LONG Product Review/Comparison: Prorack Whispbar (roof rack cross bars + feet)

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DISCLAIMER: I do not work for or have any financial interest in Hubco or their Prorack products. I hope I am not in violation of any Terms of Use here, I just like testing new stuff and wanted to share my results and experiences with this product for the benefit of other Audi enthusiasts. Perhaps Hubco (or one of its retailers) will consider becoming a supporting vendor one day.


Needing some cross bars for my Avant's roof, I started researching available products. The usual suspects included factory bars (manufactured by Thule) and aftermarket bars produced by Thule and Yakima. During the course of my market survey, I came across an interesting product called the "Whispbar" on the websites of a few UK retailers (which tend to have better selection than U.S. vendors). Manufactured by a company called Hubco under the brand name "Prorack," the Whispbar was advertised to have the quietest bar design on the market. That's a pretty bold statement, but my curiosity was piqued so I continued my investigation. According to Prorack's claims:

Prorack S-wing bars are the new generation of roof bars, taking roof bar science a long way forward. They have an aerofoil-shaped aluminium wing that generates minimal drag and therefore makes next to no noise and has a negligible effect on fuel consumption. This has been shown in test conditions to create almost 70% less drag than its major competitors. It is truly a product for our times and it’s no surprise to see it winning prestigious design and environmental awards.

As the winner of the iF (International Forum) Product Design Award in 2009, the Whispbar started to gain some more credibility with me. And as a graduate of the "North Avenue Trade School," the engineering merit of this device really appealed to me too. I admit that their marketing video was especially convincing (though I admit it only demonstrates their product's performance in laboratory conditions that don't exactly replicate the real world environment).

Click here to view their shorter demonstration video.

Click here to view their longer demonstration video.



And who is Hubco? I had never heard of them before (I don't get out much), but the company was founded in 1975 by an aircraft engineer and over the past 30 years, they have supplied OEM roof rack products for Mitsubishi, Ford, Toyota, Honda, Holden, Cadillac, and Saab.

So, per the recommendation of George P. Burdell, I decided to try a pair of these puppies out for myself. Part of me had to know if the bar design would live up to the company's claims. But the other part of me knows I always like to have something different than everybody else (it's a disease, I know), and I thought it would be cool to be one of the first on our side of the pond to get their hands on some of these bad boys. I encountered one small problem: there are currently no Whispbar retailers in the United States, none of the UK retailers would ship to the U.S., and Hubco is based out of New Zealand. Turns out that wasn't a problem at all. Hubco already has plans to expand into the North American retail market, and were happy to ship me some bars at the same retail price one would expect to pay once they do arrive on our shores. But now I had to decide which product configuration I wanted to order. Prorack offers 3 styles of bars (that use the same modular components):





The bars can be combined with an assortment of detachable feet, depending on the application. This is not a novel concept, but does enhance the value of your investment should you want to transfer your bars to another vehicle.



I opted to go with the flush "OEM-style" bar for aesthetic reasons even though they give up a few inches of mounting area to the longer "through" bars. The "rail" bars don't fit the B8 factory rails, so those were not an option. The parts I ordered included the following:

- S5 flush OEM-style bars
- K421 foot adapter kit
- Generic roof box adapter kit with dipped u-bolts shaped to the profile of the bar (not needed for my particular roof accessories, but thrown in just in case)
- Foam inserts (more on this later)

Prorack shipped my package via FedEx with tracking, and they were on my doorstep 3 days later (gotta love the speed of international freight these days).





Here are the contents of the single package, which was sufficiently protected with bubble wrap.











The K421 foot adapter kit, roof box adapter kit, and other accessories were carefully packaged inside the S5 roof bar box.





Here are the bars installed on my 2009 A4 Avant, in the factory specified locations (as indexed by the female keyholes in the back of each factory roof rail)



















A reasonable amount of sunroof clearance, depending on the clamping mechanism used by your roof rack cargo accessories.

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So what do I think of the Hubco Prorack Whispbars, now that I have seen them in the flesh, mounted them on my car, and lived with them for a while? Here are my findings, including notes from my comparison with the genuine Audi accessory roof bars (which I also tested).


Design/Appearance: 9 out of 10

In general, most roof bars look kind of dorky, but I think these bars are hawt (and I've already received a few compliments on them!). The bars themselves were thicker and wider than expected. I don't know why I assumed they would have a smaller cross-section, but their size and girth surprised me when I opened the package. I initially worried that the bars would look too chunky on my car, but they immediately grew on me and I think I prefer the masculine beefy look to some of the thinner, fragile-looking bar designs that I have seen on other cars (not B8's). If I'm being picky though, a 4:5 scale version of these bars would probably be "perfect" to my eyes.

