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
Choosing a tow vehicle to match a caravan — or choosing a caravan to match a tow vehicle — is one of the most consequential decisions an Australian touring owner makes. It is also one of the most commonly misunderstood.
The temptation is to check the vehicle's towing capacity against the caravan's ATM and call it a match. But that is only one of four checks that matter, and it is often the least binding one. The other three — payload, GCM and axle load ratings — tell a different story for most real-world setups.
This guide walks through the practical approach to matching a vehicle and caravan, using worked examples and safety caveats.
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The Four Checks That Matter
When matching a tow vehicle and caravan, there are four separate checks:
1. **Tow rating check** — compare the actual loaded trailer mass with the applicable towing ratings and manufacturer conditions.
2. **Payload check** — the vehicle must have enough payload for accessories, passengers, fuel, water, cargo and tow ball mass.
3. **GCM check** — compare actual combined mass with GCM, counting coupling load once.
4. **Axle load check** — compare total actual front and rear vehicle axle masses with their respective ratings. Check actual trailer axle mass separately against GTM and trailer axle limits.
Why the Tow Rating Is Not Enough
The tow rating tells you the maximum trailer ATM the vehicle is rated to tow. It says nothing about:
For many vehicle and caravan combinations, the tow rating is sufficient but the axle load check fails. This is why axle load ratings — not tow ratings — are often the binding constraint.
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Worked Example: Toyota LandCruiser 300 GXL and Jayco Expanda
Vehicle specifications (illustrative)
Caravan specifications (illustrative)
Check 1: Tow Rating
Vehicle tow rating (3,500kg) ≥ caravan ATM (2,200kg). **Pass.**
Check 2: Payload
Vehicle payload: 935kg. Deductions:
| Item | Weight (kg) |
|---|---|
| Passengers and personal items | 180 |
| Fuel and water tanks | 90 |
| Accessories (bullbar, canopy, drawers, roof rack, towbar) | 148 |
| Cargo and gear | 50 |
| Tow ball mass (fictional separately measured load) | 264 |
| **Total deductions** | **732** |
Remaining payload: 935 - 732 = 203kg. **Pass** — but with tight headroom.
Check 3: GCM
Vehicle mass before coupling: 2,415 + 468 (accessories + fuel/water + passengers + cargo) = 2,883 kg. With a hypothetical 264 kg download the vehicle is 3,147 kg. For a fictional 2,100 kg total loaded caravan, trailer axle mass is 1,836 kg. Combined mass = 3,147 + 1,836 = 4,983 kg, or 2,883 + 2,100 = 4,983 kg. Against a 6,900 kg GCM rating, the arithmetic margin is 1,917 kg. The download is counted once.
Check 4: Axle Load
No rear axle result can be derived from total vehicle mass or accessory categories alone. For a separate fictional geometry example, use a measured unhitched rear axle mass of 1,550 kg, wheelbase 3,000 mm, rear-axle-to-towball distance 1,200 mm and measured download 264 kg. Rear change = 264 × (1 + 1,200 / 3,000) = 369.6 kg; front change = −105.6 kg. Rear total = 1,919.6 kg, which exceeds a fictional 1,860 kg rating by 59.6 kg.
These extra axle measurements and distances are required inputs; they are not inferred from the preceding mass tally. An active weight-distribution hitch needs measured coupled axle checks or a separate validated force model.
Use the detailed weight-distribution calculator with actual measurements. A rating comparison is conditional on correct inputs and does not establish stability.
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The Practical Approach to Matching
If You Have a Caravan and Are Choosing a Vehicle
1. **Find the caravan's ATM and GTM.** These are on the compliance plate.
2. **Measure loaded towball download** for the intended loading condition.
3. **List the accessories you plan to fit** and their weights.
4. **List passengers, fuel, water and cargo** you expect to carry.
5. **Calculate the required payload:** accessories + fuel + water + passengers + cargo + tow ball mass.
6. **Check each candidate vehicle:**
- Actual loaded trailer mass within applicable vehicle/equipment limits and manufacturer conditions
- Payload ≥ required payload
- GCM rating ≥ actual coupled vehicle axle masses + actual trailer axle masses
- Each vehicle axle rating ≥ its actual total axle mass; check trailer GTM separately
Use Compare Vehicles to compare these checks across multiple vehicles at once.
If You Have a Vehicle and Are Choosing a Caravan
1. **Find the vehicle's tow rating, payload, GCM and axle ratings.** These are on the compliance plate.
2. **Calculate available payload** after accessories, fuel, water, passengers and cargo.
3. **The maximum caravan ATM** that your vehicle can tow is the lowest of:
- The vehicle's tow rating
- The caravan ATM that leaves enough payload for tow ball mass
- A caravan whose coupling load and the resulting total vehicle axle masses remain within all applicable limits
4. **Choose a caravan with ATM within that limit.**
Use Tow Match to check a specific vehicle and caravan combination.
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Common Mismatches
Heavy Caravan, Light Vehicle
A vehicle with tow rating of 2,800kg towing a caravan with ATM of 2,700kg. The tow rating check passes — but a hypothetical 324 kg towball load may cause the total rear axle mass to exceed its rating, and the vehicle may not have payload for accessories and tow ball mass combined.
Heavy Accessories, Adequate Tow Rating
A vehicle with tow rating of 3,500kg and payload of 778kg. The owner fits 200kg of accessories (bullbar, drawers, canopy, roof rack, dual battery). Remaining payload: 578kg. Add passengers (180kg), fuel and water (90kg), cargo (50kg) and tow ball mass (264kg). Total: 584kg. The vehicle is 6kg over payload — even though the tow rating is sufficient.
Front Axle Exceeded by Bullbar
A vehicle with front axle rating of 1,650kg. A heavy bullbar (25kg) plus winch and dual battery at the front loads the front axle. If the loaded vehicle weight puts 1,680kg on the front axle, the vehicle is outside its axle load rating — even though it is within GVM and the tow rating is sufficient.
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Sources and Review Method
The matching methodology in this guide follows:
ClearPath's Tow Match compares supplied specifications and labelled mass scenarios. Axle assessment remains incomplete without actual coupled axle measurements. Confirm exact ratings and actual loads independently.
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What Next
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