Truck Tire Load Ratings
Load Range vs Load Index
Two tires can share the same size but carry different markings. Load range and load index are ways to describe capacity, but they are not interchangeable labels you can ignore.
When markings differ, slow down and verify the current tire data before mixing tires on an axle.
Concept comparison
| Term | Meaning | Field note |
|---|---|---|
| Load range | A letter category (F, G, H, L...) tied to strength and maximum inflation level. | Common in truck tire conversations; G and H are most common for highway use. |
| Load index | A numeric code tied to a specific load capacity in a published table. | Often paired with speed symbol or service description. |
| Ply rating | Historical strength language, not a literal ply count in modern tires. | Still appears in shop conversations; G = 14-ply, H = 16-ply as a shorthand. |
Load range and max inflation reference
Different load ranges carry different maximum cold inflation pressures. These are the upper limits — not target pressures.
| Load range | Ply-rating shorthand | Max cold inflation (typical) | Notes |
|---|---|---|---|
| F | 12-ply | 95 PSI | Less common in standard highway commercial use |
| G | 14-ply | 110 PSI | Common steer, drive, trailer — most highway tractors |
| H | 16-ply | 120 PSI | Higher-capacity applications |
| L | 20-ply | 130 PSI | Heavy vocational and specialized applications |
How to use the markings
Use the markings to identify the tire and category, then confirm actual capacity through the manufacturer load/inflation table for the specific tire model. Do not assume two brands with the same load range letter have identical construction or application limits.
What to read on the sidewall
- Full tire size, not only the rim diameter.
- Load range letter or service description.
- Single and dual maximum load markings when both are present.
- Maximum cold inflation pressure.
- Speed symbol or application restrictions when shown.
When the two markings seem to disagree
Do not average the markings or choose the one that gives the larger number. Load range, load index, speed symbol, and manufacturer table all describe the tire under defined conditions. If a sidewall photo is unclear, ask for a closer photo or inspect the tire in person before approving a replacement.
This matters when a roadside shop offers a tire that is the right size but a different load range or load index. The tire may mount on the wheel and still be wrong for the axle load, dual service, or fleet policy.
Roadside replacement caution
In a roadside replacement, ask the service provider to read the full service description before dispatching the tire. A tire that only matches the size can still leave the truck with a lower load category than the tire it replaced.
Purchase order language
Write the full requirement on the purchase order: size, load range, service description when known, position, and whether the tire will be used single or dual. A short order such as "two 22.5 tires" invites a wrong but mountable replacement.
If a shop substitutes a different brand, ask for the data sheet or sidewall photo before approving. The replacement needs to meet the same capacity requirement, not merely fit the wheel.
Capacity Verification Checklist
- Compare the full service description.
- Check maximum cold inflation marking.
- Confirm dual rating where used.
- Use the manufacturer table for the exact tire.
- Avoid replacing one tire in a dual set with a mismatched load range.
FAQ
What load range should a semi truck tire be?
The correct load range depends on the axle load and the tire size. Load Range G (maximum 110 PSI) and Load Range H (maximum 120 PSI) cover most standard highway tractor applications. The manufacturer's load and inflation table for the specific tire model identifies the actual capacity at various inflation pressures. Confirm the load range matches the axle load requirements before purchasing.
Can I substitute a higher load range tire?
A higher load range tire is not automatically interchangeable. The rim width approval, wheel rating, and position restrictions still need to match. A higher load range also means a stiffer casing, which can affect ride and wear in some applications. Check the complete service description and manufacturer data before making a substitution.
What does ply rating mean on a modern truck tire?
Ply rating is a legacy term from the era of bias-ply tire construction. Modern radial truck tires are not built with the number of actual cord plies the rating number suggests. Today, ply rating is shorthand for a load range category — Load Range G is called 14-ply, Load Range H is 16-ply — but the load range letter is the more precise and current identifier. Use load range and the manufacturer's table for actual capacity decisions.
Source Notes
- Manufacturer Michelin Truck Tire Data Book / Load and Inflation Resources
- Manufacturer Goodyear Commercial Truck Tire Resources
- Site note TruckTireGuide.com editorial notes
Editorial Review
TruckTireGuide.com editorial team
Maintained by an independent editor with fleet tire-program experience in regional Class 8 operations, supported by transportation regulatory research and commercial vehicle technical writing.
Pages are checked against public regulations, manufacturer resources, industry references, and conservative field practice. The site does not approve tires for service or replace qualified inspection.