The Relentless Pursuit of Cycling Aerodynamics

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This episode, cycling aerodynamics, get faster by getting more aero.

If I could reduce this aerodynamic coefficient by about 15 watts, I’d have the record.

– Dean Phillips, on the search for 2.1 seconds for a World Record.

The Feature

Cycling Aerodynamics account for anywhere between 70 to 90 percent of a cyclist’s effort (when not climbing a steep grade).

 

Anyone—hardened pro and new rider alike—who is interested in riding faster or further has a vested interest in improving their aerodynamics. It’s that simple. Determining which bicycles, components, and positions are truly the most aerodynamic for you, however, is anything but simple.

 

Today’s show is about masters rider Dean Phillip’s quest for speed, world championships, and a world record. It’s a story about using aero testing to hunt for 2.1 seconds and ultimately adding over 3 mph or 5 km/h of speed (with no increase in power) and finally, it’s about how you can start on a similar aero journey today.

Resources

Transcript

Damian: If you were to attend any Gran Fondo, Grand Tour or local Sunday-morning group ride, chances are you’d notice the aero wave, as I like to call it, an abundance of overtly aerodynamic bicycle frames, apparel, and components on display, which begs the question: Why? Why has aerodynamics become a major priority for so many cyclists?

 

Is this about cycling manufacturers trying to squeeze more money out of us punters or is there some validity behind the growing movement to get as “aero” as possible? The short answer is, yes, aerodynamics matter, they matter “a lot”. In more practical and scientific terms, anywhere between 70 to 90 percent of a cyclist’s effort (when not climbing a steep grade) is dedicated to plowing through the air.

 

Anyone—hardened pro and new rider alike—who is interested in riding faster or further has a vested interest in improving their aerodynamics. It’s that simple. Determining which bicycles, components, and positions are truly the most aerodynamic for you, however, is anything but simple.

 

SPC Indent

 

Damian: This is Semi-Pro Cycling. I’m Damian Ruse. Today…a show about the Relentless Pursuit of Cycling Aerodynamics, it’s a story about one master’s rider’s quest for speed, world championships, and a world record. It’s a story about using aero testing to hunt for 2.1 seconds and ultimately adding over 3 mph or 5 km/h of speed (with no increase in power) and finally, it’s about how you can start on a similar aero journey today.

 

Dean: Trying to find these two seconds (3K World Record). The thing about this event (3K) is, after the standing start, it only comes down to this power to aerodynamic drag ratio, how fast you’re going on the track. So you’re making a certain number of watts and then your aerodynamic drag coefficient is what defines how much resistance you´re fighting. So, if I could reduce this CdA to about 15 watts, I´d have the record. It´s more easily said than done.”

 

Damian: This is Dean Phillips, a 42-year-old cyclist, father of 4 and bikefit business owner from Peabody, Massachusetts in the USA – and as Jim Manton from ERO Sports says…

 

Felt TA Test Clip

 

Damian: Why? Because in aero terms Dean has worked on his aerodynamic drag (which is also called CdA, but I’ll explain this in a bit more detail later) reducing it from a CdA of 0.227 in 2015 to a CdA of 0.19 in 2017. In real-world terms for Dean’s pet event, the 3K pursuit this added over 3 mph or 5 km/h of speed (with no increase in power).

 

The fascinating thing about these numbers is Dean’s size – he’s a big guy, a 1.9 m (6’3”) cyclist weighing 95kgs (210 lbs). His broad shoulders come from rowing where at 21 he was a U23 World Champion rower – moving to triathlon after ruptured discs in his lower back ended his rowing career early.

 

It was in triathlon, where Dean’s obsession with aero was born, he started competing at a professional level and began field testing his position for aero gains. As an early adopter of the power meter, he was soon field testing everything he could think of…and now riding much faster on the same power and now setting local time trial and bike course records from all the aerodynamic improvements.

 

He left triathlon after more back pain and injuries to start bike racing in 2012, going from a Cat 5 to a Cat 1 in only 2 years, subsequently winning the 2014 national time trial championship for his age group – Masters 35-39.

 

After this win, Dean’s focus switched from time trials to the individual pursuit on the track, which for a Masters 35+ rider is a 3-kilometer race. It’s a race that Dean chooses based on his power profile which told him he is a pursuiter.

 

Dean: Power profile – Pursuit rider – “Strong across 3-5 minute events. So wanted to test for that.

 

Damian: And figured it out he did, winning both the 2014 and 2015 national titles, as well as the team pursuit title. This sent him over to Manchester, England to compete in the World Masters Track Championships where he won the 40-44 age group World 3k individual pursuit title. But, and this is important but for our story, he missed out on the World Record…

 

Dean: World Championships, Manchester England. Bike got lost on way to event. Got there, qualified for final and got the jersey – didn’t get the world record. 2 seconds off the world record. Started latest chapter “aero journey” to find these two seconds. Talks about doing more testing, components, position etc. Started documenting all testing I was doing.

