Trailer vs RocketBox

[RKBA]

Anyone who claims that the jumbo rooftop carriers don't dramatically impact fuel economy either don't really check their mileage or have a hard time telling the truth.

The aero drag on the roof with those larger boxes is SIGNIFICANT and WILL drastically decrease mpg as well as make a lifted XJ loads of fun to drive on windy days. I have no experience with the low profile Yakima boxes, they may be a reasonable compromise, but do they hold enough crap to bother with? They don't look like it to me.

My suggestion would depend on how much crap you are carrying. if you can fit it in a rooftop sized box and like to drive extra-legal speeds, then a rear mount hitch-haul (with a box) is the way to go. It will block hatch access, but you don't take the mpg hit and can get to the stuff easier.

Personally I believe a 4x8 medium duty utility trailer is one of the best Jeep accessories ever made. It makes any bobtail 4x4 the cargo equal of a one ton truck whenever you need it. Another slick little set up would be to drop a used Sears cargo box on one of those little red Chinese 48" trailers that Harbor Freight sells for $149. Guys with motorcycles can tow that so I doubt it weighs more than four hundred pounds fully loaded.

As someone else mentioned, state laws and good sense dictate that you drive a little slower when towing. In my experience towing trailers with low frontal area, the slightly lower speed makes the towing mpg hit almost nil. My pop-up weighs in at ~1500 lbs camping weight and my XJ has 32s/4.56s/AW4. If I drive 70 when unladen, I get right on 18-19 mpg. When towing the Jayco and keeping it at 65 or under, the XJ will give me 17-18 pretty consistently on the flats and 15-17 in the hills.

 

[muduck18]

Now that things are correct:
I still feel sorry for your dog, mine likes to ride in jeeps and mine likes to move around.
My jeep gets 500 to 1000 miles a week, my wife drives it to work and I drive it all over the place on the weekends.
I have four rack setups for the roof.
-canue rack
-cargo rack
-bike rack
-light rack/bar
all of which have over 3,000 miles of hwy driving (not all at at the same time individually)

I think its safe to say that i might know a thing or two about putting stuff on top of my jeep and how it would affect my gas mileage.
trailer it or back porch it.

Lets get a few things correct:
My dog has never ridden in my jeep. My point was that a dog does not need the entire jeep to "roam around" in. It need enough room to lay down and have water and air.

My jeep has almost nothing on the roof, and only gets driven to the trail and back. My gas mileage with 33's/aw4/4.88's is about the same as yours.

A canoe is not stream line without a cover (it is open on the top or bottom which has a huge impact on aerodynamics). A rocket box IS streamline and much more aerodynamic.


Michael

 

[Jeffro600]

In most, if not all states, the towing speed is much lower than the normal speed limit. Here in California it 55 mph, for towing, compared to speed limits up to 70 mph. Some states have a 75-mph speed limit. On a cross-country trip, it would be a PIA to go so slow IMO.
How much is your time worth?
"I can't drive 55"---Sammy Hagar

I tow quite regularly through CA...ive NEVER seen anyone follow the 55 with a trailer speed limit, nor have i ever seen it enforced.

As a matter of fact, last year i got pulled over while towing a trailer behind my car...i was doing every bit of 75-80 and i got pulled over for a light that broke off the trailer and was dragging...didnt say anything about how fast i was going. If your going 70 or anything less than 80 on any freeway in CA, your gettin ran over!

 

[Bones]

I have run both a trailer and a large roof top box at various times.

Each has its pros and cons.



The box is OK. Mine isn't as aerodynamic as a rocket box and I see a significant MPG loss at highway speeds. Running around town I don't think it hampers things much. I do think it adds a significant amount of stress on the body/roof when it is loaded, especially on the trail. I actually broke a Yakima gutter mount this year when I hit a wash on a BIA road in NM. Had it been a problem with the trailer I would have had the option of dropping it and getting parts. With the roof box I had to try and support the box and limp about a hundred miles into Durango to find a new mount. The box is much more civil in town. You don't have to worry about it as you would a trailer when getting in and out of parking lots and on busy city streets (though it keeps you out of the same parking garages a trailer would).

My favorite is the trailer. It tows like it isn't there, hauls more, and for me costs less in terms of fuel consumption on the highway. It has its disadvantages when it comes to some trails, in town maneuverability, and parking. It hampers access to things in the back of the Jeep since the swing arm won’t open when the trailer is hooked up and it slows me down on some trails because it tends to bounce on the rough terrain, not enough to destroy itself, but it can make a mess of things within (especially in a cooler). The major advantage is that it can be disconnected and left at camp in most situations. The trailer is much easier to get things in and out of than the roof box (a big plus for the rest of the family) and causes less overall stress to the Jeep.

For a cross country trip I would consider the things I plan on doing. If you aren’t going to be running trails and you will be in urban situations a lot I would do a low profile roof box. If your trip is just to get from A to B down the highway, you are planning a lot of off-road adventures where a trailer could be left at the trail head and picked up on the way out, or base camping and exploring, I would do the trailer.

