Roof top tents and fuel consuption

Submitted: Sunday, Jun 05, 2011 at 17:08

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Roof Racks, Luggage Trays & Boxes

In this article we look at the pros and cons of using the roof of your vehicle for storage when travelling; discuss what not to carry on your roof; provide some helpful packing hints and finally some

Member - Nip (QLD)

I am thinking of buying a roof top tent. I've waded through most of the previous topics on them and found some interesting stuff however, there has only been one person that i could find that commented on the fuel usage and he didn't think it made much difference to his 80 series.

I have a 100 series cruiser (1HZ plus non-factory turbo) and while it's not too bad on the juice (depends on load and my right foot really) I'd not like it to drop in economy a heap. I was wondering what others have found with their vehicles.

Thanks Nip

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Reply By: Olsen's 4WD Tours and Training - Sunday, Jun 05, 2011 at 18:00

Sunday, Jun 05, 2011 at 18:00

If you already have a rack fitted you will already suffer about 20% extra fuel consumption at highway speeds, and in my experience the tent adds practically nothing.

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Follow Up By: Member - Nip (QLD) - Sunday, Jun 05, 2011 at 18:32

Sunday, Jun 05, 2011 at 18:32

Thanks for that, the roof tray comes and goes (for that fuel consumption reason, plus me not remembering when I go to drive under things) but the rhino racks are a fixture.

If it's little different to just with the rack, that'll be great.

Cheers Nip

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Reply By: Mick O - Sunday, Jun 05, 2011 at 19:46

Sunday, Jun 05, 2011 at 19:46

I'd back David up there. The damage to the fuel economy predominantly comes from the roof rack. With a big trip you tend to be packing a fair bit extra up-top anyway. You can offset the drag of the roof rack by slowing down. At 80 kph, the difference in drag is noticeable and it does compensate in then fuel economy stakes. Same thing occurs without the roof rack. 100kph down to 80kph will often save 15% plus on the fuel economy stakes.

I notice with interest that Kimberley Kampers incorporate a windbreak into their roof top tent offering. The cube I think it's called. This could be a worthwhile consideration with an extra roof bar, some brackets and a piece of stiff ply or aluminium.

Cheers Mick

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Follow Up By: Member - Nip (QLD) - Sunday, Jun 05, 2011 at 20:25

Sunday, Jun 05, 2011 at 20:25

Thanks Mick,

I'd thought about better aerodynamics and think it'd have to be a sensible thing to do so I'd already started planning the wind deflector off the front roof bar for the front of the tent (if we buy one). As you say, you always tend to have stuff stuck up on top if you aren't towing so you've pulled a fair bit off the economy anyway. I note you have a roof top tent on your truck - I assume (hope) you are pleased with it?

Since you have to recognise your own failings I just have to accept that I'm not likely to slow down to 80 kph so the deflector is probably the bast way to go.

Cheers Nip

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Follow Up By: Michael ( Moss Vale NSW) - Monday, Jun 06, 2011 at 19:19

Monday, Jun 06, 2011 at 19:19

Nip!! I responded to a post a few days ago about a similar problem someone had.... Here it is below, MichaelMichael

( Moss Vale NSW) replied:
What about a deflector??? Without the deflector and at highway speeds, i lose about 1.5 LPH.. With the deflector, im back to my 900 ks per tank (115litres).. Click on my pic below for my deflector!!! Michael
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Reply 3 of 3 FollowupID: 729214 Submitted: Thursday, Jun 02, 2011 at 22:42
tommo05 posted:
Michael, never seen that before. I'm well sick of having my fuel economy plummet every time I load up the roof rack. Where do you get one of these whizzbang deflectors?
FollowUp 1 of 2 FollowupID: 729672 Submitted: Monday, Jun 06, 2011 at 18:09
Michael ( Moss Vale NSW) posted:
Tommo!! I made the bars myself and added the deflector. It is just a piece of 6mm Polycarbonate, bolted at the bottom, works well! Michael
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Follow Up By: Michael ( Moss Vale NSW) - Monday, Jun 06, 2011 at 19:27

Monday, Jun 06, 2011 at 19:27

Nip!! Just to add, I made a set of custom roof bars to keep the weight down. They weigh 5 kg each so I save 45kg by not having a steel roof rack. The down side is that I can not carry anything else on the roof but in my case, I normally tow my off road box trailer so everything else goes in that. The difference in drag with the deflector is very noticeable at speed, hence the saving in fuel. Hope this helps, Michael

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Follow Up By: Member - Nip (QLD) - Monday, Jun 06, 2011 at 19:37

Monday, Jun 06, 2011 at 19:37

Thanks Michael,

That looks just the ticket. What brand of tent do you have and are you happy with it?

Cheers Nip

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Follow Up By: Michael ( Moss Vale NSW) - Monday, Jun 06, 2011 at 20:07

Monday, Jun 06, 2011 at 20:07

Nip! I bought the tent, larger skirt, awning and insect screen for the awning from an Ebay seller in Melbourne for $1350 total. He took off $150 or $200, cant really remember. Its all made in South Africa but be careful as a lot come out of china now with a similar price tag. I was in Melbourne for work so i rang the guy and went around to have a look at the quality. Quality is good for the money and i cant pick any difference between the ARB tent i looked at. They can be a pain if you stay in one place for more than a day, packing up just to go for a drive can be a drag, especially if you have the awning and insect mesh set up. But having said that, it is not that hard or time consuming to pack it up. Michael

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Follow Up By: Michael ( Moss Vale NSW) - Monday, Jun 06, 2011 at 21:21

Monday, Jun 06, 2011 at 21:21

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Reply By: eighty matey - Sunday, Jun 05, 2011 at 21:53

Sunday, Jun 05, 2011 at 21:53

Hi Nip,

I might be the person in a previous thread that said it didn't make much difference to my 80 series fuel consumption.

