Jerry can directly on the roof -- ok to proceed?

[kty]

I'm headed to a remote area (West Texas) and will need some extra fuel for peace of mind. I have an OEM roof rack with a Thule box mounted. My plan is to place a 5 gallon plastic jerry can (scepter) in the corner of a cross and side bar, sitting directly on the roof, and to use 2 tie down straps to secure it (one vert, one horiz). The fuel will weigh approx 30 pounds.

Any reason this might be a bad idea?

 

[Kinnada]

I'm headed to a remote area (West Texas) and will need some extra fuel for peace of mind. I have an OEM roof rack with a Thule box mounted. My plan is to place a 5 gallon plastic jerry can (scepter) in the corner of a cross and side bar, sitting directly on the roof, and to use 2 tie down straps to secure it (one vert, one horiz). The fuel will weigh approx 30 pounds.

Any reason this might be a bad idea?

i've had to do this with a metal nato can at the beach and it's a little sketchy. first off is the bulkiness of it damaging the roof, the fear of it detaching in a collision, and the heat definitely expands it. my seals leaked a little bit and made everything stink. read up on your model and see what's recommended for expansion when filling it up.

 

[bigredmachine]

i would want to put something under the can to prevent it from scratching the roof. i dont think the weigh will be too much of an issue but i would empty the can once i got below 3/4 tank just so im not carrying the full can around

 

[kty]

i've had to do this with a metal nato can at the beach and it's a little sketchy. first off is the bulkiness of it damaging the roof, the fear of it detaching in a collision, and the heat definitely expands it. my seals leaked a little bit and made everything stink. read up on your model and see what's recommended for expansion when filling it up.

I was originally thinking I'd get some high quality metal NATO cans, but I think they'll be heavier and probably very noisy. So now I'm just looking at something along these lines: https://www.amazon.com/gp/product/B08W7VY3BP/ref=ox_sc_act_title_2?smid=ATVPDKIKX0DER&th=1

 

[Kinnada]

I was originally thinking I'd get some high quality metal NATO cans, but I think they'll be heavier and probably very noisy. So now I'm just looking at something along these lines: https://www.amazon.com/gp/product/B08W7VY3BP/ref=ox_sc_act_title_2?smid=ATVPDKIKX0DER&th=1

i love my wavian metal cans they are tough as hell. not noisy at all. you gotta keep fresh seals on hand because they do dry rot pretty quick. i'll likely never put those cans on roof again tho- too sketchy. that's a big reason i got an old ammo trailer to haul my fuel.
i can't speak to the plastic ones. good luck man

 

[Sandroad]

I think I’ve seen @linuxgod carrying fuel on the roof. Maybe he’ll weigh in.

 

[clrussell]

You’ll be fine.

Fill them when you get close to no fuel destination, empty them when you can.

Put something under it

 

[Gazziza]

How big is the Thule box? While I have an LRA tank I will also use Armadillo bags and just throw them into my Thule box up top.

Armadillo Liquid Reservoir Bag 3 Gal

Flexible, collapsible, lightweight, expedition-ready utility bladders for the safe transport and storage of liquid hydrocarbon products and other powersports and automotive fluidsConveniently transports essential automotive and powersports fluidsWeighs a

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Armadillo Liquid Reservoir Bag 5 Gal

Flexible, collapsible, lightweight, expedition-ready utility bladders for the safe transport and storage of liquid hydrocarbon products and other powersports and automotive fluidsConveniently transports essential automotive and powersports fluidsWeighs a

www.happy-trail.com

 

[rherrco]

I was originally thinking I'd get some high quality metal NATO cans, but I think they'll be heavier and probably very noisy. So now I'm just looking at something along these lines: https://www.amazon.com/gp/product/B08W7VY3BP/ref=ox_sc_act_title_2?smid=ATVPDKIKX0DER&th=1

I used some foam rubber on one side of the gas can to keep it level on the roof. But what ever you use to tie it down, double it for the sake of your peace of mind.

 

[Valgrind]

I think this sounds a little sketchy personally. I really don't like taking a chance with fuel. I def needed my extra gas going to west texas too.

Granted I have a roof rack, not sure how well this would work with a stock rack. I use these front runner mounts with metal jerry cans, they are mounted extremely stout. I feel confident if there ever was an accident.

https://www.frontrunneroutfitters.com/en/us/single-jerry-can-holder.html

Def buy a legit metal jerry can if you get one. It will last much longer than plastic, will not degrade in the sun etc.

 

[Sandroad]

Others have used these I think.

