Roof racks are definitely a useful addition to a car. But if you’ve ever been driving fast and noticed a whistling noise, you’ve probably wondered how to stop roof rack noise. Here are some suggestions:
- Remove the roof rack
- Fit a roof rack wind fairing
- Pad the crossbars
- Fit aerodynamic crossbars
- Use edge bars instead of load bars
- Build your own wind deflector
I’ll cover these in more detail below, but first, we’ll go through some information on why roof racks make this noise. It’s always worth doing a quick bit of troubleshooting to ensure you’re not just masking a bigger problem.
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Why Do Roof Racks Make Noise?
If you’ve ever owned an SUV or similar car with a roof rack fitted then you probably know this issue all too well.
You’re driving along and notice an irritating whistling noise when you hit a certain speed. But what is it, and is it a problem?
The whistling noise from the roof rack is caused by wind passing over the bar on top of your car. If the surface (the roof rack) is a consistent shape, the airflow develops a tone, hence the whistling.
The technical name for this is Aeolian noise (also spelled Eolian). Working out the point at which the wind begins to make a noise involves a fairly complicated formula that isn’t particularly relevant.
What is important is that the noise is dependent on the speed of air over the surface, the surface’s shape, and its resulting drag coefficient.
Drag coefficient is the formula used to calculate drag and is dependent on surface shape, its inclination, and flow conditions.
While this has the potential to become very technical, it’s worth knowing some basic information about aerodynamics in order to understand how to solve the problem.
In short, to solve the problem of roof rack noise, you’ll need to disrupt the flow of air over the surface. Alternatively, you’ll need to make the roof rack more aerodynamic. This is possible in a few ways, which I’ll cover below.
If you don’t already have a roof rack on your car but are thinking of getting one, consider the information below before doing so. While I’m not trying to put you off getting a roof rack, it’ll be worth trying to avoid this problem before it even starts.
You can buy roof racks specifically designed to prevent this issue, so take a look at these. But if you already own one then you’ll want to try the following steps.
Also read: How to Temporarily Quiet Down a Loud Car Exhaust
How To Stop Roof Rack Noise
There are a couple of different options for stopping roof rack noise. Each of these is pretty effective, so you shouldn’t need to use more than one. Some require a bit more work than others, so just go with the one that’s most convenient.
1. Remove the roof rack
This might seem obvious, but the best place to start is to simply remove your roof rack when you’re not using it.
When it’s in use, whether with a top box or something else, the whistling noise generally isn’t an issue because there’s something up there disrupting the airflow. A top box, for example, will change the air current over the roof of your car.
Not all cars will have the option to remove the roof rack, particularly on larger models. But if yours does, I’d recommend this as the most effective option for solving the problem.
2. Fit a roof rack wind fairing
This is such a common problem that a market has developed for wind fairings (Amazon link), also known as wind deflectors.
Their purpose is fairly self-explanatory: they deflect wind away from the roof rack, which effectively removes the whistling noise.
Many wind fairing brands are universal and will fit most cars, but you can also get models in varying lengths. They simply clip onto the front crossbar and rest on the roof of the car.
Typically you can expect to pay up to $120 for a wind fairing, although this will vary depending on brand and size. Some brands only make wind fairings compatible with their roof racks, so check this out before buying.
The price is also impacted by material and build quality. Realistically, you’ll want something fairly durable and of good quality in order to get your money’s worth.
You can even find some wind fairings made from carbon fiber, but this isn’t that necessary.
3. Pad the crossbars
An effective way of stopping roof rack noise is to simply disrupt the airflow. This is much easier than it sounds because you just need to cover the smooth metal surface that helps to create the noise.
The easiest way to do this is with crossbar pads (Amazon). Typically designed for protecting things like surfboards, these do a surprisingly good job in this situation.
Using crossbar pads disrupts the airflow because it makes the bars more rounded, and the soft rubber material has a higher drag coefficient. Considering you only need to pay around $30 for these, it offers a quick and easy solution.
Just be aware, though, that this option might not prove as effective when driving at higher speeds.
Unlike a wind fairing, which changes the airflow, this option just changes the drag coefficient. This means that the whistling noise will most likely still happen at some point.
4. Fit aerodynamic crossbars
Much like wind fairings, companies have created aerodynamic crossbars (Amazon link) to help solve the problem of roof rack noise.
These include a number of design features to reduce drag, including:
- Integrating the bar and foot
- A lower profile to change airflow
- Wind diffusion grooves
- Oval shape for reduced drag
The wind diffusion grooves are perhaps one of the most interesting aspects of these crossbars. They create a wind vortex rather than a one-directional airflow, which effectively removes the whistling issue altogether.
What’s more, they’re specially shaped to reduce drag. Normal crossbars and roof racks are usually square or round. Aerodynamic crossbars are oval in shape, like an airplane’s wing. And, like airplanes, this makes them more aerodynamic.
Another advantage is that they’ll slightly improve your car’s fuel efficiency for the same reason. While it won’t save you thousands, every little step helps.
The only major downside is that they’re quite expensive. One of the leading brands, Thule, sells its aerodynamic crossbars for around $200-300. But it just depends on how annoying you find the whistling noise.
5. Use edge bars instead of load bars
Roof rack crossbars come in 2 types: edge bars and load bars. Load bars are the most common and are designed for transporting larger and heavier objects. This is where they get their name.
To improve load capacity, they have a larger surface area and are generally longer than edge bars.
Also, they’re usually a box bar shape, meaning they’re square. Edge bars, on the other hand, are usually round or oval in shape.
Edge bars are also shorter, reducing their surface area. While you can’t transport as heavy loads with edge bars, they’re still fine for most transporting jobs. For example, you’d be fine fitting a top box to an edge bar.
Many edge bars will also be marketed as aerodynamic crossbars for this reason. But they’re 2 different products most of the time.
If you want aerodynamic crossbars, then make sure they’re the real deal. While edge bars are more aerodynamic than load bars, they’re still not as effective as a specifically designed product.
6. Build your own wind deflector
Although some of these options aren’t particularly expensive, sometimes you might want to just try a DIY method instead. If so, try building your own wind deflectors for your crossbars.
All you need to do is disrupt the airflow over the crossbar, as explained in the wind fairing option. A good option for this, surprisingly, is a bungee cord.
The bungee cord basically changes the surface of the crossbar and breaks it up in a way that prevents Aeolian noise from occurring. This is because the cord channels the air, much like the wind diffusion grooves on an aerodynamic crossbar.
All you need to do is wrap a bungee cord tightly around the front crossbar on your car. For many models, a 4ft cord should do, but be sure it’s really tight. If not, you’ll need a shorter cord.
If the bungee cord has hooks on either end, this should be enough to secure it in place at both ends of the crossbar. If not, then tie it in place instead.
The more secure you can make it, the less chance you have of it pinging off under its own tensile strength.
Be aware that this isn’t the most effective option on the list and will probably still create noise at high speeds. If this happens, try one of the dedicated options above.
Some Final Thoughts
As you can see, there are a few options for how to stop roof rack noise. The key is understanding how it’s caused and knowing how to overcome this phenomenon.
You can get away with not spending too much money on this, but if you’ve got a larger budget then definitely try an aerodynamic crossbar. These have advantages that go beyond just reducing noise.
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