How to Find the Right Tire Load-Inflation Table Using Your Sidewall Markings

The right tire load-inflation table depends on three things printed on the tire sidewall: the size prefix or suffix (P, none, LT, ST or a flotation format), the load designation (standard load, XL or a load range letter) and the exact size. Together these tell you which industry standard the tire was built to. That standard determines which table shows how much weight the tire carries at each cold inflation pressure. Bridgestone, Continental, Cooper, Falken, General Tire, Goodyear, Toyo Tires and other brands publish these tables, and they are generally built on the same standards. Matching the tire type and load designation therefore matters more than which brand's chart you open.

What is a tire load-inflation table?

A tire load-inflation table lists the maximum load one tire can carry at a range of cold inflation pressures for a given tire size and type. Load is given in kilograms or pounds. Pressure is given in kPa or psi, and sometimes in bar. The table has a row for each tire size and a column for each pressure. Where the row and column meet, you read the load capacity per tire.

The tables come from tire standards organizations. In the United States this is The Tire and Rim Association (TRA). In Europe it is the European Tyre and Rim Technical Organisation (ETRTO), and in Japan it is the Japan Automobile Tyre Manufacturers Association (JATMA). Tire makers reproduce these values in their technical data books and online. That is why a Goodyear tire load inflation table and a Bridgestone tire load inflation table for the same P-metric size normally agree.

Load-inflation tables do not replace the vehicle placard on the door jamb. The placard gives the recommended cold pressure for the original tire size. The table matters when you change tire size or tire type, or when you need to check that a replacement tire supports at least the same load as the original.

Which sidewall numbers tell you which table to use?

The sidewall size code is made up of dimensions, a ratio, a construction code, a rim size and service ratings. Only some of these choose the table, but you need all of them to find the right row.

Marking (example P225/65R17 102H)	Type of value	What it means	Role in finding the table
P	Tire type prefix	P-metric passenger tire (TRA standard). No prefix usually means a Euro-metric (ETRTO) tire.	Selects the table family
225	Dimension (millimetres)	Nominal section width, sidewall to sidewall, on a specified measuring rim	Part of the size row
65	Ratio (percent)	Aspect ratio: sidewall height is 65% of the section width	Part of the size row
R	Construction code	Radial construction	Part of the size row
17	Dimension (inches)	Wheel rim diameter the tire fits	Part of the size row
102	Performance rating (load index)	Code for maximum load per tire: 102 = 850 kg (1,874 lb)	Confirms the maximum value in the row
H	Performance rating (speed symbol)	Maximum speed category under specified conditions: H = 210 km/h (130 mph)	Not used to read load from pressure
XL, Extra Load, RF or Reinforced	Load designation	Higher-load version of a passenger tire that needs more pressure to reach its maximum load	Selects the XL column or table
Load Range C, D, E or F	Load designation	Strength class for LT and ST tires, linked to a maximum load pressure	Selects the load range row
Max load ... at max press ...	Units of load and pressure	Maximum load the tire can carry and the maximum cold pressure molded on the sidewall	Upper limit; not a recommended pressure

Mixed units are normal in tire sizes. Section width is in millimetres, aspect ratio is a percentage and rim diameter is in inches. The load index and speed symbol are codes, not measurements. You convert them using the standard load index and speed symbol charts.

How to read the maximum load and pressure line

The line "Max load 850 kg (1874 lbs) at 300 kPa (44 psi) max press" gives two limits. The first is the most weight the tire may carry. The second is the highest cold pressure the tire is designed to hold. On a standard-load passenger tire, the maximum load is usually reached at a lower pressure than the molded maximum. Above that point, the load-inflation table shows no further increase in load.

Which tire load-inflation table matches my tire type?

Each tire family has its own table because the same nominal size can carry different loads at the same pressure depending on how the tire is built and rated.

