the chart stops being a reference and starts being an answer. Use a scale ticket if you have one, the GVWR off the trailer's plate if you do not.
5. Take it with you. Share copies a link that reopens on these exact numbers. PDF gives you the whole table on one landscape page for the toolbox or the build thread.

Why this chart is different

Search this and you get a dozen pages that all tell you the same thing: Load Range D means 8-ply and 65 psi. True, and almost useless. It does not tell you whether your trailer is safe, because capacity is not a property of the letter. It is a property of the letter and the size together. A Load Range D in a 13-inch tire carries 1,570 lb. A Load Range D in a 16-inch tire carries 3,000 lb. Same letter, nearly double the load.

• Capacity by size, not just by letter. The full industry-standard ST load table, every size against every pressure from 15 to 80 psi. That is the number the rest of page one leaves out.
• A verdict, not a lookup. Enter your loaded weight and get the margin in pounds and as a percentage, with a plain answer about whether it is comfortable, adequate, thin, or over.
• We tell you where the sources disagree. Carlisle rates its ST235/80R16 Load Range E a hundred pounds above the standard table. Rather than quietly pick one, the chart shows the standard figure and says who rates it higher. Nobody else on this SERP mentions that manufacturers vary at all.
• Manufacturer-rated sizes are kept separate. ST235/85R16 and the other newer sizes are not in the standards table. They are in a clearly labelled second block, so nothing on this page implies a standard that does not exist.
• A real printable PDF. One landscape page, the whole table, date-stamped and signed. People search for this chart as a PDF and the results give them a screenshot of a screenshot.
• Embeddable. Trailer forums, RV clubs, boat and horse-trailer boards, dealer service pages. One line of HTML, free, attribution included.

How load range, ply rating and capacity actually work

Three labels describe the same property, which is why the topic is confusing. The ply rating is the oldest: back when tires were cotton cord, you counted the layers. A modern radial called "10-ply" does not have ten of anything. It has the strength the old ten-layer construction had. The load range letter replaced the count: B, C, D, E, F, each step adding two plies of equivalent strength and raising the maximum cold inflation pressure.

Neither of those is a capacity. The capacity comes from the load and inflation table, which pairs a tire size with a pressure and gives the pounds that tire may carry. The load range letter just marks where that size's table stops. Load Range C ends at 50 psi, D at 65, E at 80. Look up ST205/75R15 at 50 psi and you get 1,820 lb, and that is the Load Range C rating for that size. The letter is an index into the table, not the answer itself.

Multiply by the number of tires on the ground and you have what your axles can carry. A tandem-axle trailer on ST225/75R15 Load Range D is four tires at 2,540 lb, or 10,160 lb of tire. If the trailer scales at 8,000 lb loaded, you have 2,160 lb of margin, about 27%. That is a healthy number. Under about 10% and you are one wet cooler and a full water tank away from running at the limit.

The trailer tire pressure rule that catches people out

On your truck or car, the load and inflation table is a licence to run less air when you are carrying less. On trailer tires it is not. ST tire manufacturers direct owners to inflate to the maximum cold pressure printed on the sidewall regardless of load, because trailer tires run at high load-cycles and heat is what destroys them, not pressure. This chart reports the lowest pressure at which your tire is rated for a given load, which is useful for understanding margin. It is not permission to run that pressure. Set them cold, at the sidewall number, and check them before every tow with something that actually reads that high — plenty of pocket gauges stop at 50 psi, which is a problem when the sidewall says 80. Our roundup of the best tire pressure gauges covers which ones hold accuracy at the top of their range.

Speed, and the 65 mph number

The published ST load limits are established at 65 mph — Goodyear prints exactly that at the head of its ST table. This is where the old "trailer tires are only good for 65" rule comes from, and for a tire with no speed symbol it still holds. Many modern ST radials are rated higher: Carlisle's Radial Trail HD line runs 75 to 87 mph depending on the size, and the Maxxis M8008 is rated 81. Read your own sidewall rather than trusting the rule of thumb in either direction. We deliberately do not publish a de-rating percentage for going faster than 65, because it varies between manufacturers and there is no single standard to cite. A made-up number on a safety calculation is worse than no number.

