...

Curious or confused?

Adequate knowledge of trailers is necessary for responsible ownership. The information provided here will introduce you to common technical terms, relevant NZTA regulations, and basic operational guidelines. To learn more, visit NZTA online or any other relevant sources.

Technical Definitions
Light Trailers

Light trailers are vehicles without motive power (i.e. they do not have the ability to propel themselves) and have a maximum gross vehicle mass (GVM) or gross laden weight (GLW) of 3500kg or less. Light trailers includes class TA trailers (GVM < 750kg) and class TB (750kg ≤ GVM < 3500kg).

Service & Parking Brakes

Trailer service brakes engage, and often regulate, the trailer’s brake effort in conjunction with, or in relation to, the towing vehicle’s brake application, and assists the towing vehicle to slow down and stop.

A trailer parking brake holds an already immobile trailer and is capable of remaining applied for an indefinite period without further attention. Unlike service brakes, parking brakes are not used in conjunction with the towing vehicle to slow down and stop.

Disc Brakes

Trailer mounted disc brakes consist of an exposed, disc-shaped rotor and an edge mounted caliper. The caliper compresses brake pads against the rotor, which is, in turn, reduces the wheel’s rotational speed. It offers a simplistic, low maintenance trailer braking option that is mechanically or hydraulically operated. They are suitable for all braking applications and can be submerged in the water safely.

Mechanical disk brakes: Hydraulic disk brakes:
Cheaper than hydraulic disk brakes. Greater reliability than mechanical disk brakes.
Less responsive than hydraulic disk brakes. Equalizes brake power between all brakes.
Cable operated, and therefore require frequent cable tension adjustments. No frequent adjustments are required.
Drum Brakes

Drum brakes house its major components inside a large metal drum that rotates along with the wheel. By means of a hydraulic or electrical mechanism, brake pads are pressed outwards against the inside of the drum, reducing rotational speed. This brake type offers an economical and effective braking solution, whilst also providing smooth, damped braking that is ideal for fragile goods or animal transportation.

Hydraulic drum brakes: Electric drum brakes:
Offer smooth, damped braking action. Effective and efficient braking option.
Requires no electrical connection with the towing vehicle. Offers adjustable brake power by means of a trailer-mounted or in-cab brake controller.
Greater reliability than electric drum brakes. Easily mated to a break-away brake system.
Not as efficient as disk brakes. Used in both direct and indirect braking systems.
Built-in, independent, mechanical parking brakes are available.
Indirect Braking Systems

Indirect braking systems, or indirect service brakes, operate without direct input from the driver of the tow vehicle. They can be either inertia-activated or electric (brake-light activated), and both disc brakes and drum brakes can be used in this system. If electrically activated brakes are used, a trailer-mounted brake controller is needed to adjust the braking force. Indirect braking systems are the most commonly used braking systems on trailers rated GLW (Gross Laden Weight) ≤ 2500kg, and cannot by law be used on trailers rated between 2501kg ≤ GLW ≤ 3500kg.

Inertia-activated systems:

Pros: Cons:
No dedicated towing vehicle required. Braking not operable in reverse.
Inexpensive and reliable. Deactivation of brakes required before reversing.
Low maintenance.

Electric (brake-light activated) systems:

Pros: Cons:
No dedicated towing vehicle required. Braking not as advanced as direct electric brake systems.
Braking operable in reverse. Higher maintenance drum brakes are used.
Includes mechanical parking brake.
Direct Braking Systems

Direct braking systems, or direct service brakes, operate as a direct result of braking input from the driver of the tow vehicle. They are load–adjustable and incorporate an emergency over-ride function mounted near the driver’s seat, which operates the trailer brakes independently of the tow vehicle. Brake types used for direct systems are hydraulic disc and electric drum brakes. Trailers rated between 2501kg ≤ GLW (Gross Laden Weight) ≤ 3500kg are required by law to employ direct braking systems.

Electric-hydraulic systems:

Pros: Cons:
Can allow for no dedicated towing vehicle. An additional mechanical parking brake is required.
Allows the use of hydraulic disk brakes. Unfamiliar brake system in New Zealand.
Includes break-away brake system. Pending NZTA assessment and approval.
Braking operable in reverse.

