7 common mistakes when packing roof racks

2 November, 2023

Roof racks can provide some handy extra storage space for travellers, especially on bigger road trips. In many cases they’re an indispensable accessory that eliminates the need for towing a trailer and freeing up extra load-carrying space inside the vehicle.

However all too often a vehicle’s roof rack and the way its packed is taken for granted without enough care and thought in regard to safety and mistakes that can create problems. Utilising the rack properly and relative to its design and load-carrying capacity, is important and really does need careful consideration.

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Over reliance on the vehicle’s roof rack by overloading with too much gear that’s badly packed, is dangerous. It affects the vehicle’s handling and stability, fuel economy and even its driving characteristics. In short, there are a lot of common mistakes or oversights that are worth noting.

1. Exceeding the legal load ratings and limits for roof racks in WA

There are various legal considerations for vehicle roof racks in Western Australia. The maximum allowable width for a fitted roof rack is 2.5m and it cannot extend more than 150mm either side of the vehicle’s width. Roof loads are not permitted to extend more than 1.2m beyond the front or the rear of a vehicle, but not at the same time.

The question of the maximum load you can put on the roof rack depends on its type and quality, and its maximum rated load from the manufacturer.

Generally, on smaller sedans a maximum of 50kg should be observed whilst 100kg is more typically recommended for larger vehicles and four-wheel drives. It is crucial that the driver be aware of the roof rack or roof bar manufacturer’s load specification, something that can be checked easily according to the brand or the manufacturer themselves.

2. Not checking the maximum roof load for your vehicle

The strength and rating of the roof rack itself are vital but so is the maximum load rating for the vehicle that the roof rack is fitted to. This is important when owners fit after-market roof racks but neglect to check what the actual maximum roof load is. Typically, this information can be found in the vehicle’s manual.

Smaller cars obviously have a limited roof load capacity whether it be by the roof gutters or now through the more common roof railing systems mounted on the roof. Larger four-wheel drives for example, have a much higher roof load rating. A Toyota Landcruiser 200 series has a maximum roof loading of 200kg but this should not be confused with how much weight can be put up top.

The weight of the roof rack itself (especially if it’s steel) will already have significant weight before anything is put on it. So you’ll need to add this into your total roof load calculations.

3. Not centring or loading the roof rack correctly

Packing a roof rack without a good system and not paying attention to centring the load properly is a common mistake. Items should be laid as flat as possible with the heaviest, more centred. Avoid loading things standing upright that are high. This may be unavoidable for fuel cans and gas bottles because they need to be outside but consider other alternatives such as rear carriers and if not lay them flat once they’re used. Anything that increases wind resistance increases fuel consumption so keeping things low is a wise move.

With some roof rack set-ups, it’s possible to purchase wind deflectors that can be installed at the front of the frame. The idea is to deflect the oncoming air more smoothly at an angle up and over the top.

What should never be packed on a roof rack without the correct bracing or reinforcement is large, thin sheets of board or material that will lie flat but once caught by the oncoming wind and a change in the pressure above, will want to lift and fly. It’s one of the most common mistakes when using a roof rack and often sees the sheet bend and break if it doesn’t take off first.

Thought should also be given to placing things in ways where they can be tied down securely, either separately or as part of other items alongside. Always work on the principle of keeping as many heavy items as possible in the boot or safely behind a cargo barrier, not on the roof rack wherever possible. This lowers the vehicle’s centre of gravity rather than the opposite.

4. Not using the right tie downs or strapping

Laying items out effectively on the rack is relatively easy. Securing them properly is the challenge. Start with good quality purpose-made tie downs or straps. To secure heavier items most effectively there is no better alternative than a ratchet strap. It will tension as far as you wish and will not loosen.

A common and effective alternative for lighter applications is the cam buckle strap. These can be tensioned well but need to be checked more regularly during trips, especially if the straps and buckle are a little worn with use. Different forms of quality cord can also work provided a tensioning loop is tied in to allow the cord to be doubled down hard onto the rack frame.

Once secured, take the time to ensure there are no loose ends that can flick or flap annoyingly on the car’s roof. Shorten them up into folds or small rolls and use a little insulation tape to secure them against the roof rack. If a length of strap is exposed under tension, the wind resistance will cause it to vibrate or create a whirring sound. The best solution is to tie the strap in such a way where it does not have a long exposed length.

5. Overloading poor quality roof racks

Not to be underestimated is the quality of the roof rack itself and its fittings. Although far less common these days, the cheaper, lightweight, alloy style of racks can be prone to failure and weld cracking through corrosion if they’ve been in use for many years. They are certainly not suitable for any significant load carrying, particularly on rough terrain.

As a part of good practice, check your roof rack fixing points to see whether anything has become loose or weakened over time. Loaded four-wheel drives, especially if subject to plenty of harsh off-road rocking and rolling or long journeys over hundreds of kilometres of corrugations, can expose failings or cracks in the roof rack fixings. Many a seasoned traveller to the north of the country has discovered just how damaging road corrugations can be on any vehicle accessory and even the vehicle itself.

There is a difference between what are known as static and dynamic load ratings. Static load limits refer to sealed roads and highway driving. Dynamic limits take account of harsher road conditions. Basically, this means the maximum roof load carrying capacity for a vehicle will always be lower in dynamic, more stressing conditions such as harsh trails or violent sideways movement.

6. Neglecting wind noise

Annoying wind noise caused by roof racks is not necessarily a safety concern but it’s a common oversight that drivers put up with. Air flow through any structure that is not particularly aerodynamic (such as a square tubed roof rack) will cause increased wind noise. It’s the reason why so much attention is now given to aircraft-wing-style roof bars and why roof racks are becoming very low profile, almost sitting directly on the vehicle roof.

Various approaches have been used to try to eliminate the added noise factor, not all of them successful. Tying bungee cord in a diagonal, spiral fashion around the bar work can help or else taping on some circular foam, that doubles as padding. And ensure there are no exposed holes or ends on the roof bars or rack – these are the problem when it comes to incessant whistling.

7. Not taking the time

Loading up your roof rack and the rest of the vehicle too hastily because you’re trying to beat the traffic or get on the road as quickly as possible is where mistakes happen.

Taking the time to pack your roof rack properly and double check it, is critical because a lack of care can lead to disaster. One small oversight when packing and strapping things down can have devastating consequences, so never be in a rush.