The Aero Makeover

The Aero Makeover

My life is full of competing desires. I want to be a good father. I want to drink wine (or beer) with dinner. I want to stay married. I need to write on a daily basis. And I love riding my bike fast. The number of hours I’d like to do each of those every week works out just fine until I factor in six hours of sleep per night. The plan actually goes to hell at four hours a night.

I’m simply not going to get as many hours to train each week as I’d like. The weeks where 18 hours on the bike and soft-pedaling a 53×19 uphill were routine are receding like a shoreline in a storm. If I get 18 hours on the bike now, it’s because I’ve taken a vacation from at least two major responsibilities, and I’m likely to pay once enough blood is flowing to my brain again for me to think straight.

With due regard for the pressures of fatherhood, marriage and career, I don’t want to stop riding my bike as fast as I’m able. I recognize that’s a bit like saying, I can get a great shot of that water buffalo once I move the lion off of it. Making a bike lighter, if you follow the math, won’t pay much in the way of dividends, and lifting weights at the gym only starts to pay off once I stop lifting, so neither of those will yield the benefits I’m looking for. However, my experience with aero equipment over the last few years has told me that I can reasonably expect to pick up at least one cog’s-worth of fitness by doubling down on aero.

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Normally, my story ideas don’t require much in the way of selling someone else on my escapades. I don’t have to write queries the way I did when I was freelance, or pitch my editor on what a terrific idea I have, what with me being the editor and all. But this occasion required some help.

I placed a call to one of my contacts at Specialized. The question was, would they be willing to allow me to visit their wind tunnel for some testing guided by questions I had? When I told them just what I had in mind, they gave a ready yes. Cool.

My idea was simple: I’d pretend I worked for the cycling equivalent of a women’s magazine and we’d do a makeover, just this one would be for aerodynamics. Kidding aside, when you encounter stories about pros going into the wind tunnel, the goal is to optimize equipment choices and position for the greatest possible gains. They change their position to achieve greater aerodynamic efficiency.

Um hello? I may not be old yet, but I’m getting old, so the last thing I want to do is mess with my fit. Any changes I make to my fit are meant to optimize comfort and efficiency. What if you used the wind tunnel to figure out what you can do to be faster without making yourself uncomfortable? I’d much rather give up some time and have a position that I can pedal in for a few hours than a position that renders me ninja to the wind but I can only maintain for 45 minutes.

That no one within Specialized had considered this and no one they worked with had mentioned it shocked me. It seems such a no-brainer, but maybe this is just another example of how I always end up at the shallow end of any given bell curve.

DSC01987 copySpecialized’s Cameron Piper walked me through how the testing would be done. I needed lots of instruction.

Slicing the pie
Because I wanted something that was direct in its analysis and appeal, and also because I knew I’d have a piece of one day to do all the testing, I suggested we analyze three different setups.

Test one was simple; it was as old school a setup as one might reasonably encounter today. I would don a traditional pair of bibs, a relatively loose-fitting jersey, an old helmet and ride my steel Bishop with a Dura-Ace group and box-ish rims. The cherry on top was that for five months I’d let the hair grow on my legs.

Test two would be the low-hanging fruit. I’d shave my legs and swap out my helmet for a Specialized Evade and trade my kit for a Specialized SL Pro jersey and bibs, a pro-fit kit. This was an upgrade any cyclist could make for less than $600.

Test three would be all-in. I’d keep the kit and add a Specialized Venge plus Roval CLX 60 wheels. We did our best to accurately replicate my position on the Bishop. According to the tape measure, we were off by less than a centimeter overall, but more importantly, in video analysis, my position on the two bikes looked identical. Test three was as aero a solution for someone riding on the road (short of going with a TT bike) as we could manage without going to other suppliers or geeking out over each and every detail. The point was to back up and look at the bigger picture.

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  1. Marc

    You don’t say what the windspeed was during the test. As a middle-aged man of sketchy fitness who only touches speeds of 25+ with the help of a downhill or tailwind, I always wonder what aerodynamic benefit I could expect. Since I believe I learned somewhere that drafting, for instance, doesn’t really kick in till 20 mph or more, Ive long assumed that, at my usual 15 mph pace, I don’t need to worry too much about aerodynamics. True?

