We chat with Body Rocket founder Eric DeGolier about the new system that promises triathletes and cyclists live, wind-tunnel-quality data on every ride.
Body Rocket is a prototype system comprised of a trio of force-measurement devices situated on a bike’s stem, seatpost and pedals that collect data on the fly to help athletes become more aerodynamic.
It’s like having a wind tunnel you can take anywhere and that’s an exciting prospect for any triathlete – the potential to take aerodynamic testing into their own hands to become faster for the same, or less, effort.
To find out more about this potential game-changer, we talked with Body Rocket founder Eric DeGolier, a design engineer who previously worked for Trek Bicycles, PowerTap, and CycleOps and came up with the concept for Body Rocket while training as a tandem pilot for the 2004 Paralympic Games in Athens.
How does Body Rocket work?
With its ability to give you instant, wind-tunnel-quality feedback on the aerodynamics of your position as it changes, Body Rocket seems almost too good to be true – so we started by asking Eric to demystify just how it works.
“It does sound like the magic, doesn’t it?” laughs Eric. “It really goes back to how a wind tunnel works and people’s understanding of that. I think a lot of people think that a wind tunnel is figuring out your aerodynamics, measuring wind speed. Well, it’s true, they do matter. But what’s really important is that wind tunnels measure drag force. Your whole bike – and your body on top of it – is bolted to a sensor underneath the tunnel that you don’t see. It’s simply measuring the horizontal force or how hard the wind is pushing on you and your bike.
“we’re looking at how hard your bike is pushing you through the wind”
“So for us, the challenge was how do we do that in a way that allows the bike to roll down the road and doesn’t have to be bolted into the wind tunnel. And if we could do that, then you could have all those same accurate, repeatable measurements, but out in the real world.
“What we’ve done is taken that measurement of drag force from underneath the bike and integrated it into the bike. That means we’re looking at how hard your bike is pushing you through the wind. The real challenge here is, is that 80 percent of this is your body and that’s what we’re going to be telling you about. We’re looking at you, your helmet, your skin suit and your overshoes.”
Athlete-focused CdA
When measuring total drag, you’ll often hear the term CdA (coefficient of drag multiplied by frontal surface area), as well as yaw angle – the angle that results from the relationship between wind direction and the direction you’re travelling in. It’s this latter factor and how it affects drag that Eric believes Body Rocket can give a great deal more insight into.
“If you’re going to buy a bike or a set of wheels, you’re looking at a plot of CdA across a bunch of yaw angles. But when we start talking about athletes, we just talk about them like they’re a single CdA, which is nonsense. But it’s a reflection of the tools that we have.
“If you go to a wind tunnel, it’s quite expensive. But if I’m going to make a bike and sell 10,000 of them, I can spend 10 times as long measuring CdA at every single yaw angle. Most athletes don’t have as much time and money as a bike brand, so we just don’t talk about it in those terms, but we should be able to, and we will be able to with Body Rocket.”
A new way of testing aerodynamics
While Body Rocket is still heavily in development, its potential is clear when thinking about its practical applications for triathletes.
“It’ll be a little bit different to how you use a wind tunnel now. Instead of doing a five-minute test in one position then a five-minute test in another position, with Body Rocket, you’re more likely to go out and do 45 minutes or an hour in a position on a range of different roads. This means you can collect your data and define that position across a range of yaw angles and also a range of different speeds.
“Our bodies aren’t ideally aerodynamic, so your arm and leg will trip between laminar [smooth, constant airflow] and turbulent [chaotic, unstable airflow] flow at different stages. And that, ultimately, means your CdA is different at 20mph than it is at 24mph. With 45-minute tests, we’ll be able to paint a whole picture of what that means for your CdA. Then you could do that across a bunch of different positions and you would understand what position is the best.
“We expect there’s going to be a new language in how we talk about this. You’re going to have a best crosswind position and a best headwind position and they’re not going to be the same. You may have a slightly different position for different speeds as well – if you’re on a flat course and you think you’re going to average 40km an hour or you’re on a hilly course and you’re going to average 30km an hour, you may set your bike up slightly different to take advantage.”
Body Rocket for Ironman athletes
Being out on the course for so long and at varying speeds, Ironman athletes are a particularly interesting case for the new technology.