Bones :skull1:

 

[Gojeep]

I concur with above as have spent 5 years using each in the Outback of Austraila totally over a 50,000 kms with each. I noticed very little difference in MPG between both in the end over each 12,000 kms trip.
Some long tern effect with having the full length rack was fatigue in the body as got cracking in all the door openings and had to fully seam weld them to prevent them further. Also roll the Jeep with this setup which may not have happened without the higher COG. Also you are carring al your weight over the 4 wheels only with no quick way to remove it.
With that Jeep written off I switched to another XJ and tow a trailer now instead. Some amount of time now and no cracking has appeared in the door openings showing it was the rack that caused it. I now have my weight ( the total is more of course )spread over 6 wheels and can drop that weight to get out of a bog in an instant and then tow the trailer out with a strap once out. So I find this setup the best for me and wont be going back to the rook rack.

Hope that helps someone and if you want more information on my offroad trailer running XJ suspension and shocks, see my site. www.go.jeep-xj.info

 

[natep1]

I run one of the cheap 4ft x 4ft Harbor Freight trailer (I paid less than $110 for it) with an old uhaul cartop carrier on it. You don't notice it back there and the mpg impact is negligable.

 

[jmsull]

Thanks Bones and Gojeep. You guys have both given me some very good points to consider. Gojeep I've run across a few different threads aout your rig and I've seen the mag article, you have certainly set the bar in terms of this whole endeavor.

I'll be a little more specific;

on Wed, Oct 12th, I'll be leaving from Chicago to drive to the middle of northern Nevada to visit friends. It will be a straight shot on I-80, a good 1500mi. I plan to stay through the weekend. Then I'll be heading up to Yellowstone/Grand Teton area, and do some camping for the rest of the week. I plan to start heading home on friday and be home saturday.

So lots of pure interstate highway driving, then camping in a national park.

I just got a 4x8 trailer and I have a RocketBox, so either is an option although I still don't have the trailer wiring on the trailer or the jeep, so I'll have to do that before I go.

 

[Gojeep]

If you are doing a lot of interstate, then I would go the trailer, as once you get mass into momentum it takes less power to keep it there. So a trailer is good under these circumstanses as you wont be pulling from a stand still so often. Where as once up to speed, aerodynamics plays a much bigger roll on fuel mileage the faster you go and not so much at slower speeds and none really at all at crawling speeds.

Hope that helps

 

[willys64]

Okay, so I'm one of those guys that pulls the little 48" trailer with a motorcycle. I haven't noticed any change in milage with my 1987 Goldwing 1200. If your going to be pulling a 4x8 or 5x8 trailer around behind you, I would suggest that you go ahead and mount your rocket box to the front of it, then use the extra space behind the rocket box for your spare tire, cooler, and anything else that can be lashed down. That way if you plan on taking a little day trip and still want to take some extra stuff with you, you can always put the rocket box on the Jeep.

 

[Shogun]

Some trailer details;

First off, I wouldn't give harbor fright a nickel of my money, buts thats a personal/political thing. The facts are, if its harbor fright, it will break.

Here in the Arizona Territories I see alot of trailers on the side of the road, broken wheels, bearings, flats, axles etc. I decided that wouldnt happen to me, buy it once, buy it right. I want a trailer engineered for durability and off-road use.

That means (just about) only one source; military. When I was trained on the M151/M416 I was told to just forget the trailer was there. Thats how tough it is, when you get out, it will be there. M416s are getting tough to find, but theres a bunch of Canadian ones on the market now if you can get up north. Light enough to pick up empty and move around, and they float at rated GW. Only extra might be slightly upgraded springs since its easy to overload them.

 

[Shogun]

Some trailer details;

First off, I wouldn't give harbor fright a nickel of my money, buts thats a personal/political thing. The facts are, if its harbor fright, it will break.

Here in the Arizona Territories I see alot of trailers on the side of the road, broken wheels, bearings, flats, axles etc. I decided that wouldnt happen to me, buy it once, buy it right. I want a trailer engineered for durability and off-road use.

That means (just about) only one source; military. When I was trained on the M151/M416 I was told to just forget the trailer was there. Thats how tough it is, when you get out, it will be there. M416s are getting tough to find, but theres a bunch of Canadian ones on the market now if you can get up north. Light enough to pick up empty and move around, and they float at rated GW. Only extra might be slightly upgraded springs since its easy to overload them.

Oh yea, please dont convert the hitch to those urban trucker, U Haul, ball type things. Do it right, get a pintle, you'll appreciate the strength and angle capability.

 

[Bones]

Oh yea, please dont convert the hitch to those urban trucker, U Haul, ball type things. Do it right, get a pintle, you'll appreciate the strength and angle capability.

I'm not one to believe the pintle is the only way to go. My trailer is a BT-3C and as such came with a factory 1 7/8" ball type hitch. Keeping to rated weight (1K for the BT-3C/ and 500 lbs for the military versions if you want them to float) a quality ball and quality hitch are more than strong enough and the ball doesn't rattle as the pintle set up does. The angle capability is more than adequate with the 1 7/8" ball set up on my trailer. It's been over many of CO's trails including old Tincup and Pearl, with no binding at all.

Bones :skull1:

 

[Gojeep]

If you want un-hinded movement and dead quite and absorbtion of any vibes between the vehicle and trailer you should use what all good Aussie trailers do.

I show how to make your own if you want on my site.
They even sell them in the States now. http://www.adventuretrailers.com/Horizon/Horizon_Features/HorizonFeatures.html