Calculate Your Truck’s Allowable Axle Weight
Understanding your semi-truck’s allowable weight distribution is vital for safe and efficient operation. Our easy-to-use Axle Weight Distribution Calculator assists truck owners and operators in estimating their steer axle, drive axle, and trailer axle weights.
What Is Axle Weight?
Axle weight refers to the weight distributed over a single axle (or the weight spread across consecutive axle groups) of a commercial vehicle. In a semi-trailer truck, weight is typically distributed among the steer axle (front axle), drive axle (rear axle), and trailer axle (tractor weight minus total weight).
It’s important to note that this includes the truck’s gross vehicle weight plus the weight of the cargo. Overloading your axles (as specified in the manufacturer’s specs or by law) can result in:
- Fines
- Increased wear and tear on your axles
- Safety hazards
Formula Used
Drive Axle Weight = Tractor Weight − Steer Weight
Trailer Axle Weight = Total Weight − Tractor Weight
In this formula:
- Total Weight: The total weight of the truck and trailer in lbs.
- Tractor Weight: The weight of the tractor unit in lbs.
- Steer Weight: The weight on the steer axle in lbs.
- Drive Axle Weight: Calculated by subtracting the steer weight from the tractor weight.
- Trailer Axle Weight: Calculated by subtracting the tractor weight from the total weight.
Examples of Semi-Truck Axle Weights
| Total Weight (lbs) | Tractor Weight (lbs) | Steer Weight (lbs) | Drive Axle Weight (lbs) | Trailer Axle Weight (lbs) |
|---|---|---|---|---|
| 80,000 | 18,000 | 12,000 | 6,000 | 62,000 |
| 75,000 | 16,000 | 11,000 | 5,000 | 59,000 |
FAQs
How do I calculate drive and trailer axle weights for my semi using total weight, tractor weight, and steer weight?
Use two quick subtractions. Drive Axle Weight = Tractor Weight − Steer Weight. Trailer Axle Weight = Total Weight − Tractor Weight. Gather accurate readings for total, tractor, and steer, then apply the formulas.
What is axle weight on a semi-truck, and how is it different from gross vehicle weight?
Axle weight is the load carried by a single axle or a group of consecutive axles on a commercial vehicle. Gross vehicle weight is the total weight of the truck and trailer, including cargo. Axle weight focuses on distribution across axles, while gross vehicle weight is the overall sum.
What formula should I use to find drive axle weight and trailer axle weight?
Use these formulas: Drive Axle Weight = Tractor Weight − Steer Weight, and Trailer Axle Weight = Total Weight − Tractor Weight. Keep all inputs in pounds for consistency.
Example calculation: Total 80,000 lbs, tractor 18,000 lbs, steer 12,000 lbs, what are the drive and trailer axle weights?
Drive axle weight = 18,000 − 12,000 = 6,000 lbs. Trailer axle weight = 80,000 − 18,000 = 62,000 lbs.
Is there an online calculator to estimate steer, drive, and trailer axle weights?
Yes. Use our Truck Axle Weight Calculator to estimate steer, drive, and trailer axle weights from your total, tractor, and steer readings. It applies the formulas shown here to help check weight distribution.
Why does overloading an axle matter for maintenance and safety on commercial trucks?
Overloading an axle can result in fines, increased wear and tear on components, and safety hazards. Staying within manufacturer specifications and legal limits supports safer, more reliable operation.
How can I estimate trailer axle weight if I only know my total weight and tractor weight?
Subtract tractor weight from total weight. Trailer Axle Weight = Total Weight − Tractor Weight. Example: 75,000 lbs total and 16,000 lbs tractor equals 59,000 lbs on the trailer axles.
How do I compute drive axle weight from my tractor and steer readings?
Subtract the steer weight from the tractor weight. Drive Axle Weight = Tractor Weight − Steer Weight.