How to read weight figures and examples
- Ratings are maximum limits, not measurements of your loaded setup. Confirm the exact variant and approved ratings.
- Measure loaded coupling weight. A percentage or the difference between ATM and GTM ratings does not establish today's coupling weight.
- An added load changes both axle reactions according to its position. A change is not a total axle load; use measured starting axle weights and add each load once.
- Combination mass is unhitched loaded vehicle plus total loaded trailer, or the sum of all coupled axle readings. Count coupling mass once.
- Examples and AI suggestions are planning aids, not verified measurements or compliance clearance. Unknown figures require measurement; active weight-distribution hitches and gooseneck arrangements need their own assessment.
Introduction
A weighbridge ticket is the only reliable way to know the actual weight of your vehicle and caravan. Estimates and brochure figures can be significantly different from reality — and it is the actual weight, not the published figure, that determines whether your setup is within legal limits.
This guide explains what each measurement on a weighbridge ticket means, how to interpret the numbers against your vehicle and caravan limits, and when to seek professional advice.
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What a Weighbridge Measures
A weighbridge is a large platform scale that measures the weight pressing down on it. When you drive onto it, the weighbridge records the weight of whatever is on the platform.
Most public weighbridges can provide:
Not every weighbridge can provide all of these. Some provide only a single gross weight. Others have segmented platforms that can measure individual axles. Ask the operator what measurements are available before you start.
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Vehicle-Only Measurement
Weighing the tow vehicle by itself (without the trailer attached) gives you the actual loaded vehicle weight.
**How to do it:**
1. Unhitch the trailer (or never hitch it in the first place)
2. Drive the vehicle onto the weighbridge so all wheels are on the platform
3. Record the gross weight — this is your actual loaded vehicle weight
4. If the weighbridge has segments, also record individual axle weights
**What it tells you:**
- Compare the total to your vehicle's **GVM** — if the actual weight exceeds GVM, the vehicle is overloaded
- Compare front axle weight to the **front axle rating**
- Compare rear axle weight to the **rear axle rating**
**Why it matters:** Actual loaded vehicle and axle measurements establish whether the setup exceeds the applicable GVM or axle limits. Use an appropriate weighbridge or calibrated scales, and compare each reading against the exact manufacturer or engineering limit.
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Combination Measurement
Weighing the tow vehicle and trailer together gives you the combined weight — which you compare against your vehicle's **GCM**.
**How to do it:**
1. Hitch the trailer to the vehicle
2. Drive the entire combination onto the weighbridge so all wheels (vehicle and trailer) are on the platform
3. Record the total — this is your combination weight
**What it tells you:**
- Compare the total to your vehicle's **GCM** — if the combination weight exceeds GCM, the setup is non-compliant
**Why it matters:** GCM is a separate limit from GVM and tow rating. A vehicle and trailer that each individually comply with their own limits can still exceed GCM when combined. This measurement confirms whether the combination is within the legal combined weight.
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Axle Measurements
If the weighbridge can measure individual axles, you get the most useful data — because axle ratings operate independently of overall GVM.
**Key measurements to record:**
**How axle measurements work with towing:**
When you hitch a trailer, the towball mass pushes down on the rear of the vehicle. This:
- Increases the **rear axle load** on the tow vehicle
- May decrease the **front axle load** on the tow vehicle (weight transfers from front to rear)
- The trailer tyres support actual trailer axle mass; compare it with the GTM and axle ratings. Do not substitute rated ATM for a measured total
**Why it matters:** You can be within GVM but over a rear axle rating. This is one of the most common compliance issues in modified touring setups. Axle measurements are the only way to detect it.
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Towball Mass Measurement
Some weighbridges can measure towball mass directly, but most cannot. An alternative method:
1. Weigh the trailer by itself (all trailer wheels on the platform, unhitched) — this gives you the trailer's total weight
2. Weigh the vehicle by itself (without trailer) — this gives you the vehicle's actual weight
3. Hitch the trailer and weigh the vehicle again — the difference between this reading and the vehicle-only reading is approximately the towball mass (the weight transferred from the trailer to the vehicle)
Not all weighbridges can accommodate this process. If you need a precise towball mass measurement, a dedicated towball scale or a weighbridge with the right configuration is required.
**Why it matters:** Towball mass counts against your vehicle's GVM, payload and rear axle rating. It also affects towing stability — too little towball mass can cause trailer sway; too much can overload the rear axle.
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How to Interpret the Numbers
Once you have your weighbridge readings, compare each figure against the relevant limit from your vehicle and caravan compliance plates:
**Vehicle limits (from the compliance plate or owner's manual):**
**Caravan limits (from the caravan compliance plate):**
All limits must be satisfied simultaneously. Exceeding any one of them means the setup is non-compliant — regardless of whether the others have headroom.
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When to Seek Professional Advice
A weighbridge ticket gives you actual numbers, but interpreting those numbers in the context of your specific vehicle, caravan and setup can be complex. Consider seeking professional advice if:
- Your weighbridge reading is close to or over any limit and you are unsure what to adjust
- Your rear axle load is near its rating and you need to understand the interaction between accessories, cargo and towball mass
- You are planning modifications (canopy, GVM upgrade, suspension) and want to understand the weight implications before committing
- You are buying a vehicle or caravan and want to confirm the combination will work before purchase
- You need engineering certification for a modification and want to understand the weight position first
A weighbridge reading is the starting point. Understanding what it means for your specific setup — and what to do if a limit is exceeded — may require professional input.
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Practical Tips for a Weighbridge Visit
- Call ahead to confirm the weighbridge is operational and can provide axle weights
- Ask about cost — public weighbridges typically charge a modest fee
- Weigh the vehicle fully loaded — fuel, water, passengers, gear and accessories — as it would be for a trip
- If possible, weigh the vehicle alone first, then the combination, to calculate towball mass
- Record all readings — take a photo of the ticket or write down each figure
- If the weighbridge operator is experienced, they may be able to guide you through the process
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