Silca claims its new aero socks could save you 8 watts

Ankle socks, tall socks, overshoes, aero socks, UCI bans, and Kinesio tape. Only cycling could care so much about socks. 

For most, the sock is all about comfort or style, but modern so-called “aero socks” provide an aero advantage for the performance-minded. Never one to miss a marginal gains opportunity, Josh Poertner, CEO at Silca, has unveiled the brand’s new aero socks, the latest in what’s becoming a long line of watt saving goodies. 

Aero socks are now commonplace in the pro peloton and time trial scene. Although the UCI has set an upper limit for the length of socks, the aerodynamic gains are still real. This aero gain results from the ribbed lycra, or trip strips, on the sock cuffs. These ribs, or turbulators, trick the airflow into adhering to the leg, detaching later and in so reducing the pressure wake behind the leg. Long story short, aero socks make you faster. The gains can be surprisingly large.

In a video on the Silca Velo YouTube channel, Poertner explains the mind-boggling impressive savings a good aero sock offers and some of the difficulties with the current, mostly lycra, offerings. From socks slipping down in the rain (I can attest to that, see Everesting part two) to blisters and perhaps worst of all, riders passing up on a suggested 12w saving at 50kph for “critical days” only, seemingly Poertner had enough. Silca set about making a knit fabric, reliable and everyday alternative to the lycra aero sock. 

Working with a sock and hosiery manufacturer in Italy, Silca focused on balancing “the aerodynamic requirements of the sock… with making a damn good sock.” The result is what Poertner named the “Silca Aero Sock Technology”, offering a claimed 4-8 watt saving over “standard socks.”

The sock features a smooth surface down the front of the leg, with three rows of turbulators disguised as a simple sock design on the sides. The turbulators are simply slightly raised profiles designed to turn laminar airflow turbulent, similar to that ribbed fabric on other aero socks. The turbulators introduce small vortices in the boundary layer which energize the flow and promote flow attachment further around the leg.

What does all this mean? Well, according to Silca, keeping the airflow attached for longer reduces the pressure wake behind the leg and results in a 4-8 watt drag reduction when compared to standard socks. Silca has not specified the speed this saving is observed at but, interestingly given the reliability and comfort focus for the new Aero Socks, Silca says the saving is equal to that of a ribbed lycra aero sock. 

This is the first time we have seen a knit fabric used in aero socks, an area dominated by lycra options, so we will have to wait for more testing details to see how exactly this saving is achieved. We will update this article with more information as we get it, including a long term review.

As we have become accustomed to with Silca, the attention to detail in the sock design goes well beyond many offerings. The socks are knit from “Q-Skin, a silver-ion infused polyamide” which is said to be anti-bacterial, softer, and offer better moisture control than other socks. Silca even went as far as to opt for what it claims is “the most minimal toe seem possible in a sock” by closing the toe area in the production machine rather than after as per most sock manufacturing. 

The Aero Socks are available in four colourways, “pro-white”, “classic pink”, “bright lights”, and “Belgian”, priced at $30. 

Silca.cc