Is your motorhome overloaded?

Motorhome and large campervan loading is simpler than a tow setup — there's no ball weight or hitch to worry about — but overloading is just as dangerous. The two numbers that matter most are your total loaded weight (GVM) and how much weight is on the rear axle.

Your motorhome details

Loading check

How to check your motorhome or campervan loading

Motorhomes and campervans pick up weight quietly. A full water tank is 100 kg. Two 9 kg gas bottles are 18 kg. A modest lithium house battery setup adds 50–80 kg. Add bikes, an awning, food, clothes, books, the inevitable extra pair of boots, and you can be 300 kg over your kerb weight without putting anything obviously heavy in the rig. Touring Brain's loading check tells you whether all of that still leaves you under your motorhome's Gross Vehicle Mass (GVM).

Enter your motorhome's GVM (the ceiling, stamped on the compliance plate), the kerb weight (or "tare," what the rig weighs empty as it left the factory), then everything you carry: water and waste tanks, gas, batteries, food and gear, plus the people who'll be on board. The calculator subtracts your loaded total from GVM and tells you how much headroom you have — or how much over you are. If you're over, it'll show which line items are the biggest contributors so you know where to trim.

Real-world numbers always beat estimated ones. New Zealand has weighbridges in most large towns and at many transport depots — typical fee is $20–$40 to weigh in. For an accurate front and rear axle split (which matters for tyre pressures and handling), ask for individual axle weighing.

Frequently asked questions about motorhome GVM

What is GVM and where do I find it?

GVM (Gross Vehicle Mass) is the maximum legal loaded weight of the motorhome, including everything and everyone in it. It's stamped on the compliance plate, usually in the cab door jamb or under the bonnet. Don't confuse it with kerb weight (empty) or your driver licence's weight ceiling.

What's a "weighbridge" and how do I use one?

A weighbridge is a calibrated platform that weighs your loaded vehicle. Most NZ transport depots, council yards and some service stations have one. Drive on, the operator weighs you, you pay a small fee. For a useful check, weigh fully loaded the way you'd actually travel — water tanks topped up, gas full, gear stowed, people on board.

What should I include when calculating loaded weight?

Everything not in the kerb weight. That's: water (fresh, grey and black tanks), gas bottles, leisure batteries, all your gear, food, water and pet supplies, bikes, kayaks, generator, fuel beyond what kerb weight assumed, and every person who'll be in the rig when it's moving. Even small things add up — a typical campervan has 100–200 kg of "stuff" you didn't think about.

What weight do water and gas add?

Water is 1 kg per litre. A 100-litre fresh water tank full is 100 kg. A 9 kg LPG bottle is around 18 kg full (bottle plus contents). A 4.5 kg bottle is around 12 kg full. Two full 9 kg gas bottles plus a full water tank is 136 kg of payload before you put anything else in.

Does a motorhome need a Certificate of Fitness?

If your motorhome's GVM is 3,500 kg or less it needs a Warrant of Fitness, like a car. Above 3,500 kg GVM it needs a CoF (Certificate of Fitness), which is more rigorous and required every six months. Many NZ self-built and imported motorhomes sit just above the 3,500 kg threshold, so it pays to know which side you're on.

More tools for New Zealand touring

• Towing calculator — for caravans, fifth-wheelers and tow setups.
• Tyre safety check — DOT code age and load-based pressures.
• Pre-departure checklist — nothing forgotten before you hit the road.
• Plan a route — Loop, A→B with stops, or destination-mode trip planning.
• 3-day weather briefing — wind, rain and gust forecasts.
• Find NZ campsites & holiday parks — DOC and OSM data on a map.