Offroad trailer Vs Roof tent MPG

DrMoab

Explorer
I'm curious if there is anyone else who has moved a tent from the roof of their vehicle to a trailer and what the MPG difference was.

I know when I take the tent off my roof I gain around 2 MPG. For awhile now I've been thinking that pulling a trailer would really cause my MPG to suffer but now I'm not too sure.

Anyone else put any thought into this or possibly compared the difference?
 

Honu

lost on the mainland
I know towing my conqueror conquest (larger than the compacts)

I dropped about 2-4 MPG depending on terrain etc..

never had a RTT and always had a rack on top so hope that helps some :)
 

JIMBO

Expedition Leader
:sombrero:Not factual, but according to the OBC (on board computer), I lose .5 mpg when pulling the trailer on--LEVEL FREEWAY !!

:costumed-smiley-007:costumed-smiley-007 JIMBO
 

kai38

Explorer
I have a Australian Land Cruiser magazine that did a comparison, tent on the roof or on the trailer. The MPG were worse with the tent on the roof.
Mileage wasn't that much different from no RTT then towing a small trailer with the tent mount on it.
My tent is mounted on my M416, even over loaded I don't feel it back there and last trip my MPG were 17.75 MPG with 22.5 the best. That was driving 55-60 mph though. At my usual speed of 75-80 I get about 15-16 mpg.
 

gasman

Adventurer
prolly not gonna make a big difference unless your travellin a lot of miles. with the trailer now, you just bring more stuff so the weight factor puts your mileage back up .. now if your gonna have that tent on the roof all year long , that might be another story..
 

Martyn

Supporting Sponsor, Overland Certified OC0018
There is at least on large thread that has been posted in the past on this subject, if you do a search you should find it.

To summarize a trailer that is within the slipstream of the tow vehicle reduces your mpg by less than a roof top tent.
 

Sirocco

Explorer
To summarize a trailer that is within the slipstream of the tow vehicle reduces your mpg by less than a roof top tent.

Thats good news then, because I am soon to buy a trailer and mount my Maggi on it instead of the roof :ylsmoke:

G
 
S

Street Wolf

Guest
I didn't really notice any real loss when I put my RTT on the Disco.
 

cnynrat

Expedition Leader
I can't comment directly on the comparison the OP is looking for as I never had an RTT mounted on my roof. I can tell you that towing an AT Horizon I'm down about 2-3 MPG on the highway depending on road and traffic conditions. Not surpisingly, big hills seem to do the most damage.
 

R_Lefebvre

Expedition Leader
I didn't really notice any real loss when I put my RTT on the Disco.

That's because you already had a massive rack up there that was already sucking the gas. The tent hardly made a difference to the slipstream at all compared to the big rack.

I know a lot of the big rack guys don't believe it, but smallish trailers really do have a minimal effect, seemingly about equivalent to a roof rack. But then with the trailer you have SO much more capacity. I specifically designed my trailer to be in my slipstream, and it seems to work. Even with it's quite large size and weight, I'm also getting the ~2-3 mpg hit on milage. That's not a lot compared to what I'm gaining by having it.

For me, there's no question about which is the more logical choice. Trailers give you much more cubic feet capacity, another axle to take the weight, keep the CG lower on the truck, all that, and they don't take any more fuel to tow than a big rack. There's the side benefits of being able to easily drop the trailer if needed. Whether you want to shed the load because of a stuck, or because you want to leave your camping gear behind so you can run a trail unecumbered.

I believe it was Tom Sheppard who said that the big racks are illogical, and people are really only doing it for the "serious explorer look".
 

Martyn

Supporting Sponsor, Overland Certified OC0018
I can't comment directly on the comparison the OP is looking for as I never had an RTT mounted on my roof. I can tell you that towing an AT Horizon I'm down about 2-3 MPG on the highway depending on road and traffic conditions. Not surpisingly, big hills seem to do the most damage.

A RTT increases wind resistance all the time, slow, fast, uphill, downhill ,so the loss in mpg occurs all the time.