  2. Author

    Marc: The windspeed in the tunnel was 30 mph, but I didn’t go into that because it’s irrelevant to the result. So here’s the thing: Supposing I’m riding into a perfect headwind with my shaved legs, pro-fit kit and aero helmet; I’m going to save 73 seconds over the non-aero setup (over 25 mi.) no matter whether I’m riding 20 mph or 35 mph. As an increment of speed, riding at 15 mph your gain will be tiny, but you’re still going to recognize the same overall time savings as someone going faster. So while aero equipment might seem irrelevant at 15 mph, speed is a matter of incremental gains and those increments will even help at low speeds.The thing about riding at higher speeds is that you’re much more likely to actually feel the gain.

  3. Les.B.

    I would love to have one of the wind tunnels in my back yard. Being the geek I am I would do all kinds of data gathering. With the requisite data set, one could make a 3-dimensional graph of CdA vs Yaw vs speed for each setup. One could position another cyclist in front of the test vehicle and measure the reduction in CdA. I still don’t know if aero wheels or aero frame make more difference. With my backyard setup that would be cleared up. And how about air temperature? I don’t know if I’m imagining it, but I seem to descend faster in cool weather. One could go nuts with this stuff.

  4. Hoshie99

    Yep, that all makes sense. A useful exercise so thanks for doing it. I wonder what benefit the wheels were for the full aero set-up? If it was half the last step of gain, you’d essentially get 3/4’s of the aero benefit by wearing race fit clothes, an aero helmet and an aero set of wheels and having shaved legs. It’s amazing what a set of HED, Zipp or a similar set of aerodynamically designed mid depth clinchers can do….

    In contrast, spending money on a new road “aero” bike with a poor fit, wearing a loose jersey or non aero helmet – might as well save the money….


  5. Rod

    Les B. -if you have the time and inclination, there is a lot of material available on “Chung on a stick” and “aerolab”, a method for on the bike aero testing.

    As for descending faster when colder – maybe, but unlikely. Air drag decreases with higher temperatures, mostly due to reduced density- that’s why they make velodromes warm.

  6. Tom in Albany


    I couldn’t help but notice you stating you find yourself at the shallow end of a bell curve. I also note you stated you slept through math. There are two shallow ends of a bell curve. Make sure you claim the proper end!

  7. Jim

    Thanks for quantifying this. Over the past two seasons I have made all the changes you did except for the aero helmet. That is on tap for this season. All of the changes starting with the clothing and up to a Venge with FLO 60 wheels have made it easier to hang with my regular group and to continue to take strong pulls on the front even though I am now on Medicare. One more suggestion for you to implement with your set up: Use Conti GP 4000 S II tires with latex tubes. These are directional tires with good aero properties and very low rolling resistance as well.

  8. Author

    Everyone: Thanks for your comments. Regarding the question of how much benefit aero wheels present vs. an aero frame, the answer is a moving target. In this particular instance with the Venge and the CLX 60s, my suspicion is that the wheels provided more than 50% of the aero benefit in this setup. This backs us into one of the more interesting implications of the test. While I want to make it clear that I have a great deal of respect for the work that Specialized has put into their products, there are both frames and wheels on the market that are faster than the Venge and the CLX 60s.

    Tom in Albany: Two sides to a bell curve? I was definitely asleep. Is one side worse than the other? I’m probably on the worst side. FMBC.

    1. Randy Cox

      What is faster than the Venge. I have your same setup and have had allot of other high end bikes and I think my Venge blows them away. Also what do you think of the Bell Star Pro Aero Helmet.
      Thanks Randy

    2. gregorio

      One of the bikes that has better wind tunnel numbers than the Venge would be the Felt AR2.

  9. Greg Thompson

    I asked Mark and Chris at the Specialized tunnel about fit considerations, and they told me that when they work with sponsored athletes to improve their position, they have a fitter in the tunnel the whole time to make sure any aero changes don’t affect the rider’s biomechanics, e.g. if dropping the bars 2cm results in a 20 second time gain, but the rider can’t hold the position, they find another way to get free speed.

