New Sasol GTC cars set for thrills

The iconic Grand Prix Circuit will present a new challenge to the GTC drivers as they tackle the country’s fastest racetrack on June 16.

Suzuki’s new Swift hatch and sedan in SA

Suzuki kicks off its new model assault with an all new Swift hatchback and standalone sedan called the Dzire.

Roofboxes - gimmick or godsend?

2009-10-21 12:46

Lance Branquinho

Conventional wisdom says adding stowage space (and associated mass) to the roof of your vehicle is a recipe for disaster - exacerbating any handling foibles, especially during emergency avoidance manoeuvres.

Best to tow everything you (or the family) need for a weekend away with a trailer then, right?

Well, not necessarily, especially when you consider independently suspended trailers are a rarity and tyre blowouts always a gnawing doubt in the back of one's mind.

As an alternative Thule, the Swedish mobility stowage specialist, has some innovative roofbox solutions for South Africans who wish to travel with all their weekend (or holiday) kit, yet could do without the hassle of a trailer.

The advantages of a roofbox are diffuse. There is no trailer license, tyres to replace, towbar to attach or spare square metres in the garage or garden necessary to park a trailer when not in use.

With the Thule roofbox you simply stick it on top, fill it up with kit, and off you go.

Is it more economical though? Mounting a roofbox on top of your car is sure to increase drag appreciably and play havoc with fuel consumption figures, right?

Mechanical drag versus total frontal area drag coefficients

To dispel the common misconception of roofboxes being more punishing on fuel economy than a conventional trailer Thule conducted some tests at Gerotek recently.

A Subaru Forester XT automatic was equipped with Thule’s Atlantis 200 (a medium-sized model) and set off on the famed three kilometre banked oval at a true road speed of 120km/h for 75km.

The test was then repeated with a 2.1m Thule trailer. Both runs had the Forester operating without climate control and with 65kg worth of weight loaded into either stowage solution.

When the fuel consumption results were tabulated the roofbox bested the trailer by half a litre. The Forester returning figures of 10.8l/100km with the roofbox on top compared to 11.4l/100km towing the trailer.

Factor in Forester XT’s turbocharged 2.5l flat-four's generous helping of rotational force at lower engine speeds (which is where the test was operating in top gear at 120km/h) and it stands to reason the consumption gap between roofbox and trailer would be even more pronounced in a less powerful car.

A right-sized solution

Obviously a trailer can take more volume, but how often do you pack one optimally (to the brim) for a weekend away?

Besides, with the Atlantis roofbox able to accommodate 440l and 75kg worth of kit, whilst only weighing 17kg itself and storing seamlessly in some nether region of your garage, it would appear to make an awful lot of sense.

With Thule’s roofboxes featuring dual hinged actuation they can be loaded from either the left- or right-hand side too and are stupefyingly easy to attach to your car’s roofrails.

If you still have doubts about a stowage solution which adds mass to the roof of your car, considering the origins of Thule.

Swedes have been travelling for with their Thule roofboxes on some of the most forbidding roads imaginable over vast distances for years now, and you know how safety conscious they are. After all, these are the people who vote the world’s model welfare state into power again and again…

Makes one think, perhaps it really is better on top…


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