The axle limit can be higher than the rubber
Truck Tire Load Limit Calculator
Calculate the lower tire-based ceiling for an axle group from usable tread width, a jurisdictional pounds-per-inch rule, tire count and sidewall ratings. It makes the binding tire rule visible beside the statutory axle number.
- Time
- Takes about 1 minute
- Privacy
- Runs in your browser
- Output
- Tire limit
Your inputs
Enter the load details
Planning result
18,000 lb across the entered tires
The tire-width rule bind first. Use the lower of the width-based allowance and combined sidewall ratings.
- Width-rule limit
- 18,000 lb
- Combined sidewall rating
- 20,000 lb
- Binding limit
- tire-width rule
What this means
- 4 tires × 7.5 in × 600 lb/in = 18,000 lb.
- 4 tires × 5,000 lb = 20,000 lb.
Assumptions
- All tires have the entered usable tread width and sidewall rating.
- Jurisdictional tire-width rules vary. Also apply axle, gross, inflation, speed and equipment ratings.
Worked example
See the calculation in plain English.
Four 7.5 in tires at 600 lb/in produce an 18,000 lb width ceiling even if the statutory single-axle limit is 20,000 lb.
What this tool does not decide
- Tire-width laws and measurement conventions vary by jurisdiction.
- Inflation pressure, speed, tire condition and equipment ratings remain separate constraints.
Common questions
Use the result without guessing.
Can tire limits be lower than a legal axle limit?
Yes. The tire-width allowance or combined sidewall ratings can bind below the statutory axle ceiling.
Is 600 lb per inch universal?
No. It is used in some rules and examples, but the applicable rate and measurement method depend on jurisdiction.