Roof Boxes: A buyer’s guide

Are you experiencing space or weight restrictions with your outfits? A roof box might be the answer. It offers extra storage and doesn’t exceed your MTPLM.
Since we were able to get our caravan to a public weighbridge, I have worried about how much stuff we can pack on board. We do fine most of time. However, when we have to carry the full awning onboard for longer trips we had to make some sacrifices. I say ‘had’ because the roof box has provided us with the solution.

We first had to understand how the caravan roof boxes would attach to our Range Rover. There were no roof rails. It was the beginning of a steep learning curve as to how roof boxes attach.

A friend had a similar car that has a roofbox, so we went to his house. The Range Rovers’ six mounting points are concealed beneath a plastic-hinged cover. Our friend had used four of the front points to anchor a pair on bars. The roof box was then attached to the bar.


Each mount is protected by a lockable covering and a bolt. The bars were aerofoil designed to reduce drag and wind noise. It was as easy as ordering a pair of these and we were in business.

Size and shape

The size and shape are the next things to consider. A large box offers more storage, and can be easily opened from either end. It is much better to have a narrower or wider box if you are carrying multiple items, such a bicycle, on the roof.

The length is not usually restricted. However, you need to be able to open any tailgate while the roofbox is still in place. This can be an issue if the box is too large at the front. You won’t notice it when you drive.

Make sure that the box is large enough to fit any long items. In our case, that meant our awning poles. But, it was possible to get the windbreak in.

Even without these items it is worthwhile to get a longer box.

Roof bars

Roof boxes attach on to roof bars that cross the car. The bars can attach directly to the bodywork, to existing rails, or to pre-existing mounting holes in the roof. A few cars have old-fashioned raingutters that can be used as clamps.

Some cars have no mounting points on the roof, like the old Passat CC that the editor was using. The Thule roof clamps were installed between the roof swage line, and below the top edge of his window frames.

Although it was hard to mount, it was stable as a rock once it was fixed. Thule’s aerodynamically shaped WingBars, which are 55% lighter drag than their predecessors.

We were presented with two options. To source suitable roof bars and roof rails, or to attach roof bars to the car’s bodies, it seemed. We chose to have body clamping brackets for aerofoil rails, to keep the car’s exterior clean.

Locking mechanisms

It may be necessary to fasten the roof box lid at more than one place in order for it to be secure. This is why manufacturers have developed central locking devices.

The problem is that if your roof box has bulky items holding it up, you may have to push down on the front and middle of the lid together before you can turn off the key. This can often require two people.

Kamei, a Japanese manufacturer, developed “pull-to click-shut” mechanisms. In this system, you pull down on each points until they click shut. Next, you turn the key.

Weight considerations

Unbeknownst to us, the roof box’s weight and the roof bars’ combined weight was not something we had considered. Each car model has a different roof-loading limit. These range between 50 to 100kg. The manual of the vehicle will contain more details.

Roof boxes with roof bars weigh approximately 12 kg to 25kg. This weight must first be subtracted from the car’s roof loading limit in order to determine the maximum weight that can go into the roofbox. It is also important to take into consideration the box’s specific load limit. This can usually be between 50 and 75 kilograms.

Capacity

For a small half-width box, the capacity is 250 litres. For a full-width box, it can be 600 litres.

Comparatively, a VW Golf has a trunk capacity of 380 L and the Volvo V70 has a max boot volume of 575 L. It’s ideal for long gear like umbrellas and windbreaks, as well as wet and sandy beach gear.

Opening options

Roof boxes can open either from the back, one side, or both. The benefit of rear or dual side opening is that the box can be accessed from either side. This makes the job easier when attaching to the roof bars or loading.

Our choice

We determined that any roof box needed to be large enough for our awning, a full-sized Isabella of 51 kg with its poles. You would need a large container. We thought it might be a nice idea to put a few lightweight bikes on the roof bars. Therefore, we didn’t want to buy a huge box.

After much research we finally settled for the Thule Motion 800. It is high quality with a capacity that holds 460 litres, and a 75 kg load rating. The box weights 19kg, or 25kg including the roof bars.

This car roof can support 100 kg. It’s capable of driving at 130 kmh (80 miles per hour), which is sufficient for us.

How much? The price of the box was only PS439.95 The box cost PS439.95, which included the fixings with locks and bars.

We found it easy to install the roof bar and roof box – once the instructions were understood! Though it did take us two to get everything on, this is the norm with roof boxes.

The height of the new roofbox makes access difficult. The caravan step is great, and you can even stand on the car seat while holding onto the roof bars.

The awning can remain in the roofbox until it is ready to be put up. As an added bonus the roof bars give us the ability to carry other items.

You might have trouble fitting some cars without roof bars. Have a look at YouTube for solutions.