In our experience we usually average about 14 litres per 100 km, definitely under 15l/100km. That's highway, dirt road, low range. The wagon has all food, water, fridge, recovery gear, bull bar up front, two wheels hanging off a bar on the back, the lot.

The 80 is non turbo and we probably average about 90km/hr on bitumen. I make a point of not pushing it for a number of reasons, including fuel economy.

Our roof top tent is a Shipp Shape, which is larger in area than most other tents but it probably has about the same profile as others when considering wind resistance.

I reckon we get better fuel economy with the tent on top than if we were towing a trailer and we have more room inside the wagon than we would if we were tenting it. All our bedding stays up top for a start.

They're quick to set up, as it takes about five minutes from unclipping the cover to pegging down the awning (which is the cover as well). We are really happy with the rooftop tent and it doesn't cost us more than 1 litre per 100 km by our figures

Have fun,

eighty matey

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Follow Up By: Member - Nip (QLD) - Sunday, Jun 05, 2011 at 22:29

Sunday, Jun 05, 2011 at 22:29

Hi Eighty Matey,

Yes, it was your post that had the details on fuel consumption and it was a bit heartening to hear that you didn't notice much difference, since they do look like a fair windbreak stuck up on top.

I had an Aussie Swag camper for a number of years and the first year I had the 100 series (had a turbo diesel Rodeo before that) I did one run fishing up into the territory (about 600km round trip) and averaged about 20lt/100k (camper/boat all fuel/water etc for 2 weeks). Turbo-ed it as soon as I got back in disgust since I could take slow, but not slow and thirsty. The next time I did that trip (2 years later) with the same gear I got about 15-16 lt/100km and I could actually sit on a reasonable speed as well.

Sold the camper and have only had a tent again. Now, while the OzTent is good, I think there's lots of advantages in this roof top idea with having your bedding and stuff already set up and ready to go (like in the camper). My biggest concern was that it'd belt the economy around a heap. From your comments and from Mick and Dave's it's all sounding pretty good. Only thing now is which one to buy and remembering not to drive in under the supermarket if I put one on!

Cheers Nip

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Follow Up By: Member - Nip (QLD) - Monday, Jun 06, 2011 at 07:21

Monday, Jun 06, 2011 at 07:21

Bit of an error in this last follow-up. The run up to the Gulf is about a 6000km trip - be like something from Dr Who to do it in 600km!

Cheers Nip

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Reply By: Richard W (NSW) - Monday, Jun 06, 2011 at 06:51

Monday, Jun 06, 2011 at 06:51

Nip,

Whilst I don't have a rooftop tent I usually have a roofrack loaded with a spare tyre and a few other things. I have compared consumption with the rare times I don't have the roofrack on and it does make a bit of a difference particularly in a strong headwind. As you said I have found the fuel consumption increases significantly once speed is increased over 100KPH. BTW my vehicle is a TD100 Auto.

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Follow Up By: Member - Nip (QLD) - Monday, Jun 06, 2011 at 07:26

Monday, Jun 06, 2011 at 07:26

Thanks Richard.

Now I've got a few non-negative comments, I'll have to get serious in choosing which one to buy since there are quite a number of brands. I'll head down to the camping show in Briso this weekend and roll around in some.

Nip

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Reply By: Member - Pedro the One - Tuesday, Jun 07, 2011 at 13:37

Tuesday, Jun 07, 2011 at 13:37

Hi, Nip:
I'll also go along with the majority of comments here ....... I have a RoofTop Tent on my Troopy ('92 1HZ75) and my consumption, generally, is about the same with it as without it fitted.

Obviously, Troopy's have the aerodynamics of a large Besser brick on wheels but the price is a very slight increase in fuel only. I also, generally, limit my speed to around 90 kmh - any inadvertant creep towards 100 triggers me to drop it back. However, on bitumen, even 100 - 110 she travels smoothly , albeit at the slight fuel increase. Again, generally, my travelling (as a gold prospector!) is frequently longer distances and over 'rat-spit' tracks where fuel consumption is simply the price to pay.

These are really great, with an 8' x 4' bed area - that is so dool at the end of the day, believe me!!

BUT: Those lucky blokes that can 'whip them up inside five minutes' REALLY have my admiration ?????
I allow fifteen minutes - a leisurely set-up. Then again, mine is on a Troopy ........ quite high and I do carry a smallee ladder to 'ease trhe pain..'.

I love 'em BUT mine is up for sale as I now have a TENTCOT, more suiteable for my travelling style as a solo prospector -
SHMBO is fearful of the 'dreaded pointed finger' when ascending the Rooftop !!!! ........ because of a previous inadvertantly conceived 'incident' !!
Thusly, I am now able to travel 'solo ............. thank you, God !!

TIP !! Make sure your access ladder has FLAT rungs, not TUBULAR !!
These play merry hell with your insteps ...................

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