Electric systems:

Pros: Cons:
Provides accurate, proportional brake control. Dedicated towing vehicle is required.
Includes built-in mechanical parking brake. Higher maintenance drum brakes are used.
Easily mated with a break-away brake system. New Zealand tried and tested brake system.
Braking operable in reverse.
Break-away Brake Systems

A break-away brake system is a service or parking brake fitted to a trailer that ensures, under all conditions of use, that if the trailer is unintentionally disconnected from its towing vehicle, the brakes will immediately engage in order to bring the trailer to a halt. The action time of the break-away brake must be a minimum of 15 minutes.

Non-equalizing & Equalizing Suspension

A trailer that utilizes two or more axles, mounted independently of each other, cannot equally distribute the trailer weight between the axles when traversing uneven terrain, or when the towing vehicle’s tow ball and trailer coupling are not at the same height. Such a suspension system is classed as a non-equalizing suspension system. Although an economical option, periodic point loading can cause bearing and suspension failure, and result in poor towing characteristics.

Equalizing suspension systems consist of multiple axles with a rocker arm between each axle. This enables the axles to have greater, independent vertical travel whilst maintaining full weight carrying capacity at any point and effectively distributes the weight between all axles. Axle overloading is mitigated, prolonging axle, hub and bearing service life, and towing characteristics are improved.

NZTA Brake Regulations
Introduction

The New Zealand Transport Agency (NZTA) introduced a new regulation, the Land Transport Rule: Light-vehicle Brakes 2002 (Rule 32014), on 1 April 2002. This rule sets the safety requirements and standards of brake systems installed on all Light Vehicles and Light Trailers, new and existing, with a Gross Laden Weight (GLW) of up to 3500kg. The Gross Laden Weight refers to the maximum combined weight of the trailer and payload. A summary of the brake requirements with respect to the Light Trailer GLW categories not exceeding 3500kg is given below.

Trailer GLW: 0kg - 2000kg

Trailers with a Gross Laden Weight of GLW < 2000kg do not require service nor parking brakes. However, if brakes are fitted, then the following requirements apply:

  • Both wheels of at least one axle must be braked;
  • It must be fitted with a safety chain (compliant with ADR62 Determination of 1995), connected between the towing vehicle and the trailer.
  • The load must not be transferred to an un-braked axle during braking; and
  • Combined with the towing vehicle’s service brakes, must be capable of stopping the combination of towing vehicle and trailer within a distance of 7 meters from a speed of 30km/hr.

It is critical to consider the towing capacity of the towing vehicle when towing a non-braked trailer.

Trailer GLW: 2001kg – 2500kg

Trailers with a Gross Laden Weight of 2001kg ≤ GLW ≤ 2500kg must be fitted with service brakes, but a parking brake is not required. The service brakes may be either indirect braking or direct braking systems and must meet the following requirements:

  • Both wheels of at least one axle must be braked;
  • The load must not be transferred to an un-braked axle during braking;
  • Combined with the towing vehicle’s service brakes, must be capable of stopping the combination of towing vehicle and trailer within a distance of 7 meters from a speed of 30km/hr; and
  • The coupling system must show the manufacturer’s load rating corresponds with the GLW the trailer. It must also be fitted with either two (2) crossed safety chains (compliant with ADR62 Determination of 1995), mechanical connections between the towing vehicle and the trailer, or an emergency breakaway brake.
Trailer GLW: 2501kg – 3500kg

Trailers with a Gross Laden Weight of 2501kg ≤ GLW ≤ 3500kg must be fitted with direct service brakes, a break-away brake system, and an independent mechanical parking brake. Safety chains are not required because the emergency break-away brake system is installed.

The service brakes must be a direct braking system, and must meet the following requirements:

  • Must be fitted with an in-cab brake controller; and
  • Combined with the towing vehicle’s service brakes, must be capable of stopping the combination of towing vehicle and trailer within a distance of 7 meters from a speed of 30km/hr.

