THE SCIENCE BEHIND AEROSOX

Independently tested and verified by Adaptive Human Performance

Testing AeroSox prototypes with Brother NRG Driverplan riders at Manchester Velodrome

Testing AeroSox prototypes with Brother NRG Driverplan riders at Manchester Velodrome


Without AeroSox...

The rough cylinder shape of a leg, creates low pressure in its wake, effectively sucking you backward.

The rough cylinder shape of a leg, creates low pressure in its wake, effectively sucking you backward.

 

WITH AEROSOX...

Turbulent air stays attached longer, creating a smaller low pressure area, resulting in less drag on the rider.

Turbulent air stays attached longer, creating a smaller low pressure area, resulting in less drag on the rider.

DEVELOPMENT

AeroSox have been developed alongside Brother NRG DriverPlan Pro Cycling over many months, utilising their attention to detail, qualitative and quantitive feedback to truly optimise AeroSox. To explain how AeroSox work, let's explain how aerodynamic drag is generated.

 

Aerodynamic Drag

Aerodynamic drag is made up of two components: pressure drag and skin friction. Pressure drag is created by the low pressure air pulling back on your leg. Skin friction is created by the action of the air flowing over your leg. The air around your lower leg typically is "laminar", this means it flows smoothly but has very little energy in the flow, so once it flows past the widest point of your leg and tries to stay attached around the back it can't resist this and separates off your leg, leaving a large amount of low pressure air behind your leg pulling you back.

 

HOW AEROSOX CHEAT THE WIND

AeroSox have been designed to energise the boundary layer air flow closest to your leg. By energising this air, it turns turbulent and is able to stay attached for longer, therefore reducing the size of the low pressure wake behind your leg and thus reducing your total aerodynamic drag. AeroSox employ materials that provide noticeable surface roughness to energise the flow. This technique is totally immune to the size of your legs and the orientation which you position the sock. This is a more stable and consistent technique to energise the boundary layer air flow over other techniques such as trip lines.

 

Summary

AeroSox employ textured material up to the UCI height limit. The textured material provides surface roughness encouraging the boundary layer to turn turbulent. This turbulent flow resists adverse pressure gradients around the leeward side of the leg, therefore reducing the low pressure zone behind the leg.

In simple terms, AeroSox change the air flow around the leg to reduce the low pressure behind the leg that sucks you backwards.

 

TEST RESULTS

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ABOUT

AeroSox were tested on the DriverPlan NRG DriverPlan Team Pursuit team. Multiple material textures and sock lengths were tested. The most successful of which then became our prototype socks that were then used to take three national titles at the British Track Championships.

All testing was conducted by Daniel Bigham, owner of Wattshop and now three time national champion on the track. Dan has an extensive background in aerodynamics first in Formula 1 as an aerodynamicist with the Mercedes AMG Pertronas team, then as a data analyst with Drag2Zero.

 

TEST PROTOCOL

AeroSox prototypes were tested against three alternatives: No socks, 6” cotton cycling socks and a trip line competitor. 

Data was collected from a crank based powermeter that was calibrated prior to each run. Ambient weather readings were collected trackside from a mobile weather station. Readings included: air density, air temperature, air pressure and humidity. System weight (rider and bike) was also measured prior to each individual run.

The protocol itself consisted of two runs - using different time durations and speeds. Run one was a 10-minute test at 45kph. Run two was a 4-minute run at 55kph. All data points were processed in a proprietary MatLab script on a second by second basis to calculate rider CdA. The results were then averaged over the test run to give a final figure. The protocol was repeated and the readings averaged for each product tested.

 

RESULTS

From the CdA value generated from these results, a curve was plotted using MatLab of the wattage required by our test rider to produce speeds using each product. These findings can be seen below as well as plotted on a graph at the top of the page.

 

CONCLUSIONS

6" cotton socks: Cotton socks increase a riders frontal area, although only slightly. This by itself would not provide any noticeable change in pressure drag in the wake of the riders leg, however the knitted construction of a cotton sock drastically increases skin friction verses actual skin.

No socks: Riding with no socks reduces frontal area and doesn't increase skin friction.

Trip line competitor: Trip lines can be a good method of inducing turbulence, however they are limited in their applications. This is due to the fact that they require precise placement. In real world applications, where riders leg shape and leg velocity is variable, not only between individuals, but also at different moments of the pedalling phase. If trip lines are not correctly positioned then excess skin friction can occur as well as minimal reduction in pressure drag.

AeroSox: AeroSox employ a textured material that provides surface roughness encouraging the boundary layer to turn turbulent. As the entire surface of AeroSox is textured, they are immune from changes in orientation or leg shape.

Our results have been replicated by Adaptive Human Performance, an Aero and Physiological Testing expert based in Victoria, Australia. He can be found on Instagram @adaptivehp

If you have any questions about AeroSox, please fill out the form on the 'Contact Us' page and we will do out best to answer you.