 

Damian: So for Dean, this is where his Relentless Pursuit of Cycling Aerodynamics started, and for us, this is also where the story starts. As Dean puts it – “all you had to do was find another 15 watts of average power, reduce your aerodynamic drag coefficient from 0.227 to 0.220, or some combination of both. How hard could that be? Famous last words.”

 

Music

 

Before we go any further, I want to address the fitness element of the cycling performance equation. You might be listening thinking – why doesn’t he just train harder or differently – let me tell you, Dean has tried everything training wise from low volume high intensity, to high volume low intensity, to intervals every day, to tempo every day, and in the end he found himself making similar power for his key events.

 

So in order to find the 2.1 seconds he to break the world record, Dean’s focus become aerodynamics. There are other things he considered (and tested) including rolling resistance, but the biggest wins would need to come from his aero position. CdA is another term for Drag Area. It’s a measure of how efficiently you convert your power into forward speed. The lower your Drag Area, the faster you’ll go for the same level of effort.

 

Let’s break it down a little more – it doesn’t get too technical so stay with me. CdA is also a shorthand for Cd * A. Cd is the coefficient of drag, in other words, the force of wind or air resistance pushing in the opposite direction to the motion of the object, in this case, the cyclist, and the bike. A is the frontal area you project, the area you’re presenting to the wind while moving forward on your bike.

 

Sit up, stand up, ride on the hoods, the drops – these present a different frontal area to the wind. In a time trial or pursuit, you’re down on some form of aerobar, and so you have an idea of what the perfect aerodynamic position is, the average amateur cyclist presents a CdA of around 0.25 – 0.3 using aero bars.

 

I hope this is painting a clear picture of how a bigger cyclist can really start with a disadvantage – it’s not just about power to weight ratios, it’s also about the Power to Aerodynamic Drag ratio or power to CdA ratio – W/m^2. The higher the ratio, the faster you go.

 

To give you some context – Let’s have a look at the values for the Hour Record or as some of the attempts were deemed Best Human Efforts. Not to derail this episode and get into the politics of the hour record but until 2014, if you attempted an hour record on anything but a replica of Eddy Merckx’s 1972 record-breaking bike (no aero bars or aero wheels) than it was called a Best Human Effort – the heyday of which was the 90s.

 

Where the flying Scotsman, Graeme Obree, built the bike he called ‘Old Faithful’ that beat the record, before being banned, then he built another bike that gave him a superman position and that gave him a .17 CdA – phenomenal for anyone let alone a guy of 1.8 meters. In comparison. Eddy Merckx and his traditional position had a .26 CdA.

 

Going down the list of Best Human Efforts, there’s Indurain in 1994 producing 0.24 CdA, Boardman in 1996 (in the superman position) with a .18 CdA – and finally a legal world record in 2015 after the UCI changed the rules – Bradley Wiggins recorded a .22 CdA – about the same as Dean’s starting point (0.227) they happen to be the same height at 1.9 meters tall. That’s where the comparison ends, though. Wiggins weighed 69kgs, 26kgs less than Dean, and I won’t mention Wiggins held his position for 60 minutes rather than 3 minutes.

 

Music

 

Once you begin to understand the potential of getting aero, whether, by equipment changes or position changes to lower your CdA, you will go faster.

 

But how can you test these changes without a wind tunnel? The traditional (and expensive aero testing ground). With a power meter and Dean is now a master at testing with his power meter, but it was a long process to get to where he is today.

 

Dean: 1999 or 2000 I had a power meter, and it wasn’t long that Jim Martin, a big aerodynamics guru who has written a number of different presentations. I saw him speak at a cycling symposium about using your power meter to do aerodynamic testing and he may have been using as early as the 1990s that involved using a runway, a flat stretch of road without cars.

 

You´d spend about an hour going back and forth on your bike at different speeds. You’d download all the power data afterward. Eventually, because of all the different speeds you used, the aerodynamic drag and rolling resistance with very different rates, you´d get your aerodynamic drag coefficient. But it was a lot of work, a lot of time. It couldn’t be that windy, passing cars. So finding a venue itself was very challenging.

 

It went to doing that from all the way back then to now using the Chung method. Robert Chung published a way to do it. We use what we call a half pipe. Just a hill. You go down and up the hill, turn your bike around and go the other way, so you’re continuously going up and down a hill, back and forth.

 

The software, Golden Cheetah, free to download I believe has a function called aerolab that does all this for you. I can go out there, it’s much easier to find a venue I go early morning before cars, usually a Saturday morning.