The parking brake must be a mechanical brake, independent of the service brake, and meet the following requirements:

  • Both wheels of at least one axle must be braked;
  • Must be capable of stopping the trailer within a distance of 18 meters from a speed of 30km/hr, or alternatively, be capable of holding the trailer at rest on a slope of 1 in 5.
NZTA Dimension Limits
Light Trailers: Maximum Length

The maximum overall length for a light trailer (including drawbar and load) is 12.5 meters. The maximum overall length for a rigid tow vehicle and light trailer combination (including load, but excluding collapsible mirrors) is 22 meters.

The maximum rear overhang for light trailers is 4 meters and is measured from the halfway point between two axles, or the 2nd axle in a tri-axle set, to the rear of the trailer or its load, whichever is greater.

For light trailers, the front overhang is the distance from the center of the tow coupling, to the foremost point of the vehicle (including its load). The maximum is 2.04 meters radius arc ahead of the tow coupling.

The inter-vehicle spacing is the distance between the towing vehicle (excluding the tow coupling shroud) and the trailer (excluding the drawbar but including the load). The maximum for light trailers is 4 meters, and there is no minimum spacing. The trailer (or its load) may overhang the towing vehicle.

Light Trailers: Maximum Width

The maximum width for a light trailer (including its load) is 2.55 meters (excluding side marker lights and direction indicators and the bulge towards the bottom of the tires).

Loads that overhang the outside of the body or deck of the vehicle by more than 1m to the front or rear, or more than 200 millimeters to the left or right side, need to carry special warning devices attached to the overhanging end(s) of the load. The total width of a loaded light trailer is therefore 2.95 meters. Visit www.nzta.govt.nz for more information on the aforementioned special warning devices.

Light Trailers: Maximum Allowable Height

The maximum allowable height (including the load) is 4.3 meters. All vehicles must be loaded in a safe manner, with a height appropriate for the type of load.

Trailer Operational Guidelines
Safe Trailer Towing

Both light and heavy vehicles towing a trailer are limited to a maximum open-road speed of 90km/h. School buses towing a trailer are limited to the maximum open road speed of 80km/h. Drivers also need to obey any lower speed limits that apply on particular roads.

If you tow a light trailer, you need to be aware that the trailer can impose a large weight on the rear of your tow vehicle. This weight can, by lever action through the chassis of the vehicle, reduce the effective mass bearing on the front axle(s) of your vehicle. It is important, therefore, that you load your trailer carefully so the load is distributed centrally over the axle(s) of the trailer. This will allow your vehicle to maintain the front-wheel grip on the road, so you can continue to steer it safely.

Note: Look in your vehicle manual for the maximum weight your vehicle can tow. In addition, there needs to be a downward force, approximately 10% of the weight of the trailer and its load, on the tow coupling of a simple trailer for stable towing.

The maximum rear overhang for light trailers is 4 meters and is measured from the halfway point between two axles, or the 2nd axle in a tri-axle set, to the rear of the trailer or its load, whichever is greater.

For light trailers, the front overhang is the distance from the center of the tow coupling, to the foremost point of the vehicle (including its load). The maximum is 2.04 meters radius arc ahead of the tow coupling.

The inter-vehicle spacing is the distance between the towing vehicle (excluding the tow coupling shroud) and the trailer (excluding the drawbar but including the load). The maximum for light trailers is 4 meters, and there is no minimum spacing. The trailer (or its load) may overhang the towing vehicle.

Safe Trailer Loading

Each trailer has a maximum safe laden weight. Overloading a trailer beyond this weight can compromise the trailer's body, chassis, brake systems, suspension and/or coupling. The maximum safe laden weight minus the unladen weight gives you the maximum load (including objects, people and animals) that the trailer can carry.

To arrange loads safely:

  • Check that any goods or animals inside or on your trailer are placed where they won't injure anyone or distract the driver.
  • If following another vehicle, make sure that any passengers are sitting in a safe position, using a safety belt or child restraint.
  • Spread a load of goods out evenly across the floor or deck of the trailer, to keep its height as low as possible.
  • If you have to stack the load, put larger and heavier items at the bottom.
  • If possible, arrange loads so they don't project outside the body of the trailer. Minimize any projecting loads so you reduce the risk of injury to the driver, passengers, and other road users.
  • Position loads, especially the heavier items, on trailers as close to the axle as possible. Avoid placing heavier loads towards the rear of the trailer. Ensure there is a downward force at the point of attachment, to improve the handling characteristics when you are towing.
  • If part of the load is removed during the journey, you may need to rearrange and re-secure the rest of the load.
Securing Trailer Loads

All loads on trailers should be properly restrained so they can't shift around while the vehicle is moving. All objects should be restrained by being:

  • Securely packed inside compartments that are rigidly attached to the trailer, or
  • Held securely in racks or cradles or frames designed to fit that size of the object and which are rigidly attached to the trailer, or
  • Held by lashings (webbing straps, ropes, chains) or clamps securely attached to appropriate anchorage points (rails, hooks or eyes) on the trailer.