Load range C vs D vs E on a trailer

This is the question behind most searches, and the honest answer is that it depends on the size, which is why a letter-only comparison misleads. Here it is in ST225/75R15, the most common trailer size in North America:

• Load Range C — 6-ply, 50 psi, 2,150 lb per tire. A tandem carries 8,600 lb. Fine for light utility and small boat trailers. Where people get into trouble is a boat plus trailer creeping toward 3,500 lb on a single axle: two Load Range C tires in a smaller size may not cover it.
• Load Range D — 8-ply, 65 psi, 2,540 lb per tire. A tandem carries 10,160 lb. This is the working default for travel trailers, horse trailers and enclosed cargo, and it is the load range most tandem trailers in the 7,000 lb class leave the factory on.
• Load Range E — 10-ply, 80 psi, 2,830 lb per tire. A tandem carries 11,320 lb. Worth it for heavy travel trailers, car haulers and anything that tows near its plate every trip. You give up ride quality and you gain margin.

The rule Mike uses in the bay: buy the load range that leaves you at least 20% of margin at your real, loaded, scale-ticket weight — not your empty weight and not the brochure. Trailer tires fail from heat and age far more often than from a nail, and heat is what running near the limit produces. Going up one letter is one of the cheapest safety upgrades on a trailer, and if you are replacing all four anyway, our tire brand guide covers which manufacturers hold their rating in trailer service.

Worked examples

Tandem travel trailer, 8,000 lb loaded, ST225/75R15 Load Range D. 2,540 lb per tire, 10,160 lb across four. Margin is 2,160 lb, or 27%. Comfortable. Per tire you are carrying 2,000 lb, which the table first covers at 45 psi — but you still run the 65 psi on the sidewall.

Single-axle utility trailer, 3,400 lb loaded, ST205/75R15 Load Range C. 1,820 lb per tire, 3,640 lb across two. Margin is 240 lb, about 7%. Rated, but thin: one heavy pallet and you are over. This is the case for going to Load Range D, which takes the same size to 2,150 lb per tire and the margin to 26%.

Boat trailer, 3,000 lb loaded, ST175/80R13 Load Range C. 1,360 lb per tire, 2,720 lb across two. That is 280 lb over. No pressure fixes it, because 50 psi is already the top of Load Range C in that size. The fixes are a higher load range, a bigger size, or a second axle.

Tandem equipment trailer, 12,000 lb loaded, ST235/80R16 Load Range E. 3,420 lb per tire, 13,680 lb across four. Margin is 1,680 lb, 14%. Adequate, and worth watching if the load ever grows.

Frequently asked questions

Which is better, a load range C or D trailer tire?

D, if your trailer's weight justifies it, and it usually does. In ST225/75R15, D carries 2,540 lb per tire against C's 2,150 — about 18% more, for a modest price difference. C rides slightly softer at its lower 50 psi. The only real reason to stay on C is that your trailer is light and you value ride over margin. If you are within 10% of your tires' total rating on C, move up.

What's better, load range D or E?

E carries more: 2,830 lb versus 2,540 lb per tire in ST225/75R15, at 80 psi instead of 65. Whether it is better depends on your weight. If your loaded trailer already sits at 25% margin on D, E buys you comfort you may not need and a firmer ride. If you tow near the plate, E is the right call. Going up a load range does not raise your trailer's legal GVWR — the axles, frame and brakes set that. It only removes the tires as the weakest link.

What are the load ranges on trailer tires?

B, C, D, E and F cover essentially all trailer service. B is 4-ply equivalent at 35 psi, C is 6-ply at 50, D is 8-ply at 65, E is 10-ply at 80, F is 12-ply at 95. Not every size is sold in every letter: 13-inch ST tires stop at C in the standards table, and only the largest sizes reach F.

