Overweight Axle After a Late Load Change
You are dispatched with a tandem-axle dump truck and a tri-axle trailer, permitted for a gross of 44,000 kg. The original load was 28,000 kg of gravel. At the pit, the loader operator adds 3,500 kg because "the last truck looked light." You do not have a scale ticket. The drive axles look low and the trailer axles look heavy. Your route crosses a weigh scale 15 km ahead and a bridge with a posted limit further on. You are already behind schedule.
1. How would you assess whether the truck is legal before leaving the pit?
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Without a scale ticket you are guessing, and guessing on weights is how trucks get placed out of service. The load is now 31,500 kg of gravel, and the permitted gross is 44,000 kg. Whether that is legal depends entirely on how the weight is distributed across the axle groups, not just the total.
Before leaving:
- Get a scale ticket at the pit scale or the nearest public scale. Do not rely on how the suspension looks.
- Check each axle group against its permitted limit - steer, drive, and trailer groups are rated separately.
- Check gross against the 44,000 kg permit.
"The last truck looked light" is not a weight measurement. The loader operator's guess and your visual impression are both unreliable, and the scale 15 km ahead will give you a definite answer you will not like if you are over.
2. The drive axles look low and the trailer axles look heavy. What does that suggest, and what would you do about it?
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That pattern suggests the load is sitting too far rearward, overloading the trailer group while the drive group is underloaded. That is a distribution problem, not necessarily a gross problem - the total may be legal while one group is over.
Options:
- Shift the load forward by adjusting the dump body or redistributing the gravel so the drive axles carry their share.
- Remove some material if the gross or an axle group cannot be brought within limits by redistribution.
- Re-weigh after any change to confirm each group is legal.
An overloaded trailer group is not a cosmetic issue: it increases tire and brake stress, lengthens stopping distance, and is exactly what a scale is looking for. Fix it at the pit where you have equipment, not on the shoulder of the highway.
3. What are the consequences of proceeding, and how does the posted bridge limit factor in?
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Proceeding risks several outcomes:
- At the scale, an overweight axle or gross can result in being placed out of service until the load is corrected, plus fines. Being behind schedule gets worse, not better.
- On the road, an overloaded axle group degrades braking and handling, and overloading is a contributing factor in tire failures.
- At the bridge, the posted limit is an absolute structural limit, independent of your permit. If your actual weight exceeds the posted limit, you may not cross, regardless of what your permit says. You would need to reroute or reduce the load.
The correct sequence is: weigh, redistribute or offload, re-weigh, then plan the route around any bridge limit you cannot legally meet. A permit does not override a posted bridge restriction, and a schedule does not override either.