The bars have the standard anodized aluminum finish with a satin texture. Nothing special there, though I do notice a small raised lip on the leading edge of the bar--I assume it's to disrupt the airflow as it flows over the wing. There is a T-track for compatible attachments, filled with a soft rubber seal (extruded gasket). I really like the subtle "Whispbar Technology" logos printed on the ends of each bar.

I'm not crazy about the bright white and blue "Prorack" logos printed on each foot though. I guess they have to advertise someplace, but they are a little too in-your-face (3-dimensional embossed lettering or a low-key silver monogram would have been nicer IMO). The handsome feet are finished in standard matte black plastic, with nice beveled edges, rounded shoulders, and a contoured profile that suits the Whispbar wing design well. The lock tumbler is readily accessible, but are always exposed to the elements too. I discovered that the flush bars and "through bars" most likely share the same clever foot base design, with a smooth plastic cover (unique to each bar type) covering access to the adjustment knob. So if I ever did want to switch to the through bars, I could probably re-use the same feet bases and just buy the longer bars and different foot covers.

Compared with the Audi roof bars, the Prorack Whispbars look marginally cleaner to me (from certain angles) because the flush bars terminate at the feet. The Audi bars are like Prorack's "through bars" and extend beyond the feet by a few inches, increasing payload area accordingly. The Whispbars have a slight arch to them that naturally follows the contour of the A4's roof. I like this custom-fit look a lot, as it is prettier than the perfectly flat (and starkly functional) Audi cross bars, but time will tell if this aesthetic trait will prove less practical. The peak of the arch never interfered with my Yakima roofbox, so I don't think it will cause many problems with other accessories either. It's ironic that the one-size-fits-many Prorack looks like it was custom tailored for the B8 and belongs on the Audi (because of the arched bar and other design features), because the genuine Audi bars look more generic to me.

Photos of genuine Audi bars showing flat platform (no arch in crossbars):





The intersection of foot and bar on the Audi product is more elegant, with the simple extruded bar appearing to rest atop graceful arches with soft edges and corners. The Whispbar feet look a little more angular (sharper corners and radii) and contrived to me, and the extra part lines and busy underside recess detract from the overall harmony of the composition. The Audi feet (falsely) look like they were shaped by heating and bending soft gooey molten materials, while the Prorack feet appear hewn or carved from a solid block. I can't seriously fault either design though, as they are both generally appealing to me. But I think the Prorack has the slight edge (visually) for me. Others may of course disagree.




The feet on the Prorack Whispbars are a little shorter and have a smoother satin finish, while the plastic feet on the Audi bars have a rougher "pebble" finish that seem more rugged and scratch resistant than the Whispbars' feet. I prefer the simple flip-up covers on the Audi feet, because you don't need to fumble with a key to access the adjustment knob (which features Thule's standard security keyed bolt head). This method of attaching and removing the bars from the car is much faster than having to insert a key, remove a cover, then access the adjustment knob on the Whispbars. The locked covers on the Prorack may discourage casual tampering though. Snow-dwellers may prefer the large-handled wrench for tightening and loosening the clamps on the Audi feet, as the twist knob on the Prorack feet may be harder to use with large gloves on.


Construction/Craftsmanship: 8 out of 10

I notice minor deficiencies like excess flashing, exposed part lines, and inconsistent seams and gaps where the plastic cover mates to the foot pedestal. Overall, I'm quite satisfied with the quality of materials and craftsmanship. All of the fastening hardware are top shelf, and Prorack includes any necessary hand tools to assemble and adjust everything. The (stainless?) metal clamping plates (with the male studs that lock into the female holes on the inside edge of the roof rails) were fabricated with precision and include a soft gasket material on the mating surface to protect the easily scratched factory roof rails. The telescoping adjustment mechanism to increase or reduce the length of the bars (basically relocating their anchor points within the feet by spreading the latches further apart) feel solid and have positive engagement. The bars are lightweight but very rigid. They are rated for a 75 kg load and I don't doubt their ability to support that much weight (I tested a full load of ~150 lbs during the holidays). The feet have a nice weight to them that promote the sense of ruggedness. The rubber seals at the bottom of the feet mate nicely with the factory roof rails, and have some kind of waxy (silicone?) preservative coating or sealant on them to protect them.