  10. Jan

    The two sides of the bell curve aren’t necessarily “better” or “worse” depending on how you define those. If what you’re talking about is height, then Wilt Chamberlain is on one side, and Willie Shoemaker on the other. Both were great athletes at their sports, but neither would have been on the “good” side for the other sport.

    This is fascinating. But I have to confess that if I could get out on my bike more, lose some weight, and that sort of thing, I’d make way more than marginal gains!

    1. Author

      Jan: I was making a joke. I didn’t actually sleep through math, either. And they didn’t actually speak slowly to me.

  11. John Kopp

    It does not surprise me that wearing a more aerodynamic helmet and clothes will be a big improvement. The frontal area of the rider is five times more, or greater, than the frontal area of the bike. I assume that most of the improvement going to an aero bike was the wheels. The wheel is the larger part of the frontal area, and the turbulence caused by the spokes can be significant. It appears that the gain in speed is 2 to 4 percent. It would be nice to know what the gain would be in just changing the wheels. Nice to see these results. Thanks Padraig.

  12. Dan Murphy

    I’m curious how many people really care about aerodynamics.

    I’m not saying this to be a dick or to rain on your parade. I’m a geek and understand people’s passions, especially when it comes to gear, so I understand why people would go thru this process. I’m just curious how many people really care.

    Hey, I’m turning 61 next week and stopped worrying about how fast I ride a long time ago. My rides have definitely gotten a lot more casual in the last 10 years and I still love getting out for hours at a time.

    Cool stuff, though.

    1. Waldo

      Seven years ago, I refused to ride with groups because they stopped to wait for dropped riders and lingered at coffee shops. Now, every ride of mine has a mandatory coffee stop.

  13. kurti_sc

    I know the guys at Roval are putting a lot of time and engineering into their wheel designs. It shows in these results.
    Their wheels look much improved over the last 10 years.

  14. steve

    I didn’t sleep through math and understand drag to follow the rule of inverse squared. In other words, double the surface area, quadruple the drag. One could also double the speed to quadruple the drag. All I’m saying is that drag matters more for those riding fast.

    1. John Kopp

      Drag is directly proportional to e cross sectional area, so double the area and double e drag. But you are correct about speed, double the speed and quadruple the drag. If you’re concerned about power, then you have a cube relationship to velocity. Double the speed and it requires eight times the power.

      I would much rather sit on someone’s wheel. Drafting is a lot easier. I learned this on a Minnesota Paul Bunion Ride. The group made the first 100 miles in about four hours. But after the lunch stop, it took me almost ten hours for the next100 miles back. Mostly riding alone. This was 30 years ago, and am not sure I could keep up in the pace line now.

    2. Rob Pickels

      Granted the gains are greater at higher speeds, when you multiply by the additional time slower riders take to complete a route, you realize gains are had by all.

      Whether those gains are important to an individual is up to them (regardless of ability), but you cannot deny they exist.

  15. Waldo

    A couple of comments:
    1. Unless I am attempting to set an athlete hour record under the pre-2014 UCI rules for the event (not happening), no way in hell am I going to ride in the drops for an hour.
    2. Who wants to spend “more time at the front of the group ride?” That’s just preening. 🙂

  16. peter lin

    Specialized does have several videos comparing shaved legs and arms, different kits, non-aero vs aero bikes and quite a few more. Are they planning to post videos of your time in the wind tunnel?

  17. Bikelink

    Thanks for the great ‘real life aero upgrade’ info. This fits in with other tests that specialized and others have done in my mind…that a snugger jersey can save as much time as $2000+ wheels, and the overall effect of all of this is much smaller than being in a little better shape (e.g., rider with ‘traditional’ setups kick my butt frequently when I use to race with the ‘full aero’ setup). Re: use of aero I find that most group rides are only hard on the hills, so for most it may mater very little. For fast group rides on the flat, or racing (where there isn’t a big hill that’s a decider) it helps hugely.

  18. Neal

    Very good article and thanks to you, and Specialized, for making it happen. It brings a lot of the elusive aero mystique to the layman cyclist.

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