New (to me) car likely in my future, as out 25 year old Audi tells us it is done. Will go fora new roof rack system for the new car. If we get the car we are thinking, it will have those recessed rails which both Yakima and Thule make decent rack systems for. Likely use a stacker type mount for kayaks on the cross bars.
Is there a big difference between aero and non-aero cross bars? Are aero bars less loud and/or is there any noticeable benefit to fuel economy?
At least for Thule, looks like aero bars are more expensive, but if I get square bars, Iâd need to get adapters for most things you put on the bars. Havenât looked as deep at Yakima, but I suspect I would find similar.
I canât imagine aero bars are worth paying more for. Car makers have gone to great lengths to reduce air resistance, with many of the methods being quite major and yet individually, each modification has minuscule benefit, so I doubt that slight changes in shape of something that already has such a small frontal area as a cross bar could matter enough for you to detect the difference.
If your bars make noise, you can wrap them with a spiral of rope to break up air flow. Iâve seen aero bars wrapped with rope this way so itâs obvious that in those cases, the bars must have been making noise in their bare condition. I had a Subaru ages ago that had a dealer-installed rack with aero bars and it would make a LOT of noise, but only within a very narrow range of (cool) temperatures when just the right amount of rain was falling. I have extensive miles in several different cars using round bars or bulkier bars of more crude design and have never had a problem with noise. My point here is that I donât think you can predict which bars will make noise on which cars or in which conditions, since the conditions that set a bar into resonance can be very particular.
I donât have a 100% reliable answer, but I have one car with Thule rectangular bars and another with Thule aero bars. Both have Thule tower systems that clamp onto the door frames (no roof rails). In my case, the car with rectangular bars shows about a 10% drop in gas mileage versus no rack while the car with the aero bars does not. But the shape of the carâs roofs and other factors could be at play here too.
I use home made cradles that are quick to remove, and I only attach those on kayak trips. So, my comments apply to just the bars with no attachments.
When I first got Thule aero bars for my 4Runner (with raised roof rails) 10-ish years ago, they tended to make a whistling noise that varied with driving speed and wind (speed and direction). The noise seemed to originate near the pillars. Thereâs a slot on the underside of the bars that allows the distance between pillars be changed. I covered the slot near each pillar with a 1" x 8" strip of Gorilla tape and the whistle disappeared. YMMV
I sold Thule and Yakima roof racks for may years. Iâve had both Yakima and Thule systems on my vehicles. With Thule Iâve had both âsquareâ and aero bars. What I have found is that gas mileage doesnât seem to be affected. Bar noise doesnât seem to matter much. Whatever accessory you mount on the bar of your choice will almost certainly make more noise than what you are hoping for. I tried âaeroâ accessories expecting results and just got different noise. I got rid of them all.
My advice is to choose the accesory that best suits your purpose and buy the rack system that it fits best on. Know that once you put your boat on the rack it will make a different noise. Figure out how to fix that, keep your sunroof closed and get over it. I have gone from a Thule Aero bar system with aero accessories to their âsquareâ bar with a Hullavator. With the sunroof open I hear no difference in the aero bar and the square bar. Throw any kayak accessory up there and you hear noise. My Hullavator sounds the same at my Hullaports folded down.
Not a good comparison, but the Honda brand aero bars on my CRV donât make as much wind noise as my yakima round bars did on my Outback or X-terra, the bars on both of those were wider and extended beyond the mounting towers.
The Yakima round bars have a nasty tendency for the saddles or other accessories to roll over if loading from the rear, no matter how often you tighten them down. The Thule square bars do not have this problem, nor do any of the aerodynamic bars.
Many people just like the look of the aerodynamic bars, but they are significantly more expensive than the older round or square bars. Some dealers do not carry the older square or round bars anymore and I suspect that Yakima and Thule will eventually discontinue them.
Most new saddles and accessories now fit on any crossbar.
The effect on gas mileage is minimal with different bars. Noise can vary with the crossbar, car, and speed at which the car is driven. Add a boat and everything changes again.
I agree with most that gas mileage will not change noticeably, and noise generation is not predictable a priori. I will say that aero bars are stronger than square or round bars, since they have a larger cross section. Also, the attachments tend to reside in slots in the bars, which gives a clean appearance, and they tend to look better on the car by themselves, which may matter (I prefer it cuz it makes my car look cooler).
Round will hummm at highway speed due to resonance. Its really really annoying. It can be counteracted by adding something to the bars like the Canoe Stops, which unbalance the loads and remove the resonance.
After using Aero bars, I can say they are 100x better and worth 2x the cost. You keep a rack for a decade so an extra couple hundred bucks is not that much over the life of the rack. The flatter top surface means you can load more stuff on it without dedicated mounts. The bars are more substantial. There is no risk of humming at high speeds.
If cost is an issue, look on Craigslist / FB / ND / Etc. The racks are fairly universal, you just need to buy car-specific clips and pads.
Just suck it up and pay for the Aero bars. Theyâre better in every way.
