Every trailer tire has one number that matters more than any other: its cold inflation pressure — the PSI stamped on the sidewall for a tire that has not been driven on. Get it wrong and you are either running hot toward a blowout or overinflating toward a harsh ride and a blowout on impact. Get it right and your tires run cool, wear evenly, and last their full life.
This trailer tire pressure chart walks you through the numbers by tire type and load range, explains what "cold" actually means, and shows you how to keep all eight tires on your tandem dually trailer at the correct pressure — before you roll, and while you drive.
1. What "Cold" Inflation Pressure Means
"Cold" does not mean the weather is cold. It means the tire has not been driven on for at least three hours, or has been driven less than one mile at low speed. Once a tire rolls, friction and sidewall flex raise its internal temperature, and pressure climbs with it. A tire that reads 80 PSI cold can easily read 90 PSI or more after an hour on the interstate — and that rise is completely normal.
This is why every pressure spec you will ever see is a cold spec, and why you always set and check pressure before driving. It is also why you should never bleed air from a hot tire to "correct" the number — you would be leaving it dangerously underinflated the moment it cools down.
2. How to Read Your Tire Sidewall
Your tire's sidewall carries everything you need to know, but the two things that matter for pressure are the load range letter and the max cold PSI. The load range (C, D, E, F, G) tells you the tire's strength and the pressure it is designed to run at. The max cold PSI is the ceiling — the highest pressure the tire should ever be inflated to when cold, at its maximum rated load.
For example, a tire marked "ST235/80R16 · Load Range E · Max 80 PSI" is a Special Trailer tire that should run at 80 PSI cold when carrying its full rated load. The trailer's certification label (usually on the driver's side near the front) will list the recommended pressure for the actual load, which should never exceed that sidewall maximum.
3. The Trailer Tire Pressure Chart: Load Range to PSI
This is the quick-reference trailer tire pressure chart for Special Trailer (ST) tires — the type fitted to most horse, livestock, cargo, and car-hauler trailers, including tandem dually rigs. Each load range has a standard maximum cold inflation pressure.
| Load Range | Max Cold PSI | Typical Trailer | Common Sizes |
|---|---|---|---|
| C | 50 PSI | Light single-axle and small utility trailers | ST175/80R13, ST205/75R14 |
| D | 65 PSI | Medium tandem-axle and boat trailers | ST205/75R15, ST225/75R15 |
| E | 80 PSI | Most tandem dually trailers — horse, livestock, cargo | ST235/80R16, ST235/85R16 |
| F | 95 PSI | Heavy dually trailers and toy haulers | ST235/85R16, ST235/80R16 |
| G | 110 PSI | Heaviest gooseneck and commercial trailers | ST235/85R16, ST215/75R17.5 |
4. ST vs LT: Which Chart Applies to You
Trailer tires come in two families, and they are not interchangeable. ST (Special Trailer) tires are purpose-built for trailers: stiffer sidewalls to resist the sway and scrub of a towed axle, and a load-range pressure system that tops out around 110 PSI. LT (Light Truck) tires are designed for trucks and are sometimes fitted to heavier gooseneck and equipment trailers, where they can carry higher load ranges (up to H and beyond) at higher pressures.
The practical rule: if your trailer came with ST tires, stay with ST tires and use the ST chart above. If it uses LT tires, follow the LT tire's own sidewall spec, which may run higher. Mixing the two on the same axle is never recommended — matched tires and matched pressures are part of what keeps a dual wheel running straight and cool.
Part of what surprises new trailer owners is just how high these pressures are compared to a passenger car. A car tire runs 30–40 PSI; a trailer tire runs 65–110 PSI. That higher pressure is not a quirk — it is what lets a relatively narrow trailer tire carry a multi-thousand-pound axle load without overheating. Lowering it "for a softer ride" is one of the fastest ways to destroy a trailer tire, because the extra sidewall flex at reduced pressure builds heat far faster than the tire can shed it.
5. How Temperature Changes Your Pressure
Trailer tires do not hold a constant pressure across the seasons. As a rough rule, a tire gains or loses about 1 PSI for every 10°F of ambient temperature change. Park a trailer at 80 PSI in the summer, then tow it on a crisp 40°F morning, and the tires can read several PSI low before you have driven a mile — not because of a leak, but because cold air is denser and takes up less space.
