Beat Wind Resistance

The air around you has much more of an effect on your time than you might think


Posted: 18 November 2009

Think about this: you could cut more than a minute off your race time by changing your wheels and 30 seconds more from changing the tyres. You could shave 70 crucial seconds with new handle-bars, 35 with new forks and a remarkable four minutes by optimising your body position. That's a potential improvement of over seven minutes, and 100+ places, in an Olympic-distance race - all from improving your aerodynamics. 

An improvement of seven minutes might take two or three years of hard training to achieve and yet a couple of weekends spent fine-tuning your bike, equipment and riding position could have a similar effect. A better understanding of how to reduce drag on the bike could very quickly turn you from an also-ran into a contender, because, as any aerodynamics expert will tell you, drag sucks.

If you ignore the effect of factors such as big hills and rider weight, your speed on a bike comes down to two things - how hard you pedal versus the drag of air resistance. It's amazing, then, that most triathletes will cheerfully devote hour after punishing hour of their lives training to improve their power, while almost completely ignoring the possibility of reducing air resistance. 

Multiple British Time Trial Cycle champion Michael Hutchinson was different. Realising the huge importance of being streamlined when racing, Hutchinson went to the trouble of building his own wind tunnel several years ago, using high-tech equipment such as "some bits of hardboard, a big fan and the kitchen scales". He then tested a carefully sculpted Plasticine model of himself in his DIY wind tunnel. 

Spectacular Success

It's perhaps no great surprise that the results were less than perfect - the only race he did in his 'Plasticine position' was a disaster. Hutchinson's aerodynamics experiments didn't end there, though; he has since spent time wind-tunnel testing and has also tested various riding positions at a velodrome, using a power-meter. By applying hard work, intelligence and ingenuity to reducing drag, he is now widely recognised as having a highly aerodynamic riding position. It's this combination of hard work in training and diligence in reducing drag that has enabled Hutchinson to dominate British Cycle Time Trialling in the spectacular way that he has.

Tunnel Vision

Professional cycling teams and national bodies like British Cycling invest considerable time and money in wind-tunnel testing because they recognise the significant benefits. Proper wind-tunnel facilities accurately test the effect that changes in body position and equipment have on aerodynamics and, ultimately, cycling speed.

Unfortunately, wind-tunnel testing facilities are few and far between. Mainly based in the USA, these facilities are well equipped but too expensive for most triathletes. However, 2008 saw the introduction of two new wind tunnels in the UK, in Southampton and Swindon. Triathlete's World squeezed into its tightest Lycra and decided to find out more.

The testing at both locations is run by Simon Smart of Velo Science, who developed the Drag2Zero testing concept. Smart is a keen cyclist with a background in testing Formula One cars, and he also helped to design and develop the Team Columbia Giant prototype time-trial bike used in last year's Tour de France, so he knows a thing or two about reducing drag: "There are two main ways cyclists can reduce their drag," he explains. "The first is to improve their bike and the equipment on it. The second is to focus on the rider, their clothing and their position on the bike."

Feeling the breeze

Sitting on my bike in the wind tunnel makes me feel like I'm an extra in an episode of Doctor Who. A brightly lit white tunnel disappears around a bend in front of me as I peer through a square window at Smart tapping away at his two laptops, while the wind tunnel blasts a wind against my body. With a 40kph wind hammering against me, I should be able to actually feel and hear when I am in my most aerodynamic position. 

I concentrate on the sounds and the feeling of the wind, and make tiny adjustments that reduce the volume and turbulence. But the testing is far more precise than just going on 'feel'. Smart adjusts my head position, then switches on the wind tunnel, records the drag, switches off the wind tunnel, adjusts my position once more and starts again - the process is repeated several times. After several hours my legs ache and my neck is sore, but Smart provides me with a wealth of information that could mean the difference between a good triathlon and a great one.

Simple solutions

What is clear from the testing is that there is no single body position or piece of equipment that fits all. Every triathlete is unique and requires a unique solution. I tried several different aero helmets, for example, but it was my own Louis Garneau helmet that came out best for me because the fit was snug and happened to closely follow the contour of my back. The result would not be the same for everyone else. Smart was quick to point out that another potential timesaver, particularly for women, is tucking away the loose hair or ponytail that can protrude from your helmet.

