Roof Rack Functional Failure: AGAIN!

Looking pretty again!

I had been collecting parts to make what I think will be a final change to my micro-tower setup. Yeah, right: Will it ever be “final?” 😀 I had delayed the change until after performing my car’s annual paint maintenance. For that, I took my car to a detailer who supports a lifetime warranty on a ceramic coating that he applied in 2022. I remove the roof rack and antennas each year to give him full access to the rooftop and door jambs. Removing the roof rack relieves all tension between the rack’s towers and its crossbars; so, it’s a great time to check the sturdiness of each component. I discovered my first functional failure in 2023 and shared a comprehensive write-up. I replaced the rack’s towers and reconfigured my antenna setup to be less stressful to the rack. My inspection in 2024 indicated that my changes were a success! Unfortunately, 2025’s inspection revealed that the same component is prone to functional failure, even if it took a little longer with the new antenna configuration. My “final change” to the micro-tower will be even lighter and less stressful to the rack, but I still think it’s time for a different roof rack altogether.

I’d like to clarify that this was not a structural failure. Nothing cracked, broke, or fell from the rack. In fact, most drivers wouldn’t have even noticed this issue. Instead, this was a “functional failure.” What does that mean? When a product is in its design phase, a list of requirements or “functions” is created so that engineers know what kind of design they should consider. I don’t know what roof rack designers list for functions; so, I’ll provide some notional examples. Some of the functions that a roof rack might need to perform could include:

• Carry 165 lbs without detaching from vehicle.
• Carry 165 lbs without damaging vehicle.
• Carry 165 lbs without deformation of rack components.

Side thought: This level of design and planning is why I do NOT consider it wise to buy cheap knock-off roof racks from bargain websites! The inexpensive products may LOOK like the originals, but costs were saved SOMEWHERE, be it metallurgy, thinner crossbars, cheap fasteners, etc.

My rack was able to carry the tower without a failure in the first two functions; however, a failure occurred in the third notional requirement, “…without deformation of rack components.” Referring to the image above, I detected the problem at “P” instead of it progressing to “F.” As stated in the original failure analysis, I recognize that I’m applying forces to the rack that it wasn’t intended to endure. Still, I think I can find a better rack that can coincidentally handle the job. This image shows the connection points for each corner of the roof rack (damaged tower on the left, new tower on the right). The crossbars and their load are fastened by a single M4 screw at each corner, the component that I’ve always known to watch over time. Sure, the weight is supported by the rack, but UPWARD forces are also applied as the vehicle moves on the road, especially if I strike any tree limbs (which did not happen during the past two years). Any upward force is spread across the tiny cross section of the M4 screw head and its curved mounting face. Sure, the screws survived just fine; however, their mounting faces did not.

This photo shows how the mounting face had mushroomed upward, which limited the clamping force between the rack’s towers and crossbars. This is the functional failure on this rack. I like my Yakima Jetstream crossbars and the MightyMounts that I use for fastening Superstrut. Unfortunately, every Yakima rack tower that’s compatible with my “naked roof” uses the same M4 screw head mating surface as the ones that failed in my current setup. Therefore, I’m moving to another brand and configuration that may provide more strength. AGAIN, this is not a design flaw with the Yakima rack; I’m using mine beyond the scope of its intended purpose. Still, replacing these towers again would be like eating at a buffet with terrible food just because their plates are huge! 😉 I think I can find a stronger design.

This photo shows Thule’s “flushbar” design. In this case, the crossbar slips over a large mating surface and is locked into place by a locking pin, an adjustment screw, and the fact that the rack tower is clamped into the door jamb. The main fasteners and their mating faces look larger, too; so, there’s less chance of mushrooming. I’m not saying that these surfaces cannot fail, but there appears to be more checks in play to keep everything where it belongs. I’ll know more when I have the rack in-hand, but I won’t know if the rack is stronger until I’ve used it for two years or longer. Regardless, there are a lot of features in this rack that simply make it better than the Yakima rack that it’s replacing.

Why am I not showing photos of this new setup on my car in this write-up? To be blunt, this solution is more expensive than I can afford right now, especially in the wake of a major foundation project on my home. While I save for this purchase, I also need to make some design changes to my antenna setup. Flushbar racks do not have any overhang with the crossbars. My current design, shown in this photo, uses the overhangs for the vertical antenna mounts. Having lost these areas and about 12 inches of crossbar space, I need to imagine new ways to mount my vertical antennas and route the feed lines from the shorter crossbars into the car. I have ideas, but will share them with the new reveal, which I hope to do this fall before we see freezing temperatures. I’ll miss ARRL’s September VHF contest, but hope to be ready for January’s VHF contest. See the photo album below for a sneak peak at what I’m planning.