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.
Matching is a system problem
A tow match is not a comparison between caravan ATM and advertised towing capacity. It is an assessment of a loaded vehicle, a loaded caravan and the forces connecting them.
ClearPath uses an evidence-first method designed to answer a more useful question: which limit is likely to control this specific combination in its intended travelling condition, and what remains unknown?
The method does not turn incomplete inputs into certainty. When a decisive value is missing, the correct output is a verification requirement—not an invented specification or an unconditional verdict.
The five layers of a ClearPath review
1. Identity confidence
The first task is to identify the exact vehicle and caravan.
For the vehicle, year, series, variant, body style, engine, drivetrain and transmission can affect ratings. For the caravan, model year, layout, axle configuration and fitted options can change tare, ATM and ball mass.
A near match is not automatically a valid match. ClearPath records ambiguity and asks for the plate, handbook or other primary evidence when necessary.
2. Source confidence
Each important figure is considered in context:
These sources are not treated as equivalent. Published ratings, measured values and calculated estimates are labelled separately.
3. Vehicle load model
ClearPath builds the proposed loaded vehicle from:
This produces an initial GVM and payload view. Load position is then considered because the rear axle may become the controlling limit before GVM.
Read the hidden weight cost of touring accessories and vehicle setup planning before modifications.
4. Caravan load model
The caravan assessment distinguishes between:
A calculated payload allowance—ATM minus tare—is not a guarantee that every kilogram can be placed anywhere. Axle, tyre, coupling and stability requirements still apply.
Use caravan towing setup: common compliance risks for the underlying concepts.
5. Combination constraints
The proposed travelling setup is checked against each applicable limit:
The tightest remaining margin is the controlling constraint. A combination that passes one limit can still fail another.
Why advertised towing capacity is only a gate
Towing capacity answers whether the trailer is above a nominated maximum under the manufacturer's conditions. It does not reveal how much vehicle payload remains after coupling load, whether the rear axle is overloaded or whether GCM allows both the vehicle and trailer to operate near their individual maxima.
Consider a hypothetical combination:
The trailer may be below the headline towing capacity, yet the vehicle would already have a payload problem before considering axle effects. The controlling issue is not towing capacity.
This example is illustrative only. A real assessment must use the exact vehicle, caravan and measurements.
Confidence states, not false precision
ClearPath separates outcomes into practical confidence states.
Verified enough to calculate
The exact variants are identified and the necessary ratings come from appropriate sources. The calculation can be reproduced, though a future change in load may require rechecking.
Indicative—measurement required
Some values are reliable enough for planning, but actual loaded masses or axle distribution remain unknown. The next step is a defined weighbridge measurement.
Specification conflict
Sources disagree or the plate does not match the generic specification. No definitive result should be issued until the conflict is resolved.
Insufficient evidence
A decisive value—such as GCM, rear axle rating or actual caravan identity—is missing. The useful result is a list of evidence to obtain.
This approach is more honest than displaying a precise-looking score built on weak inputs.
The controlling-limit worksheet
For every proposed match, create a simple table with four columns:
Complete a row for GVM, each axle, towing capacity, coupling load, ATM, GTM and GCM. Mark every operating value as published, measured, calculated or estimated.
The smallest positive margin deserves attention. Any negative margin is a stop signal until the loading plan, vehicle, caravan or approved ratings change. Any blank decisive row means the assessment is incomplete.
Modifications and upgraded ratings
A modification can change mass, load distribution and sometimes an approved rating. Those are separate effects.
A suspension kit adds weight and can alter ride height. It does not automatically increase GVM, axle ratings, towing capacity or GCM. Where an approved upgrade changes a rating, ClearPath relies on the documentation for that specific vehicle and notes any operating conditions.
For context, see what GVM upgrades do and do not do and pre-registration versus post-registration upgrades.
What a good weighbridge plan measures
One number for the complete combination is rarely enough. The plan should provide the measurements needed to derive or confirm:
Record passengers, cargo, fuel, water and weight-distribution equipment for each measurement. Without the loading condition, a ticket is difficult to reuse or compare.
Read why weighbridge results matter.
Decision rules before purchase
Before committing to a vehicle or caravan:
1. Reject generic identity matches when ratings differ by variant.
2. Require evidence for every controlling rating.
3. Model the complete accessory and passenger load.
4. Use a realistic caravan travel mass, not tare alone.
5. Check rear axle and GCM, not only GVM and towing capacity.
6. Preserve a practical margin for changing cargo and imperfect estimates.
7. Convert the plan into actual measurements before relying on it for travel.
If you are comparing vehicles, use what to check before buying a tow vehicle. If the vehicle and caravan are already shortlisted, start a Tow Match Check.
About the methodology
The ClearPath Technical Team maintains this method as part of ClearPath's broader evidence and review framework. Database values are published only when their source and verification status meet the required threshold; unknown values remain unknown. Calculations are disclosed, and material assumptions are presented to the user.
Learn more about the people, editorial controls and verification approach on the About ClearPath and ClearPath page.