The results of the test suggested several small changes to my body position that would hopefully result in a significant improvement. Surprisingly, my optimum position involved moving my handlebars higher at the front than I had been used to. However, another cyclist who was also being tested at the wind tunnel needed to have his handlebars very low to achieve his optimal position, highlighting the fact that there is no correct position that suits everyone. As Smart says, "Reducing drag is not all about being as low as possible at the front. It is a combination of your frontal area and also the shape you form on the bike."

While the benefits of wind-tunnel testing are obvious, it is a pricey and complex procedure. At £225 a pop, testing is not going to be within everyone's budget and so it may be most suited to experienced, committed triathletes looking to trim every last second from their race time. Your money buys two hours of testing, which is enough time to fine-tune your existing position. It would take far longer, possibly days, to get the full Lance Armstrong treatment, calculating your best position from scratch, along with each component on your bike and every piece of equipment.  


No excuses

I'm too slow to worry about drag

The effect of drag from air resistance is not as great when you're riding at slower speeds, so many triathletes think they can ignore aerodynamics. They believe they're too slow for an aero helmet or aero wheels. This is a mistake. Drag is greater at higher speeds, but there are still benefits from reducing drag at lower speeds. Wind-tunnel studies suggest that a triathlete who rides at just 100 watts for 25 flattish miles would save up to nine minutes by fully optimising bike, equipment and body position compared with riding on a standard racing bike without aero bars. Nine minutes! You would probably need to invest in new equipment and spend some time developing your riding position, but still, nine minutes!

I compete in hilly triathlons so I don't need to be aerodynamic

Riding uphill in a low-profile position on aerodynamic bars and deep-section aero wheels can often feel uncomfortable and sluggish. On hills with a gradient greater than around six per cent, the benefits of being aerodynamic are outweighed by lower speed and loss of comfort. However, while you don't gain much from reducing drag going uphill, you don't lose much, either. So when you reach the summit of the hill and start descending, the benefits of aerodynamics come into play again. Unless the course is very hilly, you should still consider aerodynamics as being important in undulating races. 

I can't afford a new aerodynamic bike

Reducing drag needn't mean reducing your bank balance. Remember that your body meets the most air resistance, not your bike. Even something as simple as wearing tight-fitting clothing will make a difference. Consider anything that flaps in the wind as a set of unwanted brakes. Another free way of gaining a little speed is to remove anything unnecessary from your bike. Small objects such as bike computer sensors, spoke magnets, bottles and light-brackets are all at the front of the bike and they create velocity-sapping drag. 

However, the most significant area for potential gain without having to hand over your hard-earned cash is optimising your body position. Start by setting up your bike on a turbo trainer, with mirrors in front and to the side. Make tiny adjustments to the saddle (backwards or forwards), saddle height and handle-bar height, and then hop onto your bike and observe the differences in your body shape and frontal area. Comfort is obviously a big consideration, so don't do anything too drastic. It's not a scientific method, but it will give you some idea of what you can do. Be sure to note your original setup should you wish to return to it.

If you're in the process of buying a new bike, consider sacrificing expensive lightweight gears and brakes for an aerodynamic frame and wheels. Components such as gears and brakes can always be upgraded later.


Feel the force

Follow these 10 simple tips to become more aerodynamic without the cost of wind-tunnel testing:

1 Use a time-trial/triathlon bike - they have steeper seat-tube angles, helping you to achieve a more streamlined position, while also allowing for superior comfort and power application.

2 Use a well-fitting aero helmet that closely hugs your back.

3 Remove all excess computers, spoke magnets, lights and bottle cages from your bike.

4 Tuck in any loose hair - really, it works.

5 Wear tight-fitting Lycra; every little helps.

6 Switch to aerodynamic time-trial aero bars and brake levers.

7 Set up your bike on a turbo trainer, with mirrors in front and behind you. Make tiny adjustments to your setup and observe how they affect your body position, frontal area and overall shape.

8 Take up yoga classes. The extra flexibility gained, especially in the lower back, might help you achieve a more aerodynamic position on your bike.

9 Consider using deep-section aero wheels.

10 Have a professional bike-fitting. This will enable you to find a bike-fit that optimises power, comfort and aerodynamics.



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