How does tire pressure affect load capacity?

The air inside the tire is what actually supports the weight of the vehicle, not the rubber itself. The higher the air pressure, the more weight the tire can push back against without the sidewalls collapsing.

Where can I find the load inflation table for my tires?

The standardized load inflation tables are published by the Tire and Rim Association (TRA). We have built these TRA standards into our calculator to provide the exact pressure-to-weight curve for your specific tire size.

Is it safe to lower tire pressure when not towing?

Yes. Dropping the pressure from 80 PSI down to 45–50 PSI when your heavy-duty truck is empty improves ride comfort and ensures the tread wears evenly. Just remember to air them back up before hooking up a heavy trailer.

What is the lowest safe pressure for an LT tire?

On a full-size pickup truck, you should generally never run an LT tire below 40–45 PSI on the highway. Dropping below this causes the stiff LT sidewalls to generate dangerous amounts of heat, risking a blowout.

Why do LT tires hold less weight at 35 PSI than standard tires?

LT tires have very thick, heavy sidewalls. They require roughly 40–45 PSI of air just to support their own structural rigidity. At 35 PSI, an LT tire is actually weaker than a thin passenger tire running at the same pressure.

LT Tire Load vs. Inflation Table

See exactly how your tire's weight-carrying capacity drops when you lower the air pressure.

Quick Answer

For a standard LT275/65R18 Load Range E tire, running the maximum 80 PSI provides a peak load capacity of 3,415 lbs per tire. If you drop the pressure to 50 PSI for a softer daily ride, the tire's capacity safely drops to 2,535 lbs — still plenty for driving an empty half-ton truck.

Select your tire's load range marking to find the correct inflation pressure. Optionally enter your current PSI to see how much load capacity you're using.

Passenger / Euro-metric tires

Light Truck (LT) tires

All load ranges — reference table

Range	Ply equiv.	Max PSI	kPa	Bar
SLStandard Load	4	35	241	2.41
XLExtra Load	—	41	283	2.83
CLoad Range C	6	50	345	3.45
DLoad Range D	8	65	448	4.48
ELoad Range Emost common LT	10	80	552	5.52
FLoad Range F	12	95	655	6.55
GLoad Range G	14	110	758	7.58

Load vs. Inflation Example (LT275/65R18 Load Range E)

Inflation Pressure (PSI)	Max Load Capacity (lbs)	Appropriate Use
35 PSI	1,940 lbs	Severely Under-inflated (Do not use)
45 PSI	2,335 lbs	Empty Truck / Daily Commuting
55 PSI	2,725 lbs	Moderate Cargo / Light Towing
65 PSI	3,085 lbs	Heavy Cargo (Load Range D Max)
80 PSI	3,415 lbs	Maximum Towing Payload (Load Range E Max)

TRA Standard

Payload decreases non-linearly as PSI decreases — standardized TRA air chamber volume tables

Air is the load bearer — the rubber casing only contains the air; it's the air pressure that supports weight
Reduce PSI when empty — running 80 PSI on an empty half-ton causes harsh ride and center tread wear
Never below 40 PSI on the highway — LT sidewalls generate dangerous heat at low pressure
Re-inflate before towing — always return to max rated PSI before hitching up a heavy load

Frequently Asked Questions

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