Planning a partial self-made Franken-Rack

Background:

We want to mount a roof top tent (iKamper Skycamp Mini) on our 4Runner TRD Pro. As most people know, the OEM roof rack is suboptimal for such use, to phrase it politely.

Apart from a roof top tent, we wanted to place the Maxtrax boards, a shovel, maybe a Pelican case with recovery gear and, really maybe, a small water container for a quick shower on top. But, there are trade offs in all of this. So, if you're interested, read on.

Current Market Situation:

There are quite a few options out there from various manufacturers, but nearly all of them have something I personally don't like. For most of them it's the proposed "mount it with silicone" procedure. That's just a little too "caveman style" for my taste. I understand thread sealant, but just smearing the rest with silicone does not appeal to me. The BY FAR best mounted rack is the one from Gobiracks. Very well thought out, nice kit AND you can get a replacement kit for it as well. Tons of others look pretty good at first, but for most it comes back to clobbered together mounting.

There is one, that sits somewhere in the middle between Gobi and "the rest": the Rhinorack. The backbone is unfortunately only bolted to the factory mount, it does not have a front load bearing point, which means I don't want to move the tent too far forward. Plus the bars going front to back instead of side to side is just not helpful for mounting a tent. Or rather stupid to put it less politely. Why buy an 800 USD platform and then go caveman again by drilling holes in the darn thing or leaving some of the slats off? Grmbl.

Maybe it's really just me, but I'm always looking for something that is well made, well designed, doesn't cut corners and shows a lot of attention to EVERY detail. Most racks I see skimp on the mounting to the roof, but then go all out on accessories to bolt other stuff on – for additional money of course.

Bummer. I'm likely going to place an order for a Gobi rack soon (mostly based on the fact that it is a great and complete solution with well thought out mounting), but in the meantime, I still want some of the above mentioned functionality.

The Frankenrack Idea:

Now, how do I bridge the time until I maybe get a rack that has all I want? I don't want to spend a ton of money on something that is worth pennies after some use, and I don't want to buy something I don't like in the first place.

Going back to my original use case, the tent mount is the most important part of it. I can improvise all other points one way or another, but that tent has to go somewhere.

The idea is (some parts are ordered, others will have to wait for final measurements): build a tent platform for the Skycamp Mini based on the Rhino backbone system, but don't use their platform. I have the Rhino backbone system on order (the mount rails only), once these are on the truck, I'll take final measurements to build a rack on top from 80/20 t-slot aluminum pieces. 80/20 because they cut pieces to size and have a TON of information, specs, variations, etc.

There are two basic ideas I'm thinking about:

1) Pure cross bars. Just take Series 40 t-slot profiles and mount them as cross bars on top of the Rhino backbone. Simple, cheap, fast.

2) If the tent needs a spacing that I can't accommodate out of the box with the Rhino backbone bolt pattern for the crossbars, the solution is to mount a single Series 40 piece in line with the backbone, and add crossbars in-between, just as needed for the tent. I can pick heavier material for the side rails and lighter material for the crossbars. Depends on the number of bars and needed weight/deflection.

Right now, I prefer to just go with #1 for the simplicity. I can make this slightly different to be open to future additions:

1b) Make the cross bars wide enough so that I can mount another profile parallel to the base rails, just pushed out towards the sides so that the outside edge sits roughly flush with the tent. Then I can use mounting options for the t-slots to add holders for shovel or other bits, plus extend the rack forward and back a little to mount recovery boards, shovel, etc.

This will all take place over the course of some weeks to come, but I'll try to keep this thread up-to-date with:

1. Materials list
2. Exact measurements
3. Ideas and options

If you have ideas, have done this before, or just want follow along: join the party ... ;-)

 

So, current state of this is:

• I received the Rhino rack backbone system, some small blemishes due to shipping, which I'll patch up before mounting. Unfortunately, the spacing between the mounting holes (three per side) for rack on top is just a bit too long for direct use of three crossbars with the Skycamp Mini. I wanted to go with a simple and easy start, just adding three crossbars and mounting the tent to it for now. Not going to happen with this tent. So, on to the next part.
  
• What I've planned out now is just two t-slot aluminium (80/20) rails along the Rhino base, and between these two rails, I'll mount two crossbars from a slightly lighter material. The "side rails" are the standard 80/20 Series 40 (40mm cross section metric rail), since I want this one to have strong support for "pull forces" on the rails. The crossbars will be mounted with external 90 degree mounts and therefore be stabilized well, therefore I chose the "light" version of the same rail. This will give me to rails of 170cm length along the sides, and two crossbars to mount the tent on. Should be a super stable base.
  
• To mount this on the Rhino base, I've ordered 3 hole rail nuts from McMaster for the 40mm rails, together with M8 bolts (the hole setup uses M8 bolts). I chose the McMaster hardware for this since I get a longer piece to slot into the rail, so I have a longer "contact patch" inside the rail, which should prevent stress fractures at the mounting points.
• The cross bars I ordered longer than I need them, I will cut them to size when the side rails are mounted, but I wanted to keep it to a single order and I can measure this precisely only when the base and the side rails are mounted. So some rail cutting will be done. No big deal.
• The tent will then be mounted with the v1 mount system from iKamper. I would have loved to use the v2 clamps, since they are, in my opinion, a much better system, but they only support cross bars of up to 30mm height. Mine are 40mm x 40mm, therefore I'll have to go with the v1 clamping.

The downside of this is that the system is not easily extendable with reusing pieces. But since I wanted to keep the cost lower, I opted for this. If we generally like the whole rooftop tent camping situation, we'll likely order a Gobirack and sell the pieces we are installing now whenever that Gobi shows up. Another downside is that there is likely no good place to mount the Maxtrax boards for now, but they do fit nicely in the trunk above the wheel wells and since I have a bag for them, I'm not too worried about dirt. We'll see whether that changes.

 

Thanks for the info. I’ll look into this!