Roof racks and loading...

[Mike S]

Tom Sheppard's article - Loading and Lashing: Controlling and organizing cargo for maximum safety and efficiency - in the latest edition of Overland Journal was exemplary. Excellent article, Tom.

He takes on the roof rack in the perspective required IMHO. Because we sell tents that are mounted on roof racks, we have this discussion fairly frequenty, and we are conservative.

Many of us forget that vehicle roof load limits are DYNAMIC limits - we should not ignore what they tell us about handling, braking and other effects of a higher CG in our vehicles. If a Landcruiser (or LR or whatever) has a published weight limit of 165 lbs. with a Thule, Yakima, or other rack system one should heed this specification. Adding more bars increases the strength and distributes weight better, but does NOT increase the carrying capacity. I have seen roof racks that come close to 165 lbs. - before being loaded - loaded with gas cans, firewood, etc. that far exceeds the rated limit.

Next question I ask about roof loading specifications is, "Under what conditions does the spec apply?" Highway? Rock crawling? Pounding down a corduroy road in Baja at 35 mph.? Think about your CG on a sidehill when you drop a wheel. Or 250 lbs. pounding on a couple square inches of rain gutter.

During these discussions I like to apply the deer test - "If you are traveling a paved mountain road and driving a long downhill curve at 50 mph in rain or snow, and a deer jumps into the road, can you control your vehicle while avoiding a potential venison burger event?"

Modern vehicles are engineered to withstand a roll-over and the roofs are strong - but static roof load limits are seldom, if ever, published. I think this is because the manufacturers do not want to encourage overloading. A occupied roof tent? No problem on any vehicle we have fitted so far. But we tell people not to drive around with the tent deployed - let alone occupied.

To quote Tom's article, "Just keep it aerodynamically smooth, keep it low, keep the load light - sleeping bags, that kind of thing."

What are your thoughts? Are you more aggressive, or more conservative?

 

[HMR]

Always a good topic.


:lurk:

 

[Streakerfreak]

I try to be as conservative as possible, even with two sea kayaks.

The wieght of the kayaks and two gas cans come to about 160pounds. Is it perfect? No of course not, but there is not much of a choice. The two kayaks are as close to center as possble which helps deal with the bad CG.

If I do not need the kayaks, they come off and I will only carry gas cans up there. There is plenty of room in the bed and truck box for firewood and all our other supplies.

I have always been scared about overloading roofs as I have seen a few bad incidents from overloading.

Gas cans will always go on the canopy for me. I have had too many accidents with gas cans in the bed and with the canopy the fumes were extremely volatile.

 

[Martinjmpr]

IMO a roof rack should be the last resort for storage, for the reasons you mentioned: CG, dynamic loads, wear and tear on the gutters or mounts, etc. Clothing, sleeping bags, and anything else that's bulky but light.

I cringe whenever I see gas or water cans on a roof rack. Asking for trouble, I think. Ditto for a high-lift. I'd mount that stuff as low as possible. Oversized spare tires also seem inadvisable. Obviously, there are some circumstances where loading up the roof rack is a neccessity, but it should be avoided/minimized if at all possible.

 

[Scott Brady]

I am extremely conservative with roof loads, and have not run a rack on a vehicle for many years (except to carry a kayak). I prefer to use a trailer with the roof tent, toys, etc.

Light loads are fine and there are times when a roof rack is unavoidable, like if you have two kids and no trailer. However, that will require a more conservative approach to road speeds and trail difficulty.

A roof tent with associated mounting brackets would be about the limit I would recommend, especially on a tall, coil-sprung vehicle.

In most cases I see really bad weight distribution packing when people use roof racks. They put 400 pounds of fuel and water on the roof and all of their light bedding and clothes inside? It needs to be reversed. Buy a high-quality fuel and water can and mount them as close to the midline of the vehicle and as low as physically possible. Of course, an aux tank at the frame level is the ultimate.

 

[articulate]

Tom Sheppard's article - Loading and Lashing: Controlling and organizing cargo for maximum safety and efficiency - in the latest edition of Overland Journal was exemplary.

That article was brilliant. I learned a lot from that one, and cracked up several times. (Oh God, the caption to the photo of the Defender plopped over on the sand dune was hysterical. "Just a tad late on reading the terrain there, Hoskins." Something like that.)

Anyway, since reading that piece, I've been looking at our truck and locating the load deficiencies that I have: heavy rear bumper behind the axle, crossover tool box is in prime territory (right in between the axles) for the heaviest items, and a few others.

I just installed a pair of Yak load bars on the roof, too. A griping Englishman in my head the whole time. The only thing I intended for the bars is an awning. I may have to be reminded of that from time to time.

A trailer is more and more appealing all the time.

 

[DaveInDenver]

A trailer is more and more appealing all the time.

Easy for you to say, what with your fancy V6 and triple digit horsepower. Just count me in the disinterested ambivalence crowd on the trailer subject. I think everyone needs to try touring with a 4 cylinder 4WD vehicle, then they might see the less is more ideal. Oh dear, how will I ever survive on 10 gallons of water, a paper map and no on-board shower?

 

[Mobryan]

Mine is currently a 'yak & bike affair, though I probably will start needing to load more up there in a month (less actually ) when mini-me arrives.

I'm in a little better situation then most, though. I have no aerodynamics to ruin, and 150-200lbs is a drop in the bucket, compartively.


Matt

edit for spelling.