This is why "cold pressure" is checked at ambient temperature, and why a trailer that sat through a cold snap should be topped up before it moves. It is also why you should re-check pressure seasonally, not just once a year. A TPMS makes this effortless: the display shows you the live pressure on every tire, so a temperature-driven drop is visible the moment you power it on, before you reach highway speed.
Altitude compounds the effect. Higher elevations mean lower ambient pressure and colder temperatures, so a trailer towed from sea level to a mountain pass can show a noticeable drop before you ever feel a handling change. Checking and topping up at each major climate change keeps you from starting a mountain descent on underinflated tires — exactly when the extra heat of braking makes pressure loss most dangerous.
6. How to Set the Right Cold PSI
- Park and wait. Check pressure only after the tires have been stationary for 3+ hours, or driven under a mile.
- Find the spec. Read the max cold PSI and load range on the sidewall, and cross-check the trailer's certification label.
- Set every tire. Inflate all eight tires to the same cold spec — do not skip the inner duals.
- Equalize the pairs. On each dual wheel, make sure the inner and outer tires match.
- Re-check in cold weather. Top up after big temperature drops — expect about 1 PSI per 10°F.
- Verify with a TPMS. After inflating, confirm the reading on a precise monitor before you drive.
7. Keep Pressure Where It Belongs
Setting the right cold PSI is only half the job — the other half is keeping it there across a long tow. A manual gauge can tell you the pressure when you are parked, but it cannot tell you what happens at mile 200, when a slow leak, a nail, or a heat-spiked tire starts to drift. That is where a trailer tire pressure monitoring system earns its keep.
The GRUNDIG 550S TPMS monitors every tire in real time with ±1.5 PSI accuracy, so the pressure you set in the driveway is the pressure you can verify from the cab — and the pressure you will be warned about the instant it starts to fall. On an eight-tire tandem dually trailer, that is how a cold-pressure chart becomes an all-day safety net.
GRUNDIG 550S Solar Powered TPMS — Know Your Exact PSI
- ±1.5 PSI accuracy — verify your cold pressure is set correctly
- 0–200 PSI range covers every ST/LT load range on your trailer
- Real-time high/low pressure and temperature alarms
- Solar + Type-C USB display, IP67 waterproof sensors
- 6–36 wheel monitoring — all eight tires, one screen
8. Frequently Asked Questions
What PSI should a tandem dually trailer tire be set to?
Set each tire to the cold inflation pressure on its sidewall for the load range you are running. Most tandem dually trailers ride on Load Range E ST tires at 80 PSI cold, but Load Range D (65 PSI), F (95 PSI), and G (110 PSI) are also common on heavier rigs. Always read your specific tire's sidewall.
What does "cold" tire pressure actually mean?
It means the tire has not been driven on for at least three hours, or has been driven less than one mile at low speed. Cold pressure is the baseline spec; once you drive, heat raises the pressure by several PSI, which is normal and expected.
Should I inflate trailer tires to the max PSI on the sidewall?
For a trailer carrying its full rated load, inflating to the sidewall's max cold PSI is the correct and recommended practice — trailer tires are designed to run at that pressure when loaded. Do not exceed it, and do not run significantly below it under full load, because underinflation causes heat buildup and blowouts.
Why does my tire pressure drop when the weather gets cold?
Air contracts as it cools. As a rough rule, a tire loses about 1 PSI for every 10°F drop in ambient temperature. That is a normal physical effect, not a leak — but it means you should top up the tires before towing in colder weather.
Do the inner and outer tires on a dual wheel need the same pressure?
Yes. The inner and outer tires on a dual wheel must be the same size, same load range, and the same cold pressure. A mismatched pair forces one tire to carry more load, causing overheating and uneven wear.
9. The Bottom Line: Set It Cold, Then Keep It There
A trailer tire pressure chart answers the "what number" question; good habits answer the "when and how" question. Set your tandem dually trailer's tires to the correct cold PSI before every trip, re-check after any big temperature swing, and let a precise monitoring system watch the pressure while you drive. Do those three things and your tires will run cool, wear evenly, and deliver every mile they were built for.
When you pair the right cold PSI with real-time monitoring, a pressure problem can no longer hide on the far side of an eight-tire trailer. That is the whole point of the chart — and the whole point of watching it all the way down the road.
Disclaimer: This chart is a general reference. Always follow the inflation pressure stamped on your tire's sidewall and your trailer's certification label for your actual load. Never exceed the tire's maximum cold inflation pressure.