Mounting Roof Rack on channel or not?

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D40-4Life

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I got a front runner roof rack that I had mounted by the pros 2 years ago and I only just realized that they mounted it not on the channel of my D40 but a bit further in towards the middle of the roof. About 20mm away from the channel that runs along the outside each of the roof of my D40.

I was lead to believe that the strongest point for mounting anything to the roof is the channel which is much thicker there than anywhere else. That channel is where you should be drilling holes to tap into.

Can someone please give me some insight. Am I at risk of failure if I take this roof off road and / or load it up?

What has brought this up was all the controversy lately of rhino racks being mounted on car roofs using rivets and failing. Mine has not been rivereted but screwed. ie. The rail is screwed into the roof and then the feet of the rack is installed on that. The feet hold up the rack.
 
The channel is indeed the strongest area but mounting in the channel, as I did, presents a bit of a problem. The channels are mostly filled with some kind of softish body filler, no doubt to hide the joints between the roof and side panels of the bodywork. I used closed-end stainless steel nutserts (AKA rivnuts) to mount my rack but, due to the depth of that filler, it was rather difficult to get the head of the tool in there to set the nutserts. Once they were set I packed the space between the top of the rivnuts and the surface of the filler with stainless steel washers so that the clamping pressure would in fact be on the rivnuts, not the filler.

If I was doing the job again I'd put my mounts just beside the channels. That way you still benefit from the strength of the channels, without the woes.
 
The channels are mostly filled with some kind of softish body filler
Thanks for the reply OldManBeard. So your bracket would be sitting ontop of soft fill which sits on top of the strongest point of the roof, unless you do what you did.
If I was doing the job again I'd put my mounts just beside the channels. That way you still benefit from the strength of the channels, without the woes.
Your work around is probably the strongest solution, but I guess with all the youtube vids on racks coming off the roof I'll probably avoid loading my rack anywhere close to the Navs roof limit of 66Kg off road. I think this includes the roof rack. Which I think gives me only 40Kg. Enough for a awning, maxtrax and a shovel. LOL
 
.. I'll probably avoid loading my rack anywhere close to the Navs roof limit of 66Kg off road. I think this includes the roof rack. Which I think gives me only 40Kg. Enough for a awning, maxtrax and a shovel. LOL
I didn't even know the roof limit was so pathetically low. I do carry long lengths of timber or metal from time to time but when I do that it's also supported at the front by a support arm that attaches to the bullbar when I need it. Fore and aft forces are effectively controlled by having the load securely bound to the steel carry bars at the front and rear of the tray. There's only a relatively small weight on the cabin roof rack. Under normal circumstances, I only carry the rack itself, which is all aluminium and light enough that I can pick it up with one finger, the light bar and the solar panel. Anything else that needs to go on the roof or be attached to a roof rack goes onto the canopy, as we don't need any of that unless we're travelling.
 
Neither did I until I saw the Tyler Thompson youtube vid of his D23. His rooftop tent and rhino rack basically ripped off on a 4x4 track.
Wow, now I'm really glad I only have a little weight on the cabin roof. Heavy stuff can go on the canopy roof because that's strong enough that I can walk on it without having to watch where I place my feet and the rack is attached to the strongest points anyway.
 
Very few vehicles are rated to carry a reasonable weight on the roof. Some exceptions, but the maximum for road use is 75kg as a rule.

This isn't because of the strength of the vehicle, it is all about the dynamics and how a weight up high will affect the handling. Off road this is multiplied...

In short, additional weight on the roof (or above the rear canopy), isn't the best solution.
 
Very few vehicles are rated to carry a reasonable weight on the roof. Some exceptions, but the maximum for road use is 75kg as a rule.
75Kg might be a good, safe guide but, to the best of my knowledge, there's no such rule in any Australian state, but I'd like to hear from anyone who knows otherwise.

In short, additional weight on the roof (or above the rear canopy), isn't the best solution.
I couldn't agree more. It's always best to keep the centre of gravity as low as possible. So yes, it isn't the best solution but it may be the only practical one. Plenty of times having stuff on top is unavoidable but the weight should always be kept as low as possible. In my case, the only heavy item while touring will be the second spare wheel on top of the canopy, because it's not feasible for me to carry it on the rear of the canopy and there's no space left underneath.

On one trip I saw a bloke with a single cab Navara carrying 6 steel jerry cans over the cabin roof. They were supported by a frame attached to the tub, so there was no weight or stress on the roof itself, but that's quite a bit of weight to be carrying so high up. He probably could just about have fitted a long-range tank for the money he spent on the jerry cans and the support frame and that would have put the weight down low, where it should be.
 
He probably could just about have fitted a long-range tank for the money he spent on the jerry cans and the support frame and that would have put the weight down low, where it should be.