When you secure a load, bear in mind that it will try to move:

  • Forwards when the vehicle brakes.
  • Sideways when the vehicle turns.
  • Backward when the vehicle accelerates.
  • Upwards when the vehicle goes over bumps.

If you're using lashings to secure a load, you'll need to work out the strength of the lashings - known as ‘lashing capacity’.  Look on the lashing or its packaging for a figure (in kilograms) besides ‘lashing capacity’. If you see ‘breaking strength’ – then the lashing capacity will be half of this figure. Fasten your load to the vehicle using as many lashings as required to achieve a combined lashing capacity equal to at least twice the weight of the load.

Note: A minimum of two lashings should be used to prevent the load, or part of the load, from twisting, rotating, pivoting or slewing. Secure lashings to suitable anchorage points (rails, hooks or eyes) on the trailer.

Trailer Maintenance

Regular maintenance of your trailer is very important:

  • Check tire pressures, and look for signs of wear or damage.
  • Clean all lights and reflectors.
  • Check that all lights are working condition.
  • Check with your local garage to ensure the tow coupling and brake mechanisms are well lubricated.
  • Jack the trailer up and spin the wheels, listening for rumbling noises and feeling for wheel sway, which indicates worn wheel bearings and unfastened nuts.
  • Check that all tie-down points are tight.

A poorly maintained trailer can be a hazard to yourself and other road users. No matter how good you are at towing, a badly maintained trailer poses a significant risk to the safety of all road users.

Curious or confused? Here’s some information to help!

Adequate knowledge of trailers is necessary for responsible ownership. The information provided here will introduce you to common technical terms, relevant NZTA regulations, and basic operational guidelines. To learn more, visit NZTA online or any other relevant sources.

Technical Definitions
Light Trailers

Light trailers are vehicles without motive power (i.e. they do not have the ability to propel themselves) and have a maximum gross vehicle mass (GVM) or gross laden weight (GLW) of 3500kg or less. Light trailers includes class TA trailers (GVM < 750kg) and class TB (750kg ≤ GVM < 3500kg).

Service & Parking Brakes

Trailer service brakes engage, and often regulate, the trailer’s brake effort in conjunction with, or in relation to, the towing vehicle’s brake application, and assists the towing vehicle to slow down and stop.

A trailer parking brake holds an already immobile trailer and is capable of remaining applied for an indefinite period without further attention. Unlike service brakes, parking brakes are not used in conjunction with the towing vehicle to slow down and stop.

Disc Brakes

Trailer mounted disc brakes consist of an exposed, disc-shaped rotor and an edge mounted caliper. The caliper compresses brake pads against the rotor, which is, in turn, reduces the wheel’s rotational speed. It offers a simplistic, low maintenance trailer braking option that is mechanically or hydraulically operated. They are suitable for all braking applications and can be submerged in the water safely.

Mechanical disk brakes: Hydraulic disk brakes:
Cheaper than hydraulic disk brakes. Greater reliability than mechanical disk brakes.
Less responsive than hydraulic disk brakes. Equalizes brake power between all brakes.
Cable operated, and therefore require frequent cable tension adjustments. No frequent adjustments are required.
Drum Brakes

Drum brakes house its major components inside a large metal drum that rotates along with the wheel. By means of a hydraulic or electrical mechanism, brake pads are pressed outwards against the inside of the drum, reducing rotational speed. This brake type offers an economical and effective braking solution, whilst also providing smooth, damped braking that is ideal for fragile goods or animal transportation.

