Adventurous lifestyles require adventurous ways to mount things on your car, that's just straight up science. Most cars come with some basic luggage mounting options, not very adventurous. I mean, when's the last time you took "luggage" on an adventure? Never. If you did, it wasn't an adventure, it was a vacation.
There are a lot of racks out there for commonly used 4x4's, the companies that make these products do wonderful work, they just don't have much of a variety. If you don't have a Tacoma or a 4Runner, you may be shit out of luck. I've got a Rav4, Betsy, she's awesome, except when it comes to finding an aftermarket rack that fits her. No biggie, I think I can build one for less than it would cost to buy one even if there were aftermarket ones.
Question: Can I build a roof rack with the same (or more) functionality than existing roof racks made for larger 4x4 cars, for less money than a similar type of rack?
Research: It looks like the bulk of these roof racks are made from some simple and accessible components: side rails made of aluminum flat bar, cross bars made of extruded aluminum, steel or aluminum angle bar for the feet, and finally some plastic or metal sheeting for the fairing on the front.
Preparation: This doesn't require any special tools and just general shop safety, though it did require a lot of measuring and checking.
Execution: Designing this was heavily dependent on size of the factory roof rack, as well as what the roof itself would allow. There is one video out there of someone who made one similar to this, and if I'm allowed to, I'll link it below. I'm going to separate my descriptions into the parts of the overall products into their individual structures, the Main Rack, which consists of the Side Rails and Crossbars, the Feet, and the Fairing Assembly. Every piece of material here can be but to length before it ships from most online material stores, with the exception of the Fairing Assembly Side Brackets, the Fairing, and the Feet - which were all custom jobs.
Creating the main rack portion was fairly easy, all it requires is tapping the center of both ends on each piece of 3030 extrusion, and then drilling corresponding holes on the side rails where you want each crossbar to go. Make sure to use cutting oil and deburr your work. The side rails are 6061 Structural Aluminum Angle, which means the manufacturer added a small fillet on the inside of the angle, so the square edges of the 3030 are not going to sit flush, I did end up making small miter cuts on the bottom of each crossbar to accommodate for this, but you can just as easily take a file to it. I used fairly long hardware to bolt everything in, M8x35mm and they all got a torque of about 30nm, with Blue Loctite.
I only had two real variables for the placement of the bars. I knew roundabout where the feet were going to go, and I wanted two crossbars straddling each feet for good weight distribution, that's one variable, then I wanted there to be a crossbar flush with each end of the rooftop tent I was also fabricating, so that meant one at the back, flush, then one 76" in from that. Beyond that, the ones I added were just centered amongst. I thought that in retrospect I would want to add more, but so far 6 crossbars has worked fine.
The feet were a bit of a pain in the butt, admittedly. The issues were several fold:
the roof rack mounting threads where buried below the roof in the rain gutter
the rain gutters were not parallel to one another, narrower in the back and wider on the front
the rear mounting threads are perpendicular to the rain gutter, but not to the surface of the roof
I managed to squeeze by these narrow workways and figured out something to manage. The rear feet needed to be two sets of angle, rather than the one set for the front. Seen here, I needed to create a platform to hold the back of the rack. They also needed to be angled on two planes to accommodate for the roof. One angle was overcome by simply bending the top bracket to just north of 90°.
Sitting flat, you can see the second angle that needs to be overcome. I ultimately ended up oversizing one of the mounting holes to give me some rotating room.
Luckily, the front feet were easier, I only needed to overcome one angle, which just meant the feet could sit flat on the roof while being leaned forward a bit on the rack. Additionally, the width of the front rain gutters meant that the rack was sitting directly above where the feet would need to be mounted, meaning I could get away with just using one angled bar - totally planned that, yea. Totally.
I would say 80% of my frustrating in this project is owned by the fairing assembly. For this, I needed to create a cardboard cutout of the general size and shape of the side brackets, shown below in black. Then cut them out of a piece of flat bar aluminum. This wasn't particular difficult, but it took a whole. To speed things up, I cut the angle into two equally sized rectangles that were slightly larger than the shape I needed, then clamped them together, ensuring that when I cut the shape out, both brackets would end up being identical. I took one of the crossbars, which had to be a tad longer than the others, since these brackets would mount to the outside edges of the rack, and mounted it directly to the top of the fairing angle. Then I took two scrap pieces of 3030 and mounted it to the inside edge of each bracket, to serve as additional mounting support for the fairing.
I really thought I would need multiple mounting bolts for this to remain sturdy on the rack, but I ended up just using these two massive M10 bolts that I had laying around to mount this on the rack so I could loosen it to swing it up if needbe (the needbe part, I'll get to later). Surprisingly, they've held up great.
The doozy here was the fairing itself. Once I had the fairing assembly done, I mounted it on the car to get an idea of my angles. I measured out on the crossbar from the edge to the center, and marked 2" increments. Then along those lines, I laid a ruler flat against the bar and let the ruler move down until it touched the roof, and recorded that measurement. In retrospect, I should have done 1" or 1/2" increments. I transferred these measurements to the Polycarbonate, and mirrored them for the other side, making my curve. I knew I wanted the top of the fairing to extend a little bit further above the top of the rack, so I added a couple inches to do just that.
I cut out the fairing and filed down the edges before mounting the edge trim on the portion that would contact the roof. See those two little abrupt angles? That's why I should have gone in smaller increments.
Now I have every intention of mounting a lightbar on my roofrack, in fact right now it's sitting in my office staring at me... I should probably turn it off. Anyway, I like the idea of a lightbar, but I also like to minimize wind noise and coefficient drag on my car wherever I can. So when I started this project, I decided I was going to accommodate my intentions of a light in the fairing assembly design. I used Clear UV Polycarbonate, because the lightbar will sit behind the fairing, allowing light to pass through, without the cost of wind noise or reduced aerodynamics. I tested beforehand to make sure the light wasn't distorted in anyway, and there doesn't seem to be any measurable hinderance. Once completed, the lightbar will mount to the fairing assembly's crossbar and hang under it.
The rack has been on my car for most of the summer at this point, and it has been one of the best modifications I've made. I have made some slight changes to it, namely the fairing got the top corners trimmed off, and the whole assembly got moved back on the rack a bit to soften the angle relative to the windshield. In theory, anyone could follow this general guide to install one on their car, assuming their car at the very least has factory roof rack mounting points. I also ended up finally getting the low profile button head bolts that mount the fairing on.
Total cost of this project was just shy of $400 (BUTT, you could absolutely go cheaper down to $250 by substituting materials). I worked on it over the course of a few weeks, but it could easily get done in a weekend.