 

Now I can test 6 or 7 positions on some days. Like being in the wind tunnel for that whole hour. You get addicted to it, over the years looking for new gains and you gradually find a faster and faster position, which truly brings me to where I am today, with the most aerodynamic position for someone my size.

 

Damian: As Dean mentions, testing can be a lot of work not only because of the conditions but also because the sheer number of things there are to test. Dean has field tested about 500 setups at this point so his protocol and results are pretty tight.

 

Countless trips in full aero-get up, we’re talking about changes such as:

 

Hand position (thumbs forward)
Visor position
Aerobars placement
Skin suits
Wheels
Various length stem arrangements

 

Then packed away and stashed to test again and again.

 

Dean: Field testing, positions skinsuits, helmets… head, arm hand positions…

 

Damian: It’s not all smooth sailing, though. Some days you may find no gains, as Dean explains.

 

Dean: I’ll go out and I’ll spend hours testing…some days it can be very challenging to find those gains.

 

Damian: With all this testing Dean did find some gains and at the 2016 track Worlds in Manchester, his total CdA was 0.221 a nice jump from 0.227, but did he have enough for the World Record?

 

Dean: I knew I was in the ballpark of a faster aero position…for my second rainbow jersey in that event.

 

Damian: So while he’d collected that 2nd rainbow jersey he was short of the world record time, this time by less than a second – a blink of an eye. Ouch! How did he feel about missing it by so little?

 

Dean: I was very happy with it…and that was that.

 

Damian: Indeed, that was that – but of course he kept going, straight back into testing. This time, though, some indoor velodrome testing – that had some surprising results.

 

Dean: Then an opportunity came…more of a wash.

 

Damian: Interestingly the setup he landed on was an older bike, a Cervelo T4 with Zipp wheels.

 

Dean: I believe it was a .005…to test it last winter.

 

Damian: That testing session alone lowered his CdA from 0.221 to 0.211. But that wasn’t it for testing, or aero gains because Dean had a once-in-a-lifetime opportunity to test the Felt TA FRD with Alphamantis and Velonews – the Felt is a $26,000 bike! Now up until this point Dean has gone from 0.227 to 0.221 over 2 years and a lot of tweaking – the number he was about to hit was next level.

 

Dean: So Velonews was testing…with drag that low.

 

Damian: Let’s put this perspective quickly – if you remember back to the hour records or best human efforts I talked about earlier – Chris Boardman set a best human effort in the superman position with a similar CdA – Boardman is 1.75 m (5 ft 9 in) tall and weighs 70 kg (154 lb; 11 st 0 lb).

 

In other words, a pro cyclist at the time, who is shorter by 15 cm and lighter 22 kgs – in a crazy and illegal position set the same CdA as Dean. Wow! In real terms, this is a savings of over 40 watts at his 3km race speed – about 5 second over 3k. That would surely help him set a new world record, but here’s the punchline…

 

Dean: That was a tremendous gain seeing how fast that bike…my hands on one.

 

Damian: So back to the Cervelo T4 – and back to a CdA of 0.211 for his next record attempt which happened a couple of months later in July, 2017 where Dean was given an opportunity to make a special trip to a velodrome at altitude in Mexico.

 

Dean: and an opportunity came up in July…so it worked out well.

 

Damian: …and so on July 15, 2017 Dean Phillips went for the UCI Masters 40-44 3K World Record – Did he get it? Listen in as we catch Dean talking us through the last few laps of his World Record attempt…

 

Dean World Record Clip

 

Damian: So there you have it – the relentless pursuit of cycling aerodynamics paid off for Dean – with World titles and that all-important World Record.

 

There you have it a journey through the aero journey…maybe it’s been enough to inspire you to find some gains of your own – and not just in an aero tuck. I’ve got riders I coach talking about once they are aware of their best positions, they are reducing times in all sorts of scenarios. If testing interests you I’ll put up some resources on this episode’s page which will live at semiprocycling.com/dean and also get Dean to jump in the comments on that page, so fire your aero testing questions at him.

 

Going forward, as noted by prominent sports tech blogger DC Rainmaker “Aero is the biggest new potential area for the next year.” He believes they could be like power meters all over again…if done right. And I tend to agree – with a smattering of aero coaching services and products on the market, it’s an area ripe for expansion. And something I will dig into in another episode because after all how cool would a live CdA number during your rides – yeah totally cool.

 

SPC End

 

If you are new to Semi-Pro Cycling, check out the back catalogue of shows on all aspects of performance at semiprocycling.com or sign up for the Weekly Workout Stack – The guide that shows you how to structure your training week and use your training time more effectively, and I’ll also send you a best of our episodes straight to your inbox.

 

Alright, well, I’ll be back in 2 weeks. Thank for listening

 

The Facts

Hosted by Damian Ruse

Produced by Ciarán Mac Parland

Sound Engineer: Satyr Productions

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