Hydraulic drum brakes: Electric drum brakes:
Offer smooth, damped braking action. Effective and efficient braking option.
Requires no electrical connection with the towing vehicle. Offers adjustable brake power by means of a trailer-mounted or in-cab brake controller.
Greater reliability than electric drum brakes. Easily mated to a break-away brake system.
Not as efficient as disk brakes. Used in both direct and indirect braking systems.
Built-in, independent, mechanical parking brakes are available.
Indirect Braking Systems

Indirect braking systems, or indirect service brakes, operate without direct input from the driver of the tow vehicle. They can be either inertia-activated or electric (brake-light activated), and both disc brakes and drum brakes can be used in this system. If electrically activated brakes are used, a trailer-mounted brake controller is needed to adjust the braking force. Indirect braking systems are the most commonly used braking systems on trailers rated GLW (Gross Laden Weight) ≤ 2500kg, and cannot by law be used on trailers rated between 2501kg ≤ GLW ≤ 3500kg.

Inertia-activated systems:

Pros: Cons:
No dedicated towing vehicle required. Braking not operable in reverse.
Inexpensive and reliable. Deactivation of brakes required before reversing.
Low maintenance.

Electric (brake-light activated) systems:

Pros: Cons:
No dedicated towing vehicle required. Braking not as advanced as direct electric brake systems.
Braking operable in reverse. Higher maintenance drum brakes are used.
Includes mechanical parking brake.
Direct Braking Systems

Direct braking systems, or direct service brakes, operate as a direct result of braking input from the driver of the tow vehicle. They are load–adjustable and incorporate an emergency over-ride function mounted near the driver’s seat, which operates the trailer brakes independently of the tow vehicle. Brake types used for direct systems are hydraulic disc and electric drum brakes. Trailers rated between 2501kg ≤ GLW (Gross Laden Weight) ≤ 3500kg are required by law to employ direct braking systems.

Electric-hydraulic systems:

Pros: Cons:
Can allow for no dedicated towing vehicle. An additional mechanical parking brake is required.
Allows the use of hydraulic disk brakes. Unfamiliar brake system in New Zealand.
Includes break-away brake system. Pending NZTA assessment and approval.
Braking operable in reverse.

Electric systems:

Pros: Cons:
Provides accurate, proportional brake control. Dedicated towing vehicle is required.
Includes built-in mechanical parking brake. Higher maintenance drum brakes are used.
Easily mated with a break-away brake system. New Zealand tried and tested brake system.
Braking operable in reverse.
Break-away Brake Systems

A break-away brake system is a service or parking brake fitted to a trailer that ensures, under all conditions of use, that if the trailer is unintentionally disconnected from its towing vehicle, the brakes will immediately engage in order to bring the trailer to a halt. The action time of the break-away brake must be a minimum of 15 minutes.

Non-equalizing & Equalizing Suspension

A trailer that utilizes two or more axles, mounted independently of each other, cannot equally distribute the trailer weight between the axles when traversing uneven terrain, or when the towing vehicle’s tow ball and trailer coupling are not at the same height. Such a suspension system is classed as a non-equalizing suspension system. Although an economical option, periodic point loading can cause bearing and suspension failure, and result in poor towing characteristics.

Equalizing suspension systems consist of multiple axles with a rocker arm between each axle. This enables the axles to have greater, independent vertical travel whilst maintaining full weight carrying capacity at any point and effectively distributes the weight between all axles. Axle overloading is mitigated, prolonging axle, hub and bearing service life, and towing characteristics are improved.

NZTA Brake Regulations
Introduction

The New Zealand Transport Agency (NZTA) introduced a new regulation, the Land Transport Rule: Light-vehicle Brakes 2002 (Rule 32014), on 1 April 2002. This rule sets the safety requirements and standards of brake systems installed on all Light Vehicles and Light Trailers, new and existing, with a Gross Laden Weight (GLW) of up to 3500kg. The Gross Laden Weight refers to the maximum combined weight of the trailer and payload. A summary of the brake requirements with respect to the Light Trailer GLW categories not exceeding 3500kg is given below.