RotopaX | The Worlds Toughest Mountable Container System

Home of the worlds toughest overland, offroad, accessory fuel containers, water containers, and mounting hardware. Rotationally molded for unrivaled strength with multiple mounting options available. Find the perfect fuel container for any adventure.

www.rotopax.com

 

[sdnative]

There's a few examples of people on here mounting 4gal Rotopax on the factory rack. @TeCKis300 is one of them IIRC. I would never let anything rest directly on the body metal / paint though, if that is what you are considering.

 

[mep1811]

Great plan. Mount it close to the fuel tank fill and you can fuel up with a super syphon without any mess. Be sure to refuel only in the cool morning to prevent hot gas from spilling.

Do not try to refuel with the stock nozzle unless you want gas all over the place.

Coarse Thread Nozzle

Ai13 offers a USA-made gas can spout that will drain your 5-gallon can in just 60 seconds. Compatible with Scepter, Midwest, Briggs & Stratton gas cans.

ai13.us

Delivery Destination – EZ-POUR

Self-Priming Quick Shake Siphon Style Pump Kit, 2.5 GPM

 

[FrazzledHunter]

With the right cans and roof rack transporting gasoline on the roof is fine IMHO.

BAJA roof rack with Wavian-NATO rack mount and Wavian-NATO 20 L cans:

 

[FrazzledHunter]

I was originally thinking I'd get some high quality metal NATO cans, but I think they'll be heavier and probably very noisy. So now I'm just looking at something along these lines: https://www.amazon.com/gp/product/B08W7VY3BP/ref=ox_sc_act_title_2?smid=ATVPDKIKX0DER&th=1

I would not use plastic fuel containers for anything much less transporting them on a car roof or for overlanding. This includes the Rotopax containers. Yes I know they're popular but I wouldn't consider one. Plastic containers swell in the heat and are more prone to cracking. I don't even use/store plastic gasoline containers in my detached shed for my lawn mower. I got rid of all my plastic fuel containers a couple of decades ago. Plastic fuel containers=junk, IMHO.

 

[bloc]

Isn't the US military still using plastic fuel containers?

I keep non-ethanol fuel in a couple of the surplus scepter cans full-time and while yes they do expand, they won't leak a drop if the cap is tight. Plus, I've had these over 10 years and the seals might as well be brand new.

To answer OP: I'd put something on the roof to keep the can from trashing your paint, and seriously consider the earlier advice to double up on your tie-down methods. It may not seem like a lot of weight until you hit something that rocks the vehicle to one side quickly..

 

[TheIcemanCometh]

Any reason this might be a bad idea?

No, not one reason. Just a bunch of reasons:

1. It is sitting directly on the roof.
2. It is plastic and can leak.
3. It is plastic and can be damaged by flying road debris
4. It will be hard to secure.
5. It will move around.

My suggestion would be to invest in a trailer hitch rack and store it and other stuff. I suggest that because with a roof box mounted you will probably not be able to mount a roof rack too.

 

[gasman4u]

Wavian 20L cans are the best fuel can available. As mentioned, keep the seals in top shape but the cans will outlast you as long as you don’t let them rust somehow.

Make sure they’re secure if they have to go up top. Either with a dedicated metal carrier like @FrazzledHunter has or with a LOT of ratchet straps, tie downs, etc.

@bloc yes, the military is using plastic cans currently. Both for fuel and water. Don’t want to mix those up.

 

[linuxgod]

I think I’ve seen @linuxgod carrying fuel on the roof. Maybe he’ll weigh in.

I have a rotopax flat on my roof and it works well. I only fill it when taking long trips, I always fill with premium fuel which seems to require less venting, I vent once a day if the rotopax swells, and I empty it into the truck at the end of each trip.

A rotopax can leak if the seal or body gets compromised but they’re pretty durable. I would not run a regular jerry can on my roof except in a pinch, and in that case it would have to be upright.

 

[linuxgod]

I would not use plastic fuel containers for anything much less transporting them on a car roof or for overlanding. This includes the Rotopax containers. Yes I know they're popular but I wouldn't consider one. Plastic containers swell in the heat and are more prone to cracking. I don't even use/store plastic gasoline containers in my detached shed for my lawn mower. I got rid of all my plastic fuel containers a couple of decades ago. Plastic fuel containers=junk, IMHO.

Metal swells in the heat too. I have 3 wavian knockoff metals cans I used in Utah in 2023 and they would swell in the heat as the fuel vaporized and would compress when we’d come down from altitude just like plastic. Maybe a much heavier gauge metal would do better?

The rotopax is pretty thick and strong plastic. It will swell, but a lot less than the scepter cans