 

[stevenmd]

With a family the size of 6 (Suzi & I with 4 kids...:sombrero: ) I usually have to put stuff on the roof. But I limit that type of travel to paved and fireroads. If I am traveling offroad, it is usually only my wife, daughter & I or the boys & I. Because of this, I am saving up for an offroad trailer so we can all go together... because, dang it, I refuse to buy a mini-van.

 

[Mike S]

...I think everyone needs to try touring with a 4 cylinder 4WD vehicle, then they might see the less is more ideal. Oh dear, how will I ever survive on 10 gallons of water, a paper map and no on-board shower?

Dave, I have an old '47 CJ2A that has a throbbing 60 HP under the hood and more zerk fittings than any 6 modern trucks. GVW is something like 2200 pounds. 5.38 gearing and three on the floor. This forces the same type of religious consideration of loads as a motorcycle - many of which have more horsepower. But it has a trialer hitch!

 

[R_Lefebvre]

Good topic of discussion. It should be pointed out that as soon as you lift a vehicle, the OEM roof load limits just got thrown out the window.

One of my friends is a vehicle dynamics engineer for an OEM. He's one of the guys who figures out when these things will tip. He has implored me not to lift my truck. At all. And roof loads are a no-no.

Obviously, that's the ultra conservative engineering point of view. The rest of us have to take calculated risks. But, the combination or suspension lift and roof loads should be given extra consideration.

Heavy duty springs and shocks will always help the situation. But then disconnected swaybars hurt it again.

 

[DaveInDenver]

Dave, I have an old '47 CJ2A that has a throbbing 60 HP under the hood and more zerk fittings than any 6 modern trucks. GVW is something like 2200 pounds. 5.38 gearing and three on the floor. This forces the same type of religious consideration of loads as a motorcycle - many of which have more horsepower. But it has a trialer hitch!

My old junk has a trailer hitch, but hook a 1,000 trailer to it and I'm crawling up hill. It's just the way it is when everything starts at 6,000 ft, you have a 5,000 lbs truck with 125 HP (at sea level) and goes up up up! But I could live with that, it's off road where I'd be struggling. I have enough trouble keeping my truck moving without killing it... Even if I had a ton of power, I just don't see a trailer as who we are. We had a little Apache pop-up years ago and both of us just could never get in sync with it. We like not having a particular destination in mind and just popping the 'Nest open when we get there. Low impact, minimal footprint, simple. Like I say, just disinterested, but to each his own.

 

[upcruiser]

Shepard's article had me thinking a bunch too regarding my configuration. My biggest constraints are really my in-vehicle sleeping arrangement and my need to haul things on the roof like bikes, canoes, and kayaks thus negating the ability to run a rooftop tent. I could however still get my roof weight down a ton more though. In an effort to keep overall vehicle weight down and save $ I went with hauling my spare (although it is a 33x9.50 vs 12.50 on aluminum wheel) on the roof along with my highlift, shovel, and at times, extra fuel and water. My next quest is probably going to be getting a rear bumper to take the jerry cans, spare, and highlift at least. That might allow me to loose the basket which is a heavy pig then just run some Thule load bars for the boats. My other big motivation for all of this is fuel economy and reducing drag would go along way towards improving on-highway performance of the FJ80.

 

[astateofmike]

I have always been conservative with my loading. I have a full length roof rack on my RRC and I know that the rack can hold my weight plus a 32 inch tire.....but that was me loading and lashing, not driving.

And I know that I can take about a 30° side slope, with the 65lb tire on the rack, slow and even, without going over. (15° is where I get careful and the wife will swear at me).

So, I have 2 Tent Cots, at about 65 lbs together, plus bedding I carry up top. Everything else goes inside. I am working on a rear tire carrier idea with room for gas cans (as my RRClassic has like a 16 gallon tank, and 12 mpg tops). Until then, I limit the roads I travel and have a trailer hitch mounted carrier for gas and water, tire inside and the bulky, but light weight stuff on the roof..

Works ok, but sometimes I wish I had something bigger with more ponies.

 

[madizell]

My old junk has a trailer hitch, but hook a 1,000 trailer to it and I'm crawling up hill. It's just the way it is when everything starts at 6,000 ft, you have a 5,000 lbs truck with 125 HP (at sea level) and goes up up up! But I could live with that, it's off road where I'd be struggling. I have enough trouble keeping my truck moving without killing it... Even if I had a ton of power, I just don't see a trailer as who we are. We had a little Apache pop-up years ago and both of us just could never get in sync with it. We like not having a particular destination in mind and just popping the 'Nest open when we get there. Low impact, minimal footprint, simple. Like I say, just disinterested, but to each his own.

Well, let's see...CJ-7 with 2.5L 4 cyl and maybe 90hp, running TSL 33's, BW T-4, carbureted, etc. Power? Not. But on one occasion I towed a companion Jeep out of Squaw Creek trail in Alaska over snow and ice for 4 miles to trail head, and on another towed a built YJ for about 12 miles down off of the Talkeetnas and into Willow after the YJ blew its auto transmisison. Each vehicle was well over the rated tow limits for an '85 CJ-7 and far beyond the power ability of the engine, but I had no problems either time. Could it have pulled a 1,500 pound trailer on the same terrain? Don't see why not.

During WWII, the equivalent of the CJ2A pulled many a trailer weighing 1,000 pounds empty and 2,000 to 3,000 pounds loaded over uncertain terrain using skinny tires and bad gas. Rated to carry only 500 pounds of payload, they regularly carried 2 times that and more. Horsepower and displacement are over-rated. I like power, certainly, but my old CJ2A with only 65hp at best climbed everything in front of it, carried heavy loads on occasion, and never ran completely out of poop. All you need is patience.