On average 7 people are killed and 45 seriously injured in accidents involving light trailers each year so having your trailer right is very important to keep you and other road users safe. While you may not be fined for towing a trailer between 750kg and 2000kg without brakes, if your vehicle unbraked tow rating is less that the weight of the trailer then you could be fined for unsafe loading.

All vehicle towbars are rated to a certain weight. If it is only certified or recommended that the tow vehicle is rated to 750kg GVM unbraked (check your vehicles handbook for specs) then it is unwise to tow an unbraked trailer exceeding 750kg GVM. Just remember that you could be charged with dangerous driving if you are caught or have an accident, incurring serious penalties as well as possibly voiding your insurance.

If you are unable to determine the towing capacity of your tow vehicle, either check with your local towbar manufacturer, go online and check your vehicles specifications, or as a rough guide set out by the NZ Transport Authority use the following – “the laden weight of an unbraked trailer should not exceed three quarters of the unladen weight of the towing vehicle and then only if the towing vehicle's brakes and tyres are in excellent condition. A trailer heavier than this may prevent the vehicle combination from meeting the seven metre for 30km/hr brake performance requirement.”

When deciding what brakes you need on your trailer you need to look at the “Guide to safe loading and towing for light vehicles” and the Land Transport rule “Light-vehicle Brakes 2002” and its amendments.
The weight ratings below have various specifications and requirements for the amount of braking they require and what the braking systems must be able to do.

Up to 2000kg GVM

For up to 2000kg load capacity or GVM (Gross Vehicle Mass which is the weight of the trailer and its load combined, brakes are not legally required. NZ law states that the tow vehicle and trailer must be able to safely stop safely within 7 metres from a speed of 30km/hr.

A single rated safety chain must be fitted and attached between the two vehicle and trailer when towing.

2000 to 2500kg GVM

Between 2000kg and 2500kg GVM trailers must be braked on at least one axle with either override brakes or with cab controlled brakes and again must be able to stop within 7 metres from 30km/hr.

There are three kinds of braking systems which can be used for trailers in this weight class:
- Mechanical override brakes, with either disc or drum brakes
- Hydraulic override brakes, with either disc or drum brakes
- Electric brakes, which are used with drum brakes. Electric braking systems are used in conjunction with a trailer mount controller. These are available with either fixed or proportional outputs, depending on what you require for your trailer.

Dual crossed safety chains or an electrically operated breakaway system is also required on trailers in this weight class. Both coupling and chains are required to be rated and marked.

Over 2500kg GVM

Trailers with a GVM over 2500kg up to 3500kg must be fitted with brakes with in-cab control. A breakaway system must also be fitted and a mechanical park brake on at least one axle which can hold the trailer and load in position on a slope of 1 in 5 (approx. 20 degrees). A mechanical park brake operates independently of the main braking system, and is intended for use if the main braking system fails or is compromised. It must act on both wheels of at least one axle and must be capable of stopping the trailer within a distance of 18 metres from a speed of 30km/h.

The stopping within 7 metres at 30km/hr rule still applies.

Safety chains are not required and generally would stop the breakaway system from operating.

Over 3500kg GVM

Over 3500kg GVM falls into the realm of Heavy Transport regulations and the rules and regulations around braking in this weight class are very stringent. Certification is required on almost every aspect of the trailer and requires professional engineering input at every stage of the manufacturing process.

What is a breakaway system?

Breakaway systems are a backup emergency braking system fitted to a trailer which ensure that if a trailer is unintentionally disconnected from its towing vehicle, the trailer brakes will automatically and immediately apply and will remain applied for at least 15 minutes.

In-cab Control

When using in-cab controlled brakes, the driver of the tow vehicle must be able to adjust the braking gains settings from the driving position. They must also be able to apply the emergency brake if required. The crucial element is that the brakes, when applied, must operate as a direct result of the driver’s action.

There are two kinds of in-cab controlled braking systems available in New Zealand. These are:

• Hard wired
• Wireless control. Trailers are wired with braking modules. Once the trailer is connected for use, braking can be operated by a hand piece in the tow vehicle. The beauty of a wireless braking system is that the handset can easily be transferred between vehicles, as it just plugs into a standard vehicle power socket, meaning it can be used with among multiple vehicles. Wireless braking systems also allow for pre-set braking levels to be set according to the load being carried. This is coupled with sensitivity adjustment settings, which control how quickly the pre-set braking levels are applied to a trailer.

The team at Trailequip will be happy to answer any questions you may have regarding what braking systems are the best options for you to consider, so if you need advice, then feel free to give us a call or simply flick us an email.