Compared with the Audi roof bars, I would say the Prorack's molded parts don't fit together quite as nicely as Audi's feet and bar assemblies (which, to be fair, come as a solid piece with feet already permanently attached, with fewer moving parts or configuration combinations). The Prorack Whispbars are noticeably lighter but feel about as sturdy. However the Audi bars are rated for slightly higher payloads (90 kg or almost 200 lbs. vs. "only" 75 kg or 165 lbs. for the Prorack Whispbars). The plastic covers on the Prorack feet are flimsier than the Audi feet covers (or "flaps"), but the Audi flaps don't like to stay open very long before sagging closed again. I wonder how much periodic maintenance the lock tumblers on the Prorack foot covers will need, and if they will be at risk for failing in harsh conditions. They could also ice over and be more difficult to use, vs. Audi's simple flap cover that requires no key to open. While I'd definitely say the Prorack bars are constructed to similar standards of precision and quality as the Audi (Thule) bars, the Whispbars seem a little more fragile because they have more adjustment mechanisms (and thus more opportunities for failure). There's a lot more going on with the Prorack bars, but the Audi bars are much simpler--what you see is what you get, with very few components to possibly break. It's too soon to tell how the long-term reliability of the Whispbars will stack up, but I'm hopeful based on what I see so far.


Documentation: 7 out of 10

OK, I'll admit it took me 30 minutes to put everything together. The instructions were in English (whew), and had illustrative color photographs for each step, but some of the steps were confusing. Part of the confusion stems from the fact that the Prorack Whispbars ship with some factory-installed default feet that first have to be removed before you can install the adapter kit for Audi's factory rails. So you have to look at 2 pieces of instructions (one that came with the bars, and one that came with the feet). You're expected to follow steps 1-3 on one piece of paper, switch to the other set of instructions and follow steps 1-10, then come back and follow the rest of the steps listed below on the first paper. In hindsight, it's not as bad as it sounds, but I was eager to get the bars on the car and had little patience to RTFM. The actual actions needed to perform each step were not confusing, just figuring out where to stop one set of instructions and begin the other one. Once I had finished assembling the bars and feet, I re-read the instructions and it actually made more sense. So I chalk part of this up to my own impatience and stupidity. Still, it would have been nice to have to only refer to a single set of instructions without jumping back and forth, and another format might have made things smoother (i.e. an electronic, self-paced guide with prompts for your specific vehicle, or a flow-chart with decision trees that say "do you have this model car with these parts? If so jump to Step 5."). And I wish there was some mention about the foam inserts (more on that later under the "Performance" section).

The Audi roof bars came with less documentation, but those are pretty idiotproof and there's even a nice label with a diagram on the underside of the bars (good job Audi!). The Prorack Whispbars understandably come with more paperwork since the modular feet accept different mounting components for different vehicles, and the telescoping cross bars need a little bit of explanation the first time you use them.


Fitment/Usability: 9 out of 10.

The bars and feet mate to the car perfectly, and the telescoping bars made it a simple affair to customize the length of the bars for front and rear fitment. It's somewhat tricky locating the female stud recesses blindly on the inside edge of the factory rails while trying to mount the bars for the first time (you don't want to scratch the bars or your paint!), but once you've indexed your position correctly, tightening everything down was as straightforward as turning a knurled knob. And I'm sure it goes much faster with practice.



I'm hesitant to give the bars a full 10 out of 10 though, because I'm skeptical that every cargo accessory will be able to clamp to the wide bar design. Prorack says their bars are compatible with all of the common OEM and aftermarket attachment mechanisms, but their unique bar design can't possibly have 100% universal compatibility. That being said, the Whispbars accepted my Yakima SkyBox Pro roofbox just fine.















Compared with the Audi roof bars, the Prorack Whispbars only engage the roof rails from the inboard edge and otherwise "rest" on top of the factory rails. The Audi bars have an outboard clamp that grabs the recessed edge of the factory roof rail, and makes for a more positive engagement when combined with the male studs on the inboard side of the rails.

Audi's bar feet are pictured on the left (Prorack Whispbars on the right):





I do like that the Audi bars create a perfectly flat platform for your cargo (from front to rear), because even though the roof slopes from front to rear with a crest in the middle, Audi designed the feet to stand perfectly vertical at the factory mounting points. The Prorack Whispbars, on the other hand, mount perpendicular to the car body because the feet are designed to work on many vehicles and are interchangeable front to rear. While the Prorack feet are canted slightly outwards (when viewed from the side of the car), it hasn't interfered with or affected accessory fitment. Most accessory clamping mechanisms take this into account anyway, and can achieve a positive grip even if the bars are sloped slightly upward or downward.

Audi bars (more upright feet position):



Prorack Whispbars (more radial feet position):




Performance: 10 out of 10

So do the Whispbars live up to their ambitious claims? Well, the answer is yes if you assemble them correctly! When I first installed the bars on the car, I didn't use the foam inserts that were provided by Prorack (I didn't know they were needed). It turns out these foam inserts play a critical functional role in the performance of the Whispbars. And when I drove over 50 MPH without the foam inserts, I could hear a distinct whistling sound above my head that increased in volume and intensity as I drove faster. This was a real head-scratcher (and disappointment) for me, so I examined the bars to make sure I had assembled and installed them correctly. I determined that the exposed channel slots on the underside of the bars (pictured below) were a possible source of the whistling noise. Those slots were only exposed on the front bars because the front bars telescoped to a longer position to fit the wider width of the car at the front foot position (on the shorter rear bars, the holes were not visible and covered by the foot housing). Why do the holes make noise? The same reason your breath makes sweet music as you blow air across the top of a flute's mouthpiece (or beer bottle opening).





