The free weights cheat sheet

Caravan Towing Weights Cheat Sheet

Weights are the bit nobody wants to talk about at the caravan show. We do, because getting them wrong is how good trips go bad. This is the cheat sheet from our videos: what each number means, the five checks, and where to find your figures.

Check my car and van

The numbers, in plain English

Tare: What the van weighs empty, with no water, gas or gear. Ask whether it includes the options fitted to your van.
ATM (Aggregate Trailer Mass): The most the van is allowed to weigh fully loaded, set by the manufacturer. It includes the weight sitting on your towball.
GTM (Gross Trailer Mass): The most the van's axles can carry when it's hitched up. It's the loaded van minus what's sitting on the towball.
Payload: ATM minus tare. Water, gas, food, gear and anything bolted on after the factory all come out of this number.
Ball weight: The downward push of the loaded van's drawbar on your towball. It changes with how and where you load the van.
Braked towing capacity: The most your car's maker says it can tow when the van has its own brakes. It's a ceiling, not a target.
Towball download limit: The most weight allowed on the towball. Your car, towbar and towball each have a rating, and the lowest one is your limit.
GVM (Gross Vehicle Mass): The most your car can weigh loaded: people, fuel, accessories, gear and the ball weight on the back.
GCM (Gross Combination Mass): The most your car and van can weigh together, both loaded. Plenty of rigs pass every other check and fail this one.

The 5 checks before you buy a van

Pop your own numbers in. Every line needs to pass, not just the towing capacity. If one says check again, that's your cue to sort it before you sign anything.

1. The van ATM is at or below the car's braked towing capacity.
Needs numbers
Enter the van ATM and the car's braked towing capacity
2. The loaded ball weight is at or below the car's towball limit.
Needs numbers
Enter the loaded ball weight and the towball limit
3. The car's loaded weight plus ball weight is at or below GVM.
Needs numbers
Enter the loaded car weight, ball weight and GVM
4. The car plus van is at or below GCM.
Needs numbers
Enter the loaded car weight, van ATM and GCM
5. The van payload covers water, gas and gear.
Needs numbers
Enter the van ATM, tare and what you'll carry

Your numbers stay on your phone. Nothing is saved or sent to us.

Where to find your numbers

Your vehicle's owner's manual for braked towing capacity, towball limit, GVM and GCM.
The compliance plate on the car and on the van, for ATM, tare and GVM.
The manufacturer's spec sheet for anything the plate and manual don't cover.

Get it weighed

Every van comes with its weighbridge docket, so you know its real weight, not a brochure guess. Load up the car and van like you're heading off, then run the whole rig over a public weighbridge. It's the only way to know what you're really towing.

General information only. Always check your vehicle and caravan manufacturers' specifications and your state's rules.

Towing overweight? Here's what happens

Watch on YouTube (opens in a new tab)

Steve walks through what goes wrong when a rig is over its limits.

Send us your car and we'll check it against our vans

Tell us what you drive. We'll do the sums against the vans on our yard and give you a ring.