Sidewall format	Tire family	Load designation	Pressure at which maximum load is commonly reached
P225/65R17 102H	P-metric passenger (TRA)	Standard load	35 psi
P225/65R17 106H XL	P-metric passenger (TRA)	Extra load	41 psi
225/65R17 102H	Euro-metric passenger (ETRTO)	Standard load	250 kPa (36 psi)
225/65R17 106H XL	Euro-metric passenger (ETRTO)	Extra load or reinforced	290 kPa (42 psi)
LT245/75R16 120/116S	LT-metric light truck	Load Range C, D, E or F	C: 50 psi, D: 65 psi, E: 80 psi, F: 95 psi
31x10.50R15LT 109S	Flotation light truck	Load range (often C)	Depends on load range; check the flotation table
ST225/75R15	Special Trailer (trailer tires)	Load Range C, D or E	Pressure for the load range shown on the sidewall

Some newer tire load inflation tables also include an HL (high load capacity) designation. HL tires carry more load than XL tires of the same size. If your tire shows HL, use the HL values, not the standard or XL values.

Why P-metric and Euro-metric tables are not interchangeable

A P-metric P225/65R17 and a Euro-metric 225/65R17 share nominal dimensions but come from different standards. Their loads at a given pressure can differ slightly, and their maximum load pressures differ. When you replace one with the other, read each tire from its own table. Then compare the load capacities at the pressure you plan to use.

Under TRA guidance, a P-metric tire fitted to a light truck, SUV or trailer has its rated load reduced by dividing by 1.10. This is roughly a 9% reduction. Euro-metric tables have no single equivalent rule that applies everywhere, so check the tire maker's guidance for that use.

How LT tires show single and dual loads

An LT tire such as LT245/75R16 120/116S has two load indexes. The first (120 = 1,400 kg or 3,086 lb) applies when the tire is mounted singly. The second (116 = 1,250 kg or 2,756 lb) applies when it is mounted in a dual pair. An LT load-inflation table lists both values, so read the column that matches how the tire is mounted.

How do I find the correct row and column?

To find load capacity at a given pressure, follow these steps:

1. Write down the full size from the sidewall, including any prefix (P, LT, ST, T), any suffix (LT or C) and the load designation (XL, RF, HL or a load range letter).
2. Identify the tire family from the comparison table above. Examples are P-metric standard load, Euro-metric XL, LT-metric Load Range E and ST Load Range D.
3. Open a tire load inflation chart for that family. A Continental, Toyo, Falken or Cooper table works if it covers the same family and designation.
4. Find the row that matches the exact size, for example 225/65R17. Find the sub-row for the load designation if the table splits sizes that way.
5. Move across to the cold inflation pressure column you want to check. Read the load per tire in kilograms or pounds.
6. Confirm that the value at the highest listed pressure matches the load index on the sidewall. If it does not, you are probably in the wrong table or row.
7. Compare the load per tire with what that axle needs. A simple check is the axle weight rating divided by the number of tires on that axle. The replacement tire's load at your chosen pressure should be at least equal to the original tire's load at the placard pressure.

Load values always refer to cold inflation pressure. This is the pressure measured before driving, or after the tire has cooled. Do not inflate above the maximum pressure molded on the sidewall. Also do not set the pressure below the value the table shows is needed for the load being carried.

Pressure units used in tire load-inflation tables

North American tables usually list pressure in psi. ETRTO-based tables usually use kPa or bar. 1 bar equals 100 kPa, which is about 14.5 psi. For example, 250 kPa is 2.5 bar or about 36 psi. Loads convert at 1 kg = 2.205 lb.

Do Bridgestone, Continental, Cooper, Falken, General, Goodyear and Toyo tables differ?

For the same size, tire family and load designation, brand load-inflation tables normally show the same values. They are derived from the same TRA, ETRTO or JATMA standards. A Toyo Tires load inflation table and a General Tire load inflation table for a Euro-metric XL size should therefore lead to the same load at the same pressure.

Brand tables can differ in what they contain:

• Coverage: a brand table may list only the sizes and load designations that brand makes.
• Pressure steps: pressure columns may use different steps or units.
• Product guidance: some makers add notes for their own product lines, such as trailer use or high-load designs.

If two tables disagree for what looks like the same tire, check the size prefix and load designation again before assuming the brands differ.

How do trailer tire load-inflation tables work?

