Frequently asked questions

What are the 8 main weight limits to comply with when towing to be legal?

 

Tow Capacity – the maximum weight your vehicle can tow. There are two weight limits. An unbraked and a braked limit.

TBM (Tow Ball Mass) – this is the maximum weight on the tow ball from the tow coupling. Limit is set by either the tow vehicle, the towbar or the towbar tongues manufacturer. TBM is also affected by how level your trailer is when connected to the tow vehicle.

Front Axle Weight – Affected by accessories eg bull bars, light, suspension upgrades etc.

 When towing, weight is reduced on the front axle. For every 100kgs of TBM approximately 50kgs is transferred from the front axle to the rear axle.

Rear Axle Weight - Often overlooked and easily exceeded. Due to the laws of physics the load from the TBM is roughly multiplied by 1.5. For every 100kg of TBM approximately 150kgs is added to the rear axle.

GVM (Gross Vehicle Mass) – the maximum your tow vehicle can weigh. This includes your TBM.

GTM (Gross Trailer Mass) – The maximum weigh of your caravan/trailer on its wheels only.

ATM (Aggregate Trailer Mass) - The maximum the trailer can weigh. The GTM plus TBM.

GCM (Gross Combination Mass) – The maximum total weight of both vehicles. GVM plus GTM

 

Why is proper weight distribution important for people with caravans, motorhomes, or even race cars here in NZ?

Weight distribution is often overlooked when it comes to caravans, tow vehicles, motorhomes, and light commercial vehicles. People often think only about GVM, maximum trailer weight, and tow ball weight for legal compliance, however there are up to eight different weights to consider when towing a caravan or trailer. Front and rear axle weights, in particular, are frequently overlooked and very often exceeded. You cannot check all your individual axle weights on a solid weighbridge; this is where a professional weigh using individual weigh pads becomes essential.

Why should I be weight compliant?

In New Zealand, NZTA States in Factsheet 13 - Vehicle Dimensions and Mass

 “You must not exceed the vehicle ratings specified by the vehicle manufacturer for the chassis, axles, tyres and other components of the vehicle. For example, you are not allowed to load your vehicle above the specified maximum gross vehicle mass (GVM), gross combination mass (GCM)”

Just because it is not policed to the same extent as in Australia, does not mean we don’t need to comply to these limits.

In the event of an accident the police may choose to weigh your vehicles. If you are found to be exceeding your manufacturers weight limits you may be charged with an infringement notice (fine).

This then gives your insurance company an opportunity to decline any claims.

What kind of scary situations can happen if a caravan or vehicle isn't properly balanced?
You might experience a feeling of light, vague steering, or the dreaded sway that can occur when going down hills, in strong winds, or from a passing truck. Once a caravan starts to sway, it can often lead to an accident.

What are the disadvantages of using a platform weighbridge vs a professional weigh with individual wheel pads?

A 'platform' weighbridge only allows you to weigh complete vehicles, It can be near impossible to get all your individual axle & wheel weight so you cannot work out exactly how your vehicles weight is distributed between left & right wheels, axles front to back etc. You will also need to work out your own weight calculations.

By being professionally weighed by us, using our individual wheel pads, you can see your wheel weights in real time on the wheel pads digital displays. As we weigh individual wheels, we are able to provide a full report on all your vehicles weights and where that weight is distributed, left vs right, front vs back, axle by axle. By using our specific tow ball scale, you will get a true tow ball weight at your towing height. All the calculations are done for you in a documented take home comprehensive report.

Can I get a GVM upgrade for my vehicle if I am exceeding my manufacturers weigh limits?

In some cases the answer is yes, however not all vehicles can have a GVM upgrade.

The ones that do, you will need to have certified by a Low Volume Vehicle Certifier. Contact your local Low Volume Vehicle Certifier before doing any suspension upgrades. Generally, you will need to fit an approved GVM suspension upgrade kit. Some kit manufactures are Pedders, Ironman, Outback Armour etc.

Just remember a GVM upgrade does not increases your GCM.

Why is it important to have your trailer level?

The more level your caravan or trailer sits when towing, the more stable it will be under tow. Our detailed weighing helps you achieve optimal balance, improving your towing experience and safety on New Zealand roads.

You might see a tandem axle caravan with its drawbar facing the ground and the back pointing skywards; this can overload the caravan's front axle, causing sway. Conversely, a drawbar on a tandem axle trailer pointing up with the back of the caravan pointing down can overload the tow ball weight, the tow vehicle and caravan's rear axle, therefore lightening the front axles, leading to a vague steering feeling and sway.

" Vehicle Weight Check NZ expertise in weight distribution, ensures caravan and tow vehicle's weights are safe and compliant for New Zealand adventures."

Ensuring your safety and compliance

Don't leave your safety to chance. Let Vehicle Weight Check NZ provide you with the accurate measurements and expert advice you need to travel confidently. We are committed to helping you understand and achieve optimal weight distribution for all your vehicles.