But there’s a limit to how much you can pile on top of your trusty SUV, and it may be less than you think.

What are the potential consequences of overloading your roof rack?

1. Too much weight can structurally damage the vehicle’s roof pillars.
2. Overloading a roof rack can break the rack.
3. Most importantly, too much gear on the roof can affect the control and stability of your vehicle and cause a rollover.

To reduce these risks, roof rack and car manufacturers have determined the load limits of their products.

Vehicle limit

Gross Vehicle Mass (GVM) refers to a car’s maximum legal weight. This is the weight of the vehicle, plus everything onboard, including passengers, fuel, luggage and accessories.

When fitting a roof rack, keep in mind that the rack and everything on it must be included when calculating the vehicle’s total weight. For this reason, some people prefer a quality aluminium rack rather than one made from heavy steel.

As well as an overall weight limit, a vehicle will also have a roof load limit. You might be able to find this figure in the owner’s manual, but if not, you’ll need to contact the car maker.

When loading your car according to this weight limit, there are a couple of things to keep in mind.

• The weight limit is usually a dynamic rating. That’s the limit when the vehicle is in motion. There may be a higher limit when the car’s stationary. Contact the manufacturer if you need to know this figure.
• The rating is normally based on driving on sealed roads, though the car maker might also include an off-road limit. Driving on rough outback tracks puts much more stress on the roof and rack.

Roof rack limit

Manufacturers apply weight limits to roof racks. If this is greater than the car maker’s roof weight limit, then it’s important to follow the vehicle’s lower limit.

A roof rack’s limit is usually a dynamic rating for a vehicle travelling on good-quality sealed roads. The static (stationary) rating is likely to be significantly higher, and this could be important if you’re fitting a rooftop tent.

Keep in mind that the static load rating of the vehicle’s roof must be considered when calculating the tent’s weight and the camper sleeping inside.

Staying upright

Vehicle and roof rack weight limit calculations are largely based on the strength of the products rather than the stability of the vehicle.

The most important part of any trip is the safety of vehicle occupants. Keeping extra weight down low on the car will reduce the risk of a potentially catastrophic rollover.

It’s best to store lighter, bulky items – like swags – up top instead of heavy objects like spare wheels and toolboxes. Some weighty items can be stored securely inside the vehicle, while spare wheels can be carried on properly constructed and fitted holders lower down.

Where and how to carry extra fuel is a whole separate article, but be aware that fuel-carrying rules vary between states. If you’re planning a lot of trips where extra fuel is needed, the ideal container is a long-range tank.

Spreading the weight evenly over the entire area of the roof rack can also help with vehicle stability and control, and prevents uneven stress across the rack and roof.

Securing the load

Unfortunately – for some of us – the ′70s are over. Attaching a ton of surf gear on the roof with well-worn octopus straps has gone the way of velour-lined Sandman panel vans.

A rooftop load should be secured to suitable attachment points using rated equipment that shows the load weight it can restrain. There are several types of restraints, including webbing straps and synthetic ropes.

The National Transport Commission’s Load Restraint Guide for Light Vehicles is an excellent resource.

What about insurance?

Most car insurance policies have a clause stating there’s no cover if the vehicle’s carrying a load heavier than it was built to carry.