Trailer tire load inflation tables cover ST (Special Trailer) tires. Their load values are not the same as P-metric or LT values for similar nominal sizes. An ST tire such as ST225/75R15 has a load range letter that sets its maximum load pressure. The ST table lists the load each load range carries at each pressure up to that limit.

Points specific to trailer tires:

• Single and dual loads: ST tables list load per tire for single fitment and, where applicable, dual fitment.
• Speed limits: under TRA practice, older ST tires without a speed symbol were rated for 65 mph (105 km/h). Newer ST tires may carry a speed symbol, and the maker may specify a different load at higher speeds.
• Pressure advice: many trailer tire makers advise running ST tires at the maximum pressure on the sidewall. Check the specific maker's guidance for your tire.
• Do not mix families: if you replace ST tires with LT or passenger tires, read each tire from its own table. Confirm that the replacement carries the required load at its rated conditions.

How do size changes affect sidewall height, diameter and circumference?

Width, aspect ratio and rim diameter together set a tire's sidewall height and overall diameter. A size change can therefore alter both geometry and load capacity, which is why the table lookup must use the exact new size.

Simple calculations from the size code

• Sidewall height (mm) = section width (mm) × aspect ratio ÷ 100
• Overall diameter (mm) = 2 × sidewall height + rim diameter (inches) × 25.4
• Circumference (mm) = overall diameter × π (about 3.1416)
• Approximate revolutions per mile = 1,609,344 ÷ circumference (mm)

Example for 225/65R17:

• Sidewall height = 225 × 0.65 = 146.25 mm
• Overall diameter = 2 × 146.25 + 17 × 25.4 = 292.5 + 431.8 = 724.3 mm, about 28.5 in
• Circumference = 724.3 × 3.1416 ≈ 2,275 mm
• Revolutions per mile ≈ 1,609,344 ÷ 2,275 ≈ 707

Comparing two sizes on the same rim

Size	Sidewall height	Overall diameter	Circumference	Difference vs 225/65R17
225/65R17	146.3 mm	724.3 mm (28.5 in)	2,275 mm	Reference
235/60R17	141.0 mm	713.8 mm (28.1 in)	2,242 mm	About 10.5 mm smaller in diameter (−1.4%)
235/65R17	152.8 mm	737.3 mm (29.0 in)	2,316 mm	About 13 mm larger in diameter (+1.8%)

The comparison shows how each value works:

• Wider tire, lower aspect ratio: 235/60R17 is wider than 225/65R17, but its lower aspect ratio gives a shorter sidewall and a smaller overall diameter.
• Wider tire, same aspect ratio: 235/65R17 keeps the 65 ratio on a wider base, so its sidewall and overall diameter both grow.
• Rim diameter: on any size, rim diameter adds directly to overall diameter, 25.4 mm for each inch.

A difference in circumference changes how far the vehicle travels per wheel revolution. This affects speedometer and odometer readings.

Why size changes matter for load capacity

Different sizes have different rows in the load-inflation table and often different load indexes. When you change size, look up the new size in the correct table. Find the pressure at which it carries at least the load the original tire carried at the placard pressure. If the new size cannot reach that load within its maximum pressure, it does not provide equivalent load capacity.

What are the limits of calculated tire dimensions?

Calculated geometry is a nominal estimate, not the actual measured tire dimensions. Actual dimensions vary for several reasons:

• Measuring rim: section width is defined on a specified measuring rim, and a wider or narrower wheel changes the mounted width.
• Design and tread: tread depth, tread design and construction vary between brands and models of the same size.
• Load and pressure: the tire's loaded radius under the vehicle is smaller than its free, unloaded radius.
• Wear: tread wear reduces overall diameter over the tire's life.

For actual values, use the manufacturer's specification for that exact tire model. Spec sheets typically list measured overall diameter, section width, approved rim width range and revolutions per mile.

Calculated geometry and load-inflation values also do not confirm vehicle fitment compatibility. Fitment depends on several further factors:

• clearance to suspension, brakes and bodywork through full steering and suspension travel
• an approved rim width for the wheel
• load index and speed rating at least equal to the vehicle requirement
• the vehicle maker's approved sizes

A load-inflation table tells you what a tire can carry at a given pressure. It does not tell you whether that tire belongs on a particular vehicle.