Is 8 ply or 10 ply better for a trailer?

Same question as D versus E, since 8-ply equivalent is Load Range D and 10-ply is Load Range E. Neither tire has that many actual layers. The 10-ply carries roughly 11% more in a given size and runs 15 psi harder. Buy the one that leaves margin at your real weight.

Can I put LT truck tires on my trailer instead?

Physically often yes, and plenty of people do it, but the capacities are not interchangeable and an LT tire of the same nominal size usually carries less than the ST version. ST sidewalls are also built stiffer to resist the sway and scrub a trailer axle puts through them. If you swap, work from the LT tire's own load table and its own numbers, not this chart.

Should I run less than the maximum pressure if my trailer is light?

No. This is the biggest difference between trailer tires and the tires on your tow vehicle. ST tire manufacturers direct maximum cold sidewall pressure regardless of load. The load and inflation table here tells you what a tire is rated to carry at a pressure; it is a margin tool, not a licence to run soft. Underinflated trailer tires build heat, and heat is the failure mode that strands people.

Related tools

• Tire Ply Rating + Load Index Chart — decodes any sidewall, trailer or not, including the load index number this chart does not use.
• Towing Capacity Calculator — the other half of the question: what your tow vehicle can pull, not what the trailer's tires can hold.
• Recommended Tire Pressure Lookup — for the tow vehicle, where the run-max-sidewall rule does not apply.
• Tire Diameter Calculator — checking fender and frame clearance before you go up a size.
• Browse all free tools by Mike Reeves →

Mike's recommendations for trailer tire work

Three things make the difference between a chart and a trailer that actually arrives:

• Best Tire Pressure Gauges — most gauges in a glovebox top out around 50 psi. A Load Range E trailer tire wants 80, and a gauge reading past its range is guessing at exactly the moment accuracy matters.
• Best Tire Inflators — same problem, worse. A lot of portable inflators lose the will to live somewhere in the sixties. Check the rated pressure and the duty cycle before you are relying on it at a boat ramp.
• Best Tire Brands — trailer tires usually age out before they wear out, so who made them matters more than tread depth. This covers which brands hold up in trailer service.

And if a trailer tire does let go on the road, the flat-tire walkthrough and a set of jack stands that will actually hold a loaded trailer are what you want to have sorted in advance.

Sources & methodology

• Goodyear — Tire Inflation & Load Charts — the "Special ST Metric Tires for Trailers in Highway Service" table, sourced from Tire and Rim Association and ETRTO data. This is the spine of the chart.
• Goodyear — Load/Inflation Information for RV ST Metric Tires — the same table extended down to 15 and 20 psi, and the printed 65 mph maximum speed rating.
• Maxxis — M8008 ST Radial load limits — an independent publication of the same table, used as a cross-check.
• Carlisle (Carlstar) — Radial Trail HD specifications — per-SKU rated load, pressure and speed. Source for the manufacturer-rated sizes and the documented ST235/80R16 variance.

Every figure in the standard table appears in four independent publications. Two Goodyear charts, Maxxis and Carlisle were compared cell by cell. Carlisle matched the standard on nine of the ten size and load-range pairs it shares with the table; the tenth, ST235/80R16 Load Range E, is disclosed on the page rather than resolved silently. Sizes with no entry in the standards table are labelled as manufacturer-rated and attributed.

The table, the capacity maths and the verdict thresholds are asserted by fixtures.test.mjs next to the tool's data file, and the test runs before the site can build. It reproduces all 77 published load limits, proves no row runs backwards, checks every load-range marker sits at the pressure the letter table specifies, confirms the minimum-rated-pressure lookup never interpolates a value the standard does not publish, and requires every verdict tier to be reachable from a real input. About Mike Reeves · Last reviewed September 11, 2026.

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  Trailer tire load range chart by
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  &middot; Reviewed by Mike Reeves, ASE Master Technician
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