Free speed - wind tunnel lessons

Training day by day: stage 13

We all want to be faster. In order to go faster, you have four choices – increase power; reduce your weight, therefore improving your watts per kilogram; improve positioning and aerodynamics on the bike; or buy fast, and usually expensive, equipment.

Anyone already training with a well-designed training plan is investing in the power increase, which hopefully will coincide with a reduction in body mass, so what’s next? Aerodynamics!

In the past decade, top bike, wheel, component, clothing and helmet manufacturers have been investing heavily into research and development of their products, and the wind tunnel is where they optimize these products for speed, or, more technically speaking, a reduction in drag. Non-disclosure agreements abound, meaning technicians of wind tunnels across the world are privy to lots of cool secret information!

It really is free speed. Last week, Ben Day of DaybyDay Coaching observed an already fast athlete save a further 16 watts by the end of the session in the tunnel. This may not sound like a lot, but think how hard and how long you have to train, or just how much you have to spend on equipment in order to gain 16 watts at your lactate threshold.

The FASTER Performance Center, a boutique bike shop/recovery center/wind tunnel combo, located in Arizona, relies upon Aaron Ross as the director of technology and biomechanics (he’s a bike fitting and wind tunnel technician guru). Combining his knowledge with 'shred' after shred of wind tunnel runs has given Ross the experience to understand how the invisible wind reacts to different shapes. What can we learn from his knowledge? Day takes you inside.

Don't forget to check out more of our Training Day by Day features.

Everyone is different

It is difficult to make a general assumption as to what is fast for a person without taking into account their mobility. That is why a bike fit is a necessary component of optimizing speed, not only in the wind tunnel but also out on the road.

DaybyDay athlete kyle buckingham gets his fit and position optimised (in case you're wondering, the bike is a 'ventum'): daybyday athlete kyle buckingham gets his fit and position optimised (in case you're wondering, the bike is a 'ventum')
DaybyDay athlete kyle buckingham gets his fit and position optimised (in case you're wondering, the bike is a 'ventum'): daybyday athlete kyle buckingham gets his fit and position optimised (in case you're wondering, the bike is a 'ventum')

Just because some are faster with a lower position, don't assume you will be

“One of the worst things to assume is getting a rider lower will automatically make them faster," Ross explains. "By dropping the front end you may lower some aero drag, but you may lose a lot of pedaling efficiency, and may not be able to hold it throughout an event.

"Getting a rider to sit low in the bike is paramount, but that does not necessarily mean a low front end," he adds. "Understanding what their range of mobility is allows us to best see what their aero drag numbers are while still pedaling efficiently.”

Working at it to be fast

You can spend all the money you want, but when it comes to race, it's the rider on top that counts : you can spend all the money you want, but when it comes to race, it's the rider on top that counts
You can spend all the money you want, but when it comes to race, it's the rider on top that counts : you can spend all the money you want, but when it comes to race, it's the rider on top that counts

Fast equipment is just a small part of the story

Optimizing your speed is partly up to you as well. Ross believes that the posture that the rider needs to remember to hold is 60-70 percent of the speed equation. But without a quality bike fit acting underneath that as a stable foundation, the position will be inefficient.

“You can have the most aero bike or equipment in the world, but if your ideal body position is not going to match with the bike or the equipment, then there will be compromises somewhere,” Ross says.

Revolution or evolution

Aerodynamic improvements can be a revolution, with the initial session being very valuable, but they becomes evolutionary as a rider further adapts to their position, creating comfort and efficiency aerodynamically. Ross says he often sees that after this initial period of time, further refinements can be undertaken and employed to find a new level.

Simulation versus real world

Ross has seen that there is a direct correlation between wind tunnel data and the real world – the reason why the top bicycle and equipment companies invest in tunnel time. “The wind tunnel testing is done in a controlled environment as this makes it easier to see small differences," he says. "We also have the rider pedal under load, which will help simulate outside riding conditions. As we go through the athlete’s tunnel protocol, and we check for repeatability, we can really understand what the rider can realistically do outside."

Based in arizona, faster offers a wind tunnel facility for cyclists : based in arizona, faster offers a wind tunnel facility for cyclists
Based in arizona, faster offers a wind tunnel facility for cyclists : based in arizona, faster offers a wind tunnel facility for cyclists

If you're serious about going fast against the clock, time in a wind tunnel may be money well spent

At FASTER, investment in wind tunnel time is summed up in an interesting way: grams of drag (a measure of the resistance) reduction divided by dollars spent. An aero bike saves 1g for roughly every US$22.50 spent.  Wheels, US$18 for every gram saved. You on your bike, in the wind tunnel in an optimized position, equals roughly $1 for every gram saved.

Do it yourself method

If you don’t have access to a wind tunnel and you still want to improve on your aerodynamic position, you can do so with the help of your power meter. One simple method, although not as accurate as the wind tunnel, is to find a venue with limited variables such as a windless stretch of road where you can test in both directions.

Complete one pass in both directions at a constant speed (remove acceleration and deceleration at both ends of the run) over a known distance (at least 500m) and record average power for the runs. Quickly make changes to your position to reduce the effect of changing weather conditions on your testing, and complete another pass in both directions at the same average speed. Compare average power over the runs to determine how much you saved.

With special thanks to Aaron Ross at the FASTER Performance Center for his insight and experience.

Ben Day started DaybyDay Coaching in 2008 to share his experience as a 13-year international professional cyclist with endurance athletes of all levels. An ex-national champion, he recently retired from racing professionally with the UnitedHealthcare Pro Cycling team to focus on delivering the DaybyDay Coaching service to amateur athletes and professionals, first time racers, to WorldTour professionals. 

In future articles, Ben Day, Chris Baldwin and new DaybyDay Coach, Jeremy Hunt, will continue to share with you methods for improving your cycling, whether mental, physical or technique related. Do you have any tricks that you use or questions for future articles? Share them with the guys on Twitter – their handle is @daybydaycoachin and join the DaybyDay Coaching community.

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