Cargo Boxes

[borderfox]

I continue to work on figuring out what my setup should look like. Lots of moving parts to consider which leads me to this query..

- Cargo Boxes

I've watched a tonne of Berlingo Micro-camper van setups on YouTube at this point. I see very few tend to bother with a cargo box but I've come around to thinking that it can help a lot - getting a lot of clutter out of the way of the van.

The two downsides appear to be 1. Cost and 2. Worse fuel economy. On the first one, I guess all of this kit is expensive these days so that is what it is. On the fuel economy thing, when researching this, I see some people saying it can be a 25% drag on fuel economy while others say having the Cargo Box on board has little to no negative effect on fuel economy.

My question: Have any of you used these cargo boxes and what was your experience relative to fuel economy??
Additionally, I see they're lockable but are those locks robust?

[ffrenchie]

25% sounds a bit of an exaggeration, I've read 3% for a roof rack so I would imagine a streamlined box would not add much more than that.

[ItsGreen]

As in a roof box, or one that fastens to the towbar?

I've not used one on mine, but I have a couple of kayaks up there quite a often. I haven't really noticed any difference in fuel consumption either way. Not saying there is no difference, but if there is, it's really small.

[Gryffindor]

I used to wonder why truck trailers have flat fronts - seems counter-intuitive in terms of wind resistance and streamlining right? Then some years ago I noticed a few M&S trailers with rounded front edges a bit like sausages cut in half longways. Then they got phased out.

Turns out that a flat front surface is actually good - when going at speed, an 'air cushion' is formed in front of the trailer front, creating a natural airflow around the box, plus the cushion's profile adapts for different road and wind speeds. So Thule type roof boxes are more style than function, or as much as of both.

What is not good is cylindrical roof bars across the roof - they mess badly with airflow and cause a lot of drag. Think of the vertical struts between the wings of biplanes - they were long from front to back and gently tapered. As for the rectangular roof bars I made last year from bit of wood from Wickes - never again!

I don't know but I'd imagine that a cargo box on a roof would be more fuel efficient if it has a good load in it vs. being empty, because it is less likely to be buffeted and will be more stable in winds, thus smoothing out variations during travel. Bit like putting bags of sand in trailers and caravans.

[borderfox]

As in a roof box, or one that fastens to the towbar?

Yeah, it was the roof box I had in mind rather than the towbar box.

[ffrenchie]

What is not good is cylindrical roof bars across the roof - they mess badly with airflow and cause a lot of drag. Think of the vertical struts between the wings of biplanes - they were long from front to back and gently tapered. As for the rectangular roof bars I made last year from bit of wood from Wickes - never again!

I had a Nissan van with square section ladder rack on the roof and when I went over 50mph it sounded like i was being chased by banshees. It only went on when it was needed.

[Zion]

Aye, it sounds like those corrugated plastic snake toys that had chewing gum in the tail, and you pulled that out, swung it round your head - it made an eerie melodic whistling noise. Anyone else remember those? Very reminiscent of a roof rack sound.

[boop]

Been using a roof box for snowboarding trips. Depending on the box size and shape, it absolutely adds significantly to fuel consumption. At city speeds not at all. Anything above 60 mph a underpowered car like a Berlingo will struggle.

250 horsepower Volvo with a streamlined factory box that looks like it's glued to the roof - that's the 3% mentioned above.

[ItsGreen]

Aye, it sounds like those corrugated plastic snake toys that had chewing gum in the tail, and you pulled that out, swung it round your head - it made an eerie melodic whistling noise. Anyone else remember those? Very reminiscent of a roof rack sound.

Cable tie some scaffolding pad around the bars.