I tested and confirmed my theory by placing some Scotch tape over the holes and going for a test-drive. To my astonishment (and pleasure), the bars were "whisper quiet" at any speed. I asked Prorack about this, and they told me to make sure the foam inserts were installed to plug the channel slots on the bottom of the front bars. "You mean the foam plugs inside the plastic baggie?" Doh! LESSON: USE THE FOAM INSERTS. I hope Prorack will revise their kit instructions or perhaps install the foam inserts at the factory (depending on fitment, as the channel slots won't be exposed for every application).

After the tape was removed and the foam plugs were installed, I was ready to rock-and-roll and do some proper testing. [Please remember, this limited testing is with bare bars only (no fairing, no cargo accessories mounted). And it wasn't exectly instrumented (I don't have a dB meter). But I did do back-to-back comparisons with the Audi factory bars and the Prorack Whispbars.] In the name of science, I found myself a deserted rural road and got to work...

I expected the Prorack Whispbars to be relatively quiet (certainly making less noise than other bar designs), but what I heard (or didn't hear, rather) exceeded my expectations. The Whispbars are virtually silent! Where other bars (factory Audi bars included) start to whistle, hum, or "whoosh" over 50 MPH, these bars are completely silent at all speeds tested (I won't say specifically what MPH I reached, but it's faster than any reasonable person would likely travel with or without a roofbox). At around 85 MPH, the general wind noise in the cabin increases dramatically, but it's about the same as when driving without the bars installed. When I tilt and lean my head to identify the source of most of the wind noise, almost all of it seems to be coming from the side mirrors (which were redesigned on 2010 B8 models, so this may be improved on other cars), and not from the bars themselves. The same cannot be said about the Audi bars, which promptly remind you of their presence at typical highway speeds with a soft whoosh and humming sound (easily overcome by turning up the stereo volume though).

I am curious to know how these bars compare to other products made by Thule and Yakima (and if they compare favorably to products used in combination with a fairing). At what speed do those bars begin to whistle (when mounted bare with no cargo gear)? Without those other points of reference, it's hard for me to say conclusively that the Whispbars are the absolute quietest bars on the market. Also, not many people drive around with bare bars, and often have bicycle or kayak carriers installed, contributing to overall aerodynamic drag, noise, etc. One thing is for sure, the Whispbars won't factor greatly into any of those equations because they are almost silent. For those of you who like to drive around with your bars installed full-time (like many minivans and SUVs do), rest assured that these bars will never call attention to themselves (until you look out the sunroof, or gaze back at your car in the parking lot).

I also expected a hit to fuel economy, but I'm happy to report that my mileage hasn't suffered at all over the past few tanks of gas. So even though the bars certainly affect the airflow across the roof of the car, they're still slippery enough to prevent making a noticeable dent in MPG. Somebody in New Zealand did their homework. (For anyone wondering, I did lose 3 MPG with the Yakima roofbox attached, but that's not Prorack's fault and cannot be totally attributed to aerodynamics since I had 3 other adult passengers, a 60 lbs dog in the rear, and 150 lbs. of cargo on the roof too.)


Value: 7 out of 10

With a retail list price of around $370 a pop, the kit including the bars and feet is not cheap. But that price point does compare favorably with other competitor products, considering its high quality construction and low-noise performance. I imagine prices may also come down a little once Prorack products become more common in the marketplace, helped by sales promotions, rebates, and discounts, etc. But even at full price, I am very satisfied with the Whispbar product. And it's good to know I can re-use some of the pieces should I switch vehicles later. I do wonder, however, if the unique cross-section of the bars might require purchasing additional adapters and other fitting kits to accommodate other accessories that would normally mate right up to more conventional bars.

Compared with the Audi roof bars, the Prorack Whispbars have a lower list price but everyone knows that the Audi accessories often have 10-20% off sale coupons. So I'd call it a wash.


Conclusion:

Without hesitation, I can recommend the Prorack Whispbars for anyone looking for a solid platform for their gear that looks great and generates nearly imperceptible wind noise. They also have a very responsive customer service department with courteous and knowledgeable staff.

I tried to be fair and objective while evaluating this product, and I hope others find this review beneficial. Please let me know if I can help answer any questions. I'm happy to take measurements or more photos if needed too. I hope you enjoyed reading this review as much I enjoyed writing it.