Trailer GLW: 0kg - 2000kg

Trailers with a Gross Laden Weight of GLW < 2000kg do not require service nor parking brakes. However, if brakes are fitted, then the following requirements apply:

  • Both wheels of at least one axle must be braked;
  • It must be fitted with a safety chain (compliant with ADR62 Determination of 1995), connected between the towing vehicle and the trailer.
  • The load must not be transferred to an un-braked axle during braking; and
  • Combined with the towing vehicle’s service brakes, must be capable of stopping the combination of towing vehicle and trailer within a distance of 7 meters from a speed of 30km/hr.

It is critical to consider the towing capacity of the towing vehicle when towing a non-braked trailer.

Trailer GLW: 2001kg – 2500kg

Trailers with a Gross Laden Weight of 2001kg ≤ GLW ≤ 2500kg must be fitted with service brakes, but a parking brake is not required. The service brakes may be either indirect braking or direct braking systems and must meet the following requirements:

  • Both wheels of at least one axle must be braked;
  • The load must not be transferred to an un-braked axle during braking;
  • Combined with the towing vehicle’s service brakes, must be capable of stopping the combination of towing vehicle and trailer within a distance of 7 meters from a speed of 30km/hr; and
  • The coupling system must show the manufacturer’s load rating corresponds with the GLW the trailer. It must also be fitted with either two (2) crossed safety chains (compliant with ADR62 Determination of 1995), mechanical connections between the towing vehicle and the trailer, or an emergency breakaway brake.
Trailer GLW: 2501kg – 3500kg

Trailers with a Gross Laden Weight of 2501kg ≤ GLW ≤ 3500kg must be fitted with direct service brakes, a break-away brake system, and an independent mechanical parking brake. Safety chains are not required because the emergency break-away brake system is installed.

The service brakes must be a direct braking system, and must meet the following requirements:

  • Must be fitted with an in-cab brake controller; and
  • Combined with the towing vehicle’s service brakes, must be capable of stopping the combination of towing vehicle and trailer within a distance of 7 meters from a speed of 30km/hr.

The parking brake must be a mechanical brake, independent of the service brake, and meet the following requirements:

  • Both wheels of at least one axle must be braked;
  • Must be capable of stopping the trailer within a distance of 18 meters from a speed of 30km/hr, or alternatively, be capable of holding the trailer at rest on a slope of 1 in 5.
NZTA Dimension Limits
Light Trailers: Maximum Length

The maximum overall length for a light trailer (including drawbar and load) is 12.5 meters. The maximum overall length for a rigid tow vehicle and light trailer combination (including load, but excluding collapsible mirrors) is 22 meters.

The maximum rear overhang for light trailers is 4 meters and is measured from the halfway point between two axles, or the 2nd axle in a tri-axle set, to the rear of the trailer or its load, whichever is greater.

For light trailers, the front overhang is the distance from the center of the tow coupling, to the foremost point of the vehicle (including its load). The maximum is 2.04 meters radius arc ahead of the tow coupling.

The inter-vehicle spacing is the distance between the towing vehicle (excluding the tow coupling shroud) and the trailer (excluding the drawbar but including the load). The maximum for light trailers is 4 meters, and there is no minimum spacing. The trailer (or its load) may overhang the towing vehicle.

Light Trailers: Maximum Width

The maximum width for a light trailer (including its load) is 2.55 meters (excluding side marker lights and direction indicators and the bulge towards the bottom of the tires).

Loads that overhang the outside of the body or deck of the vehicle by more than 1m to the front or rear, or more than 200 millimeters to the left or right side, need to carry special warning devices attached to the overhanging end(s) of the load. The total width of a loaded light trailer is therefore 2.95 meters. Visit www.nzta.govt.nz for more information on the aforementioned special warning devices.

Light Trailers: Maximum Allowable Height

The maximum allowable height (including the load) is 4.3 meters. All vehicles must be loaded in a safe manner, with a height appropriate for the type of load.

Trailer Operational Guidelines
Safe Trailer Towing

Both light and heavy vehicles towing a trailer are limited to a maximum open-road speed of 90km/h. School buses towing a trailer are limited to the maximum open road speed of 80km/h. Drivers also need to obey any lower speed limits that apply on particular roads.

