Aero Socks: The Most Affordable Marginal Gain?

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My cycling friends and I geek out on all things aerodynamics. So, it was inevitable before we went down the rabbit hole of aero socks.

While skeptical initially, I was quickly sold on the benefits of aero socks. They’re arguably the most cost-effective, lowest-hanging fruit for marginal gains.

Nowadays, I use them for ultra-distance gravel races. But it’s at the high speeds of triathlon, time trial, and road cycling where aero socks shine. At higher speeds, the role of aerodynamics comes more into play. So small things like socks can have a considerable difference.

I’ve tried a few different products, and there are a couple I like more than others. But first, let’s digest the scientific advantages of aero socks.

What are Aero Socks, in Simple Terms?

Aero socks are a type of cycling sock that’s engineered to minimize air resistance and improve aerodynamics around the lower legs and ankles. They are made with unique fabrics that effectively distribute airflow more efficiently than normal cycling socks or no socks at all. 

The fabric is designed to add texture and greater surface area to the leg, which keeps air closer to the body and reduces the airflow’s wake, effectively minimizing drag. 

While the exact performance gains vary depending on the cyclist’s speed, riding position, and other racing gear, aero socks can provide a cost-effective way to shave costly watts and improve performance.

How Many Watts Do Aero Socks Save?

There’s a lot of data on a lot of different socks. Brands conduct their own wind tunnel tests, measuring watt savings at certain speeds as well as a metric known as CdA, or the coefficient of aerodynamic drag. Here are some examples:

• A test of Rule 28’s aero socks found 13.6-watt savings at 31mph/50kph (Source)
• Silca claims that their new aero socks can save between 4 and 8 watts over standard cycling socks (Source)
• Based on a solid write-up at The Pro’s Closet, aero socks can save up to 8 watts (Source)
• Rule 28 claims that their aero socks could save over 12 watts versus a standard pair of cycling socks (Source)
• Socks4Watts claims that their cycling aero socks save 3.3 watts at 20mph, and 5 watts at 30mph (Source)

If you’re a real aero geek, I suggest watching this insightful discussion about aerodynamics, the “most effective marginal gain“ between SILCA’s CEO Josh Poertner and pro cyclist Dylan Johnson. 

In the video, Poertner says “At 30mph, the best aero socks can be worth 12 to 15 watts, depending on the rider.” That, of course, is at the very elite end of the spectrum. But other studies show similar numbers. 

Testing on Nopinz aero socks versus standard socks proves a 5-watt advantage at 26mph/42kph. But when speeds exceed 30mph and up, the potential watt savings multiply (up to 15 watts) as speed increases.

Rule28, one of the most reputable brands of aerodynamic cycling apparel, tested its aero socks against five other comparable socks on the market.

Not only did Rule28’s aero socks top the podium with the lowest CdA, but at speeds of 28mph (45kph), they saved between 2-11 watts compared to competitor aero socks.

Watts savings and aero gains depend on many factors. Sock length and rider speed are the two most influential variables, often pushing the watt savings into the double digits.

But for most cyclists who are investing in traditional mid-calf aero socks and don’t average over 25mph/40kph, you can expect to save around 3-5 watts on average.

What are the Best Aero Socks?

Having experimented in the world of aero socks, I’ve tried a few different products that I briefly review below. 

Rule28 Aero Socks

A true innovator in aerodynamic apparel, Rule28 has a reputation for its aero socks. You can tell by the material alone that the socks are high-tech and mindfully engineered for top performance.

Rule28’s aero socks are touted as the “fastest socks on the planet.” They use a striped rib design to generate turbulent airflow and reduce drag. Based on the tests mentioned above, they can save upwards of 10 to 15 watts at very high speeds.

Despite having oversized grippers, the common issue with Rule28’s aero socks is that they slide down on the leg while cycling. This was a frequent issue for me, especially given the large size of my calves. I’ve learned that applying Tuffner Pre Tape Spray on your legs beforehand can prevent this, so I plan to give that a try next time I wear them out riding. 

When they do stay up, I can honestly say I feel a difference with these socks, especially going fast in the aero position. They’re priced at the high end of the spectrum. But still an attractive option just under $40. 

Rumor has it Rule28 is unveiling a new and improved aero sock soon. See their complete line-up at Rule28.com.

Specialized Hydrogen Aero Tall Road Socks

The Hydrogen Aero Tall Road Socks from the well-known cycling brand Specialized are a popular, low-cost option for cyclists. While they retail at $30, I’ve seen them consistently on sale for just $17, making them an attractive bargain buy.

The socks feature a rib knit cuff that has a stripe pattern similar to Rule28’s design, which provides the sock’s aerodynamic advantage. They’re made using the company’s VaporRize Hydrogen yarns, providing a cool, lightweight, and comfortable feel.

The socks are 7 inches/17.8cm tall (in medium), so they fit right around the bulk of my calf. The sock doesn’t fit as snugly or securely as the others, so they are prone to slipping down my leg. This is largely due to the bulk of my calf muscles, but I also wasn’t fond of how the material felt.

You can find the Specialized Hydrogen Aero Tall Road Socks direct from Specialized.com or look for discounts at Competitive Cyclist.

Silca Aero Socks

While the material might not look and feel as high-tech as the options above, the aero socks from Silca are the most comfortable option, making them my top pick. 

The socks are constructed from an antimicrobial Q-skin stitching that feels like a breathable, second skin. The cuff reaches 6.5 inches/16.5cm, so they stay up on the leg without sliding down. 

Silca’s aero socks are designed with a smooth frontal surface and 3 rows of turbulators along the sides, starting just ahead of the flow separation zone. These small vortices promote flow attachment around the leg, creating less wake and drag.

Simple yet effective, I highly recommend giving the Silca aero socks a try. They’re well priced right around $30 and can be purchased directly at Silca.cc.

Last Word

All things considered, yes, I strongly believe that aero socks are the most affordable marginal gain in cycling. Sure, you might only be shaving a few watts, but given the low cost and high ROI (especially over long distances and at high speeds), you can’t find a better investment for the price.