The Bridgestone Truck Tire Data Book (version 24.1) is one of the most complete public references for North American medium truck tires. Its load and inflation tables fill pages 91 to 98, but the rules that make those tables usable are scattered through the general technical section: how to check pressure, what “cold” means, when duals are matched, which rim you may use and how far apart duals must sit. This article pulls those rules together so a fleet manager can apply them without reading 118 pages. For the full pressure picture across brands, start with our truck tire pressure chart by axle load.
What the Bridgestone data book covers
The data book is organized into medium truck tires (pages 2 to 45), commercial light truck tires (pages 47 to 57), general technical information (pages 59 to 90), load and inflation tables (pages 91 to 98), technical bulletins (pages 99 to 115) and a comparison guide against competitor patterns (pages 116 to 118). The patterns are grouped by application: steer such as the R227F, R238 and R250 ED; drive such as the M726 ELA and M729F; and mixed service, trailer and regional patterns such as the M864, M840 and L317.
Every size entry shows a load range and tread depth in 32nds. For instance, the size chart lists 11R22.5 in load range G or H, and 295/75R22.5 in G or H, with tread depths from 18/32 to 32/32 depending on the pattern. The load range is your first clue to the pressure you will run, because it sets the tire’s maximum inflation.
The inflation rules Bridgestone prints in the data book
- Check and correct pressure weekly with an accurate gauge.
- Check cold. A tire is cold when the vehicle has been parked for three hours or more, or driven less than a mile at moderate speed.
- Never bleed air from a hot tire. Hot pressure rises during operation; bleeding it leaves the tire under-inflated once it cools.
- If you must adjust hot, set the tire to 10 psi (69 kPa) above the recommended cold pressure and recheck when cold.
- Investigate slow leaks. A loss of more than 4 psi (28 kPa) per month points to a damaged tire, valve, tube or rim.
- Keep duals within 5 psi. A difference of 5 psi (35 kPa) or more between duals is not recommended.
- Respect the 80 percent line. Any tire known or suspected to have run at 80 percent or less of its normal operating pressure, or to have been overloaded, may have permanent structural damage such as steel cord fatigue.
The data book also states that the inflation pressures given are the minimum pressures for the associated load. That wording matters. You can always run higher pressure up to the sidewall maximum, but you cannot run lower and still claim the stated load capacity. For more on why, see our guide to truck and bus tire pressure.
Why the 80 percent rule changes how you handle a flat
Most drivers treat a low tire as a problem solved the moment it is re-inflated. Bridgestone’s guidance says otherwise. If a tire has been run at 80 percent of its operating pressure or lower, steel cord fatigue can begin even though nothing is visible. For a 100 psi tire that threshold is 80 psi; for a 120 psi tire it is 96 psi. A tire that has been driven below that line should be dismounted and inspected inside and out before it goes back into service, or sent to a casing assessment if you plan to retread it. Our guide to hot retreading for truck fleets explains why a damaged casing can cost you a whole retread cycle.
Dual matching limits
Dual assemblies must be matched. The data book defines dual matching limits for radial tires of 0 to 1/4 inch in diameter and 0 to 3/4 inch in circumference between the two tires. Beyond those limits, one tire carries more load and works harder, which produces irregular wear, rapid wear, vehicle mechanical problems and possibly sudden tire failure. The same section states that tires of different sizes or construction must never be mixed on the same axle.
In practice, you control this with three habits. Mount new tires in pairs. Measure circumference with a tape when pairing tires of different wear stages. And keep the 5 psi pressure limit between duals. Our upcoming guide to dual pressure matching will go deeper on the diameter difference caused by a pressure gap.
Rim width and minimum dual spacing
Each size has a design rim width (shown in bold in the data book) and approved alternatives, with a minimum dual spacing for the design rim. If you use another rim width, the spacing must be adjusted: the data book notes that section width changes by 0.10 inch for each 0.25 inch change in rim width. Never use different rim widths in a dual application. Selected entries:
| Size | Design rim (in) | Other approved rims (in) | Min. dual spacing (in) |
|---|---|---|---|
| 215/75R17.5 | 6.00 HC | 6.75 HC | 9.3 |
| 245/70R17.5 | 6.75 | 7.50 | 10.6 |
| 245/70R19.5 | 7.50 | 6.75, 6.75RW, 7.50RW | 11.0 |
| 265/70R19.5 | 7.50 | 6.75, 8.25 | 11.6 |
| 285/70R19.5 | 8.25 | 7.50, 9.00 | 12.5 |
| 275/70R22.5 | 8.25 | 7.50, 9.00 | 12.2 |
| 295/75R22.5 | 9.00 | 8.25 | 13.2 |
| 295/80R22.5 | 9.00 | 8.25 | 13.2 |
| 305/70R22.5 | 9.00 | 8.25 | 13.5 |
| 315/80R22.5 | 9.00 | 8.25, 9.75 | 13.8 |
| 11R24.5 / 12R24.5 | 8.25 / 9.00 | 7.50 / 8.25 | 12.5 / 13.5 |
The 315/80R22.5 carries a dagger: an 8.25-inch rim may be used only if load is limited to 8,000 lb single and 7,610 lb dual at 120 psi, and the minimum dual spacing becomes 13.2 inches. That is a useful reminder that a rim can limit a tire’s capacity, so check both when you spec a wheel. Wide-base sizes such as 385/65R22.5 (design rim 11.75), 445/50R22.5 and 455/55R22.5 (design rim 14.00) have no dual spacing because they run single.
How to read a Bridgestone load range
Load range in the data book is shown as a letter and tread depth, for example G-24 or H-28. Load range G corresponds to a 14-ply rating and H to a 16-ply rating on the traditional scale. The higher letter means a higher maximum pressure and a higher load rating for the same size, so H is the usual choice when axles run near their limit. Our deeper comparison arrives in a dedicated guide on load range G versus H, and our existing article on 11R22.5 pressure by axle load gives practical figures today.
A weekly routine that follows the data book
- Check every tire cold, before the first trip of the day.
- Record each reading with the tire position, not just the truck.
- Correct to the load-based cold pressure, not the maximum on the sidewall.
- Compare duals and fix any pair 5 psi or more apart.
- Flag any tire losing more than 4 psi per month for inspection.
- Log any tire found at 80 percent of target or lower for dismounting.
This routine costs a few minutes per truck and protects the casing value that drives your total cost of ownership. Fleets that fit tire pressure monitoring systems can automate the weekly check, but the rules about cold pressure and the 80 percent line still apply to the alerts they generate.
FAQ
Does Bridgestone publish the same pressure for steer and drive tires?
No. Pressure is set by load, not by position. A steer axle on a heavy tractor may need higher pressure than a lightly loaded drive axle. Use the load and inflation table for each axle weight.
Can I top up a hot tire to the cold pressure on the placard?
Not accurately. Hot tires read higher because of heat. Bridgestone suggests setting a hot tire 10 psi above the cold target and rechecking when it cools.
What happens if duals differ by more than 5 psi?
The higher-pressure tire has a larger rolling diameter and carries more of the load, so it wears faster and runs hotter. The lower-pressure partner scrubs and wears irregularly.
Key takeaways
The Bridgestone data book is valuable because it combines tables with rules: weekly cold checks, a 10 psi hot adjustment, a 4 psi per month leak alert, a 5 psi dual limit and the 80 percent damage line. Pair those with correct rim widths and dual spacing and you remove the most common causes of premature tire loss. Continue with our pressure management hub for the rest of the cluster.