If you tow a light trailer, you need to be aware that the trailer can impose a large weight on the rear of your tow vehicle. This weight can, by lever action through the chassis of the vehicle, reduce the effective mass bearing on the front axle(s) of your vehicle. It is important, therefore, that you load your trailer carefully so the load is distributed centrally over the axle(s) of the trailer. This will allow your vehicle to maintain the front-wheel grip on the road, so you can continue to steer it safely.

Note: Look in your vehicle manual for the maximum weight your vehicle can tow. In addition, there needs to be a downward force, approximately 10% of the weight of the trailer and its load, on the tow coupling of a simple trailer for stable towing.

The maximum rear overhang for light trailers is 4 meters and is measured from the halfway point between two axles, or the 2nd axle in a tri-axle set, to the rear of the trailer or its load, whichever is greater.

For light trailers, the front overhang is the distance from the center of the tow coupling, to the foremost point of the vehicle (including its load). The maximum is 2.04 meters radius arc ahead of the tow coupling.

The inter-vehicle spacing is the distance between the towing vehicle (excluding the tow coupling shroud) and the trailer (excluding the drawbar but including the load). The maximum for light trailers is 4 meters, and there is no minimum spacing. The trailer (or its load) may overhang the towing vehicle.

Safe Trailer Loading

Each trailer has a maximum safe laden weight. Overloading a trailer beyond this weight can compromise the trailer's body, chassis, brake systems, suspension and/or coupling. The maximum safe laden weight minus the unladen weight gives you the maximum load (including objects, people and animals) that the trailer can carry.

To arrange loads safely:

  • Check that any goods or animals inside or on your trailer are placed where they won't injure anyone or distract the driver.
  • If following another vehicle, make sure that any passengers are sitting in a safe position, using a safety belt or child restraint.
  • Spread a load of goods out evenly across the floor or deck of the trailer, to keep its height as low as possible.
  • If you have to stack the load, put larger and heavier items at the bottom.
  • If possible, arrange loads so they don't project outside the body of the trailer. Minimize any projecting loads so you reduce the risk of injury to the driver, passengers, and other road users.
  • Position loads, especially the heavier items, on trailers as close to the axle as possible. Avoid placing heavier loads towards the rear of the trailer. Ensure there is a downward force at the point of attachment, to improve the handling characteristics when you are towing.
  • If part of the load is removed during the journey, you may need to rearrange and re-secure the rest of the load.
Securing Trailer Loads

All loads on trailers should be properly restrained so they can't shift around while the vehicle is moving. All objects should be restrained by being:

  • Securely packed inside compartments that are rigidly attached to the trailer, or
  • Held securely in racks or cradles or frames designed to fit that size of the object and which are rigidly attached to the trailer, or
  • Held by lashings (webbing straps, ropes, chains) or clamps securely attached to appropriate anchorage points (rails, hooks or eyes) on the trailer.

When you secure a load, bear in mind that it will try to move:

  • Forwards when the vehicle brakes.
  • Sideways when the vehicle turns.
  • Backward when the vehicle accelerates.
  • Upwards when the vehicle goes over bumps.

If you're using lashings to secure a load, you'll need to work out the strength of the lashings - known as ‘lashing capacity’.  Look on the lashing or its packaging for a figure (in kilograms) besides ‘lashing capacity’. If you see ‘breaking strength’ – then the lashing capacity will be half of this figure. Fasten your load to the vehicle using as many lashings as required to achieve a combined lashing capacity equal to at least twice the weight of the load.

Note: A minimum of two lashings should be used to prevent the load, or part of the load, from twisting, rotating, pivoting or slewing. Secure lashings to suitable anchorage points (rails, hooks or eyes) on the trailer.

Trailer Maintenance

Regular maintenance of your trailer is very important:

  • Check tire pressures, and look for signs of wear or damage.
  • Clean all lights and reflectors.
  • Check that all lights are working condition.
  • Check with your local garage to ensure the tow coupling and brake mechanisms are well lubricated.
  • Jack the trailer up and spin the wheels, listening for rumbling noises and feeling for wheel sway, which indicates worn wheel bearings and unfastened nuts.
  • Check that all tie-down points are tight.

A poorly maintained trailer can be a hazard to yourself and other road users. No matter how good you are at towing, a badly maintained trailer poses a significant risk to the safety of all road users.

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