A trailer riding in the slipstream will decrease mpg primarily when you go uphill or when you are accelerating to driving speeds. Once you reach a consistent speed the decrease is minimal and is due to increased mass and the rolling resistance of the tires.

Going down hill it actually puts fuel back into you tank (or so it says on all of our sales literature) :sombrero:
 

R_Lefebvre

Expedition Leader
A RTT increases wind resistance all the time, slow, fast, uphill, downhill ,so the loss in mpg occurs all the time.

A trailer riding in the slipstream will decrease mpg primarily when you go uphill or when you are accelerating to driving speeds. Once you reach a consistent speed the decrease is minimal and is due to increased mass and the rolling resistance of the tires.

Going down hill it actually puts fuel back into you tank (or so it says on all of our sales literature) :sombrero:

That's partially true. It depends a lot on how you go up the hill. If you put the hammer down and charge up the hill with a trailer, you'll never gain the fuel back. The key to good milage is to take it easy going up hills. If you try to hold your speed, and the engine goes into open loop where the fuel/air ratio goes from 14.7:1 to maybe 13:1 or worse, spark timing is retarded, and the transmission kicks down a gear or two, you waste a lot of gas getting up the hill, and you'll never make it up on the backside.

The same is true with an RTT, but I think to a much less effect when talking about hills specifically. Since they weigh so much less than a trailer, they have less effect going up hills.

So, when I'm trying to supermilage with the trailer, I really let it slow down going up hills. I have a Scangauge, so I keep an eye on the open/closed loop status. I will let it slow down within reason, to keep it in closed loop if possible. I will also preferentially kick it down into 3rd gear manually if required. I'd rather be down a gear, than go Wide Open Throttle. Basically, after about 1/2 throttle, you're pouring the coals to it, and Brake Specific Fuel Consumption goes to ****.

If you're in an area with rolling hills, I like to build up a head of steam on the backside, and then "coast" up the next hill. I'll exceed the speed limit within reason, building speed with the throttle less than 1/2 way, so that I can climb the next hill at less than 1/2 throttle, bleeding off speed.

Obviously this all takes some extra effort, but it pays off.
 

Martyn

Supporting Sponsor, Overland Certified OC0018
That's partially true. It depends a lot on how you go up the hill. If you put the hammer down and charge up the hill with a trailer, you'll never gain the fuel back. The key to good milage is to take it easy going up hills. If you try to hold your speed, and the engine goes into open loop where the fuel/air ratio goes from 14.7:1 to maybe 13:1 or worse, spark timing is retarded, and the transmission kicks down a gear or two, you waste a lot of gas getting up the hill, and you'll never make it up on the backside.

The same is true with an RTT, but I think to a much less effect when talking about hills specifically. Since they weigh so much less than a trailer, they have less effect going up hills.

So, when I'm trying to supermilage with the trailer, I really let it slow down going up hills. I have a Scangauge, so I keep an eye on the open/closed loop status. I will let it slow down within reason, to keep it in closed loop if possible. I will also preferentially kick it down into 3rd gear manually if required. I'd rather be down a gear, than go Wide Open Throttle. Basically, after about 1/2 throttle, you're pouring the coals to it, and Brake Specific Fuel Consumption goes to ****.

If you're in an area with rolling hills, I like to build up a head of steam on the backside, and then "coast" up the next hill. I'll exceed the speed limit within reason, building speed with the throttle less than 1/2 way, so that I can climb the next hill at less than 1/2 throttle, bleeding off speed.

Obviously this all takes some extra effort, but it pays off.

Rob

Very sensible driving tips, thank you for sharing that with everyone.
 

DrMoab

Explorer
Thanks for the input guys.

The angle I got from this thread that I didn't think about before was the fact that right now, my tent resides on my roof all the time. This isn't my daily driver but I do a lot of day trips out on the desert where I don't need a tent (or a trailer)

Obviously the benefits are greater if for nothing else, the fact that I won't be dragging the trailer around every time I go some place.
 

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