Combi Roofbox Solution

[London Les]

With the holiday season approaching I thought the forum might be interested in my set-up.

- Atera ASR roofbars (I went for steel, although they do aluminium aero sections too). The Octavia bars are 122cm long and over hang the roof rails by about 50mm on both sides. The bars are galvanised plastic-coated box sections.

- Thule Atlantic 200. Very pleased with the box, its about 3/4 width of the roof, can be opened from either side, has twist grip clamps rather than U-bolts, and (just) fits without removing/lowering the aerial. I went for 3/4 width box, so I could add a couple of bikes later, although it might be a bit tight for this.

Am now preparing the kitchen sink for the bank holiday camping trip!

[nickcoll]

Just as a matter of interest, how much does it affect the fuel consumption when you have this on? I have seen figures of around 5mpg reported, which would seem appropriate as both the CD and frontal area must be very significantly negatively affected.

[London Les]

Yes - I'm wondering myself. I have a decent motorway trip planning next weekend. I'll report back - I'm expecting around 10%.

The box is a slippery shape, but I can imagine both that and the bars disrupt the streamlines around the roof in a big way.

[London Les]

According to maxidot the roofbox knocked 8mpg (roughly 15%) off fuel consumption. I had been getting 46mpg on a motorway run, and now get 38mpg - its also noticeable when cruising that more gas is needed.

Should note this is based on one fully loaded run in terrible weather - the South coast this bank holiday anyone?!

Still, the box had a bigger impact than I expected.

[Tomdeswrig]

Would you increase the tyre pressure to fully laden with a roofbox?

[London Les]

I increased the pressures to I think 32 front, 37 rear which is about halfway between normal and fully laden.

The extra weight is 16kgs (box) + say 4kgs (bars) + about 40kgs contents = 60kgs so the equivalent of another passenger on the roof.

[Tomdeswrig]

Hi Thats what I have done in tha past. If the car is not towing or has young children and some luggage /roofbox it feels like it is too light on the sterring at full pressure.

Cheers

[Tomdeswrig]

Hi All being well a picture of my set up should be in this reply? Thule Aluminium roof bars used.

[London Les]

Nice pic. A key factor for me was the clearance between the rear bar and the aerial.

I see from the pics that for your box and mine, there is just enough space to place the rear bar just behind the middle support on the car roof bar and the box to clear the aerial.

I know its possible to lower or remove the aerial, but I'd rather not.