He might have already done that, and carried the extras for those super-long trips like CSR. Chance to avoid the fuel dump? I'll take it!

I have a Long Ranger tank fitted and if I know I'm going somewhere remote, I have 5 jerry cans that I fill and put in the tub. Gives me 250L total fuel. I stopped there because I'd read that the maximum amount of fuel we're allowed to have in our cars is 250L, but then discovered that this only relates to petrol. Because diesel isn't as dangerous, we don't have a limit. Except our GVM, of course.
 
Fair comment. Even if that's the case, I have to question why he put the jerry cans on top and the lighter camping gear in the tub.

Excellent point, and one that people ought to keep in mind. High weight loading affects the vehicle's stability in corners and can cause issues in cross-winds. Personally, even though we have roof bars and a rack, I put the light things up top and keep the heavy stuff down low. I prefer to put stuff that I don't use a lot, although when I'm not towing the caravan, I carry our camp chairs up there, along with Maxx Trax and a shovel (particularly if we're heading for snow territory). I do have an awning up there too, although at this moment it's been removed from the car while I work on stronger brackets.

IMG_9677_1024x683.jpg
 
I got a front runner roof rack that I had mounted by the pros 2 years ago and I only just realized that they mounted it not on the channel of my D40 but a bit further in towards the middle of the roof. About 20mm away from the channel that runs along the outside each of the roof of my D40.

I was lead to believe that the strongest point for mounting anything to the roof is the channel which is much thicker there than anywhere else. That channel is where you should be drilling holes to tap into.

Can someone please give me some insight. Am I at risk of failure if I take this roof off road and / or load it up?

What has brought this up was all the controversy lately of rhino racks being mounted on car roofs using rivets and failing. Mine has not been rivereted but screwed. ie. The rail is screwed into the roof and then the feet of the rack is installed on that. The feet hold up the rack.
He might have already done that, and carried the extras for those super-long trips like CSR. Chance to avoid the fuel dump? I'll take it!

I have a Long Ranger tank fitted and if I know I'm going somewhere remote, I have 5 jerry cans that I fill and put in the tub. Gives me 250L total fuel. I stopped there because I'd read that the maximum amount of fuel we're allowed to have in our cars is 250L, but then discovered that this only relates to petrol. Because diesel isn't as dangerous, we don't have a limit. Except our GVM, of course.
I got a front runner roof rack that I had mounted by the pros 2 years ago and I only just realized that they mounted it not on the channel of my D40 but a bit further in towards the middle of the roof. About 20mm away from the channel that runs along the outside each of the roof of my D40.

I was lead to believe that the strongest point for mounting anything to the roof is the channel which is much thicker there than anywhere else. That channel is where you should be drilling holes to tap into.

Can someone please give me some insight. Am I at risk of failure if I take this roof off road and / or load it up?

What has brought this up was all the controversy lately of rhino racks being mounted on car roofs using rivets and failing. Mine has not been rivereted but screwed. ie. The rail is screwed into the roof and then the feet of the rack is installed on that. The feet hold up the rack.
Hi D40-4Life
Attached is the PDF instructions for Genuine Nissan Roof Racks witch are Rhino, in step 8 you need a very strong punch to punch down the second skin as that's how 'thick and strong the material is. This will give you an idea on where the strongest part of the roof is, they are rated at 100kg but that is recommended i have exceed this but I am prone to not following instructions.
Hope this is of some help. Peter
 

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Attached is the PDF instructions for Genuine Nissan Roof Racks witch are Rhino, in step 8 you need a very strong punch to punch down the second skin as that's how 'thick and strong the material is. This will give you an idea on where the strongest part of the roof is, they are rated at 100kg but that is recommended i have exceed this but I am prone to not following instructions.
That is a strong part of the roof, as it takes advantage of the strength of the channel without going into the channel itself. That part about having to punch down the second skin doesn't indicate anything about how "thick and strong" it is, it's only because the roof and its rigidising sections are a bit too close together in those spots for the purpose of riveting. It's actually quite thin sheet steel, about 1.2mm normally, as that tends to be the most common thickness used for automotive bodywork, at least for medium and large vehicles. It's not even a second skin, merely fairly small sections, mainly around the perimeter of the roof. As nearly all vehicle roofs are manufactured the same way if you get a chance to see any car with the roof lining removed it'll give you a good indication of what they all tend to look like. BTW, I'm not a fan of using rivets to attach a roof rack, as I've seen too many work loose.
 
75Kg might be a good, safe guide but, to the best of my knowledge, there's no such rule in any Australian state, but I'd like to hear from anyone who knows otherwise.

I don't think it is a state or country rule. The manufacturer quotes the recommended max roof load, something that will be quoted in court if you have an accident, but not something that the traffic police will pay any attention to.
 

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