“As we fatigue, we’re less and less likely to be able to hold that good position. And so, if you think you’ve found the best position, you’re going to need to go out and do an Ironman-duration ride to understand if you held it the whole way or if you didn’t, where you lost that. So your ability to hold a position – your ability to put up power in a position – we will be able to bring that all in.
“But if you’re doing an Olympic course, you may have a different position than you have for your Ironman. Some people are doing that today, but it takes a lot of testing and a lot of time to do it. If you’re just doing it as a matter of course during your training, you’ll be able to learn a lot more without the inconvenience of having to go and do specific testing in a wind tunnel.”
Another way Body Rocket could change Ironman racing is pacing. Best Bike Split has been widely adopted by performance-driven triathletes seeking a second-by-second pacing strategy for riding with power. But with Body Rocket, computer modelling and guesstimates could be replaced with hard data.
“While there are pacing strategies that you can use that will help you, they make an assumption about your aerodynamics. You can’t tell them what your CdA is and they’re assuming it’s the same the whole way through the course. We should be able to add to those models to help athletes get better information. Live pacing is another thing that could potentially be on your handlebars, letting you know what your target wattages are all the way around the course.”
Data readouts – on the fly and post-ride analysis
Speaking of data on your bars, riders using Body Rocket can expect a wide array of on-the-bike data as well as plenty to analyse (or for their coach to analyse) after riding.
“It’s going to be very much like a power meter. There’s going to be value in being able to see it in real time on the bike and there’s going to also be a lot of value in being able to analyse hours and hours of it afterwards to understand your characteristics and what you’re capable of.
“CdA is the number we talk about and I think we’re definitely going to start with that. We’ll also want to let you know the yaw angle of the wind that you’re in. Because if you have some historical data that says you’re better a little bit further down on your aerobars in a crosswind, you’ll be able to see that and adjust your position accordingly.
“I think there might be some value in looking at the amount of power being dissipated too. So, say you’re putting out 350 Watts and I can tell you that 300 is going into the aerodynamics of your body, just simply looking at that proportion may be of some value in real time as well.”
Body Rocket pricing
“It’s a little bit hard to compare [to the cost of a wind tunnel session] because we’re talking about a product that’s going to stick with you,” says Eric. “We’ll be at the cost of a very expensive meter and that’s about as close as I can nail it down right now.
“If you look at wind tunnel time as costing, let’s say on the cheap-end that’s £500 an hour, you would be able to gather more data in a long ride on your first day with Body Rocket, so basically you’d be able to pay it off in your first day if you want to look at it in that sense!”
Body Rocket is also hoping to provide access to their products for those who don’t want to invest in the full setup.
“We will be working with coaches and fitters as well so that if you just want the one-day testing – a sort of wind tunnel experience – you should be able to go to someone who has our equipment.”
When does Body Rocket launch?
Body Rocket was recently validated at the University of Southampton wind-tunnel, the results showing the system to be accurate within the wind tunnel’s own margin for error.
“It’s a massive relief to get some wind tunnel results and have a real thing that we can take around and show people that vision of where we want to go,” says Eric with a grin.
With wind-tunnel validation complete, Body Rocket launched privately on the CrowdCube crowdfunding platform, seeking £80,000 of investment – a total reached within hours.
“The response has been amazing! It took us just over four hours from sending out an email to people who had expressed interest, to hitting our funding target.” Since then, the total has soared past 160 percent with over 160 investors taking an interest in the company.
With backing secured and development continuing apace despite the current complications of the global environment, Eric is looking ahead to turning the prototype into a saleable product as enlisting the help of some professional triathlon ambassadors.
“We’re looking to be working with some top-level triathletes by the end of this year. Then next year is all about building that commercial product because the prototype we have is not something you want to have in your race bike! What we’re launching will be significantly reduced in size and weight so that we hope athletes will find it valuable enough to keep on their bikes for race day.”
So, how soon can triathletes look forward to taking control of their own CdA?
“We’ll be announcing the final product at Eurobike 2021 and then it should be available for the 2022 season. We’ve been beavering away at this for a couple of years and if it doesn’t change the sport, I’ll be disappointed.”
