Axle Weight Limit Calculator
Check truck axle weights against federal and state limits. Verify steer, drive, and tandem axle compliance with FMCSA 80,000 lb GVW and per-axle regulations.
Weight Distribution Calculator
Calculate front and rear axle weights for truck loads. Ensure proper weight distribution across axle groups to comply with per-axle limits and maintain safe handling.
lbs
lbs
lbs
lbs
Steer Axle⧉
11,690 lbs
✓ Under 12,500
Drive Axle⧉
24,600 lbs
✓ Under 34,000
Trailer Axle⧉
27,710 lbs
✓ Under 34,000
Gross Vehicle Weight⧉
64,000 lbs
✓ Under 80,000
Planning notes, formulas, and examples
About the Weight Distribution Calculator
Proper weight distribution across axle groups is a legal requirement and affects vehicle handling, tire wear, and brake performance. An improperly distributed load — even if under the gross vehicle weight (GVW) limit — can overload individual axles, leading to fines, failed inspections, and unsafe handling.
The load's center of gravity and its position relative to the trailer's axle groups determine how weight distributes between steer, drive, and trailer axles. Moving the load forward shifts weight to drive axles; moving it back shifts weight to trailer axles.
This calculator estimates axle weights based on cargo placement. Enter the load weight and its position in the trailer to verify that steer, drive, and trailer axle weights all fall within legal limits.
Use the result to compare operating scenarios, pressure-test assumptions, and rerun the model when volumes, rates, or service targets change.
When This Page Helps
Overweight axle fines range from $100 to over $1,000 per violation. Beyond fines, improper weight distribution causes premature tire wear, reduced braking effectiveness, and difficulty steering. This calculator helps verify compliance before the truck reaches the scale.
How to Use the Inputs
- Enter the empty tractor weight on steer and drive axles.
- Enter the empty trailer weight on trailer axles.
- Enter the cargo weight to be loaded.
- Set the cargo placement (front, center, rear of trailer).
- View estimated axle weights for each group.
- Compare against per-axle legal limits.
Formula used
Total GVW = Tractor Weight + Trailer Weight + Cargo Weight
Trailer Axle Load = Cargo × (1 − Position Factor) + Empty Trailer Axle Weight
Drive Axle Load = Cargo × Position Factor + Empty Drive Axle Weight
Steer Axle Weight ≈ Empty Steer + Minor Adjustment
Position Factor: Front=0.6, Center=0.45, Rear=0.3Example Calculation
Result: Steer: 11,700 lbs, Drive: 24,600 lbs, Trailer: 27,700 lbs, GVW: 64,000 lbs
With cargo centered, about 45% of cargo weight transfers to drives and 55% to trailer axles. Drive: 7,500 + (38,000 × 0.45) = 24,600 lbs (under 34,000 limit). Trailer: 7,000 + (38,000 × 0.55) = 27,900 lbs (under 34,000 limit). Steer remains near 11,500-12,000 lbs. GVW = 64,000 (under 80,000 limit).
Tips & Best Practices
- Steer axle limit: 12,000-12,500 lbs. Drive tandem: 34,000 lbs. Trailer tandem: 34,000 lbs.
- Federal GVW limit: 80,000 lbs (some states allow higher with permits).
- Moving load forward 1 foot shifts ~500 lbs from trailer to drive axles.
- Use a slider (5th wheel) to fine-tune weight between drive and trailer axles.
- Weigh loads at origin if possible — it's cheaper than overweight fines on the road.
- Liquid loads shift weight dynamically — account for surge with baffled tanks.
The Bridge Formula
Federal bridge weight formula: W = 500 × [(L × N)/(N-1) + 12N + 36], where W = max weight, L = distance between axle groups, N = number of axles. This formula ensures that weight is spread out to protect bridge infrastructure. Carriers must comply with both per-axle and bridge formula limits.
Common Weight Distribution Problems
The most common issue is overloaded drive axles when freight is loaded too far forward. The second most common is overloaded trailer axles with rear-heavy loads. Both are preventable with proper load planning and pre-departure weight verification.
CAT Scales and Weigh Stations
CAT Scale locations at truck stops provide certified weights for $12-15 per weigh. If the first weigh shows overweight axles, you can reweigh after adjustments at no charge. This is far cheaper than a $1,000+ overweight fine at a weigh station.
Sources & Methodology
Last updated:
Frequently Asked Questions
FMCSA limits: Steer axle ≤ 12,000 lbs (advisory, varies by tire rating), drive tandem ≤ 34,000 lbs, trailer tandem ≤ 34,000 lbs, gross vehicle weight ≤ 80,000 lbs. Some states have stricter limits, especially on secondary roads and bridges.
The 5th wheel (kingpin pivot) connects tractor to trailer. Sliding it forward moves weight from trailer axles to drive axles. Sliding it back does the opposite. Each inch of adjustment shifts approximately 200-400 lbs between axle groups.
Overweight axle fines start at $1 per pound over in many states. For 2,000 lbs over on drives: $2,000 fine. The truck may also be placed out of service until the overweight condition is corrected, causing delivery delays and additional costs.
Options: reposition cargo within the trailer (if non-palletized), adjust 5th wheel position, remove excess freight, or redistribute pallets. The cheapest solution is to load correctly the first time using a load plan that specifies pallet positions.
Yes. The bridge formula governs how much weight can be carried based on the distance between axle groups. Wider spacing allows higher weights. Most carriers set tandems at 40-41 feet to maximize allowed GVW.
This provides reasonable estimates based on simplified physics. Actual weights vary with cargo shape, pallet placement, and vehicle specifics. Always confirm with certified scales for loads near legal limits.
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