One issue that comes up in this discussion is bar strength. Do we really know that aero bars are stronger? Bigger dimensions might mean they are stronger, but it also might not. The thickness of the metal also matters. As a way of illustrating this principle (even if a bit off-topic), I am thinking of the drive shafts on older rear-drive vehicles compared to modern ones. The modern drive shafts of this type are twice the diameter or even more, compared to those on vehicles from 30 or 40 years ago, but that larger diameter simply allows the use of extremely thin metal for the wall of the tube. The modern drive shafts are strong enough for their intended function (tolerating the torque associated with propelling the vehicle), of course, but the slightest contact with an obstacle on the ground can make a dent (which will be a failure point so the shaft is ruined). By contrast, the older drive shafts also were strong enough for their intended function, but you could literally beat the rust off them with a hammer without fear of causing damage because the metal of the tube wall was so much thicker. Itâs not likely that the old-style drive shafts were over-designed. They needed extra wall thickness to be strong enough at their given diameter.
I think that engineers for roof-rack companies, if they do what engineers usually do, would design aero bars to be âstrong enoughâ by making them out of thinner metal, rather than accidentally making them stronger AND heavier than previous bars had been as a result of using the same wall thickness as was the case for bars of smaller cross-sectional dimensions. I donât know this to be true, but it would be my expectation since part of engineering is to keep materials costs and shipping weight from being higher than they need to be. Itâs just a thought.
Itâs entirely possible that smaller square or round bars are stronger than larger aero bars, because the square and round bars are made of steel which is around four times as strong as the aluminum from which aero bars are made. The aluminum aero bars generally do have some internal webs extruded in, which will help with the bending strength of the bar. Realistically, I wouldnât put enough load on my roof to worry about the strength of the bars in any case.
Crossbars and rack systems from most reputable companies will have load ratings. Vehicles with factory rails or racks will also have load ratings for things carried on the roof.
Good point. The weak link is more likely to be in the carâs specs rather than the geometry of aftermarket crossbars. For example, Ford says a 2020 Escape can carry no more than 100 lbs using crossbars with the factory roof rails, and 0 lbs directly on the roof (as with foam blocks). Also, JD Power says the manufacturerâs capacities are for smooth roads, and they should be reduced by 1/3 under off-road conditions due to the extra up/down/lateral stress.
trying the experiment nowâŚ
new Ford Maverick, averaging 43mpg so far.
Just put on Yakima so-called âaeroâ bars and will drive with them on for a while, see how mpg is affected⌠then I have some old round bars from 1992, will put those on and see.
Really I donât believe any of the âaeroâ bars are going to be significantly different from the old bars. Aerodynamics is hideously complex and depends heavily on interactions between the components. Based on what little I know about racing bicycle aerodynamics, the height above the roof of the bars will most likely make more difference than between âaeroâ or round bars. But Iâd expect all of the differences are going to be rounding errors basically - compare the frontal area of the car with that of any roof rack bars. Itâs possible there might be some weird turbulent airflow interaction between bars and roof on some cars of course.
I didnât notice any noise with round bars, on multiple different cars. The noisiest bars Iâve had were cheap âaeroâ ones on a Ford Sport Trac, those would hum and whistle along.
I had square round bars from a previous car when I bought my (more aerodynamic) current car, I looked into buying aero bars as I thought they would be an improvement over the square bars but read that the square bars are significantly stronger so I kept them. Also, side issue but do you use a wind deflector? Using one makes the bar style issue moot.
About this time last year I replaced a 2012 Hyundai Santa Fe with a new 2023 Santa Fe Hybrid. The older car had two Thule Hullavators mounted on square bars. This Spring I bought Thule aero bars and towers for the new car and mounted the older Hullavator arms on them. When not using the kayaks I do take the arms off - itâs a 10-minute max operation.
I definitely think the aero bars create less wind noise than the older square bars, and since adding the newer bars I donât really see any drop in gas mileage. There again maybe my 2023 car is more aerodynamic than my 2012 car? The aluminum aero bars are lighter, just as sturdy as the steel ones, and wonât rust. They also do look a lot nicer on the newer, more modern car.
As for load ratings, Hyundai says 150lbs max. Thule is very conservative and their engineers go on about static rather than dynamic loads. I carry two 35-40lbs fiberglass kayaks on Hullavators, with Thule straps and good bow and stern lines. Iâve done this for over 10 years at highway speeds from Canada to Florida and never had a problem.
Load ratings are extremely approximate in any case and tell you very little about the strength of the bar. Flexural strength of the bar can be measured in countless ways since the application of load can be applied at various points, multiple points, or uniformly across the span. Further, the length of the span will be different when the bars are mounted on different vehicles and span will affect the ability of the bar to carry the applied load as much as anything. And NONE of the possible configurations for evaluating the strength will match any one personâs particular load distribution, except by extreme coincidence. All you can really do is realize that the bars are significantly stronger than what any of us paddlers will ever need, and stop worrying about it. And this latest point, the idea that most car roofs are rated for less load than the cross bars we are talking about, is very believable.
Itâs hard to realize a real advantage in fuel economy if you donât mount the aero bars in the prescribed place: I have them much further apart because thatâs better for a long object like a kayak or canoe.
On both of our cars I remove the crossbars when not hauling boats. Both the different Yakima round bar systems are easy to put on and take off. Another plus is it is hard to steal a rack off the car if it isnât on the car in the first place. On my Subaru Impreza It is so easy to remove the rack that I take it off and put it in the locked car at the launch. On our Ford Edge I have the locks for the rack so leave them on at the ramp since they take more time to remove, but they arenât all that secure if someone really wanted the rack. A plus is you donât even need to buy the expensive stock cross bars as you can save money and buy 1" galvanized pipe for the cross bars. I really donât notice much in the way of noise when the racks are on, but then I rarely drive with racks on the car without boats on the rack.