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U23 UCI Rider George Gray - Marrakech Case Study

Updated: May 2

A man cyling in an aerodynamic position
George Gray testing the Body Rocket system in Marrakech

April 2023 - Marrakech, Morocco


Name: George Gray @george.sg26

Experience: U23 UCI Rider

FTP: 380W

4km Individual Pursuit PB: 04:26

Specialty: Time Trial, Road Race Breakaway


  • Validate data from Gran Canaria and velodrome testing sessions

  • Achieve noticeable gains for a test rider

In early April, we headed to Marrakech, Morocco, in search of more reliable and consistent weather in which to test the latest iteration of the Body Rocket system out on the road.

Marrakech was primarily about validating all of our learnings from our recent Gran Canaria trip. Then, with any time we had left, we intended to get our test rider, George Gray, faster for his upcoming time trials and pursuits. A seemingly inexhaustible asset to the team, George laid down almost 400 km in an aero position for us over the course of the week!

We got through all of our validation testing in the first few days, and were able to show repeatability to 0.004 CdA, which equates to about 2.5% margin of error. This is a little off our velodrome test results but it’s a great start. We expect that it will get better with some of the hardware upgrades we have planned throughout this summer.

Our live Garmin experience had received a few upgrades ahead of this trip and this was the first outing where we'd consider it to be fully functional. We didn't know what to expect, having thought we'd spend most of the trip finding just how long we’d need to average the data, for it to make sense to a rider. Heading into testing, we expected to end up needing around 20 seconds (our ultimate goal is 15 seconds) as we're not aware of any competitor achieving results below 60 seconds on their devices. Instead, what the riders saw was pretty incredible!

With our default 6 second average, George was coming in from each test, confidently knowing whether it was faster or slower than the previous one, before we could even run the data.

Unfortunately, due to a wire coming loose on our prototype, we lost much of our data from one of the test days. This had an impact on our ability to further improve George’s position but even with that hiccup, we were able to make some significant gains. Fortunately, this hardware is being upgraded to our next generation designs over the next few months.

Interestingly, another athlete who joined us as a guest rider for a day, was able to see his CdA shoot up every time he looked down at his computer and stuck the tail of his helmet in the air.

That was really powerful for a few reasons.

Firstly, it means we're already able to drive behavioural change on the bike. See your bad habit and stop doing it. The next obvious step would be to reposition his bike computer so that he can see it more easily without looking down. Also, in the past we would have encouraged a rider to move away from an unstable helmet like this, but, looking at the data this time, seeing and accounting for the spikes, we were able to conclude that his average CdA was better in the unstable helmet, meaning it's already his fastest choice.

Being able to identify both behavioural and equipment improvements in such a short testing period is a huge leap closer to our goal of making aerodynamics more accessible to all riders. This also means our live CdA experience is officially a thing now and it's already changing how we test as now that a rider has some real perception of what's going on out on the road and what they can do to improve it, we need to be even more aware of not letting that influence any baseline testing.

The Tests

Testing began with a baseline run of 3 laps at race pace using George’s standard position, to give us a reference point. From there, we trialled various adjustments to his position, including changes to bar angle and height.

Throughout the testing period, we tried out 3 different helmets to see which one was faster for George in the relatively still conditions on the selected roads outside of Marrakech. Winds were 2-3 mph with yaw mostly under 5 degrees.


These adjustments meant that we were able to take 25 Watts off George's baseline position at his individual pursuit race pace. This equates to 9 seconds saved in a 4k pursuit, pushing his average speed from 53.3 to 55.2 kph

We're looking forward to having George back again soon to continue working on his position and equipment selection.

The Rider Experience

‘The week of riding for Body Rocket in Morocco was an invaluable experience for me. Not only was I able to achieve a substantial gain in terms of my aerodynamic position, I was also able to see my CdA change in real-time. I believe this kind of tool will become essential to riders, as it allowed me to maintain a consistent position.

I found the live CdA readings particularly useful during testing as it allowed me to maintain a balanced focus on power and aero position during riding, ensuring that an increase/decrease in one didn’t affect the other. I was surprised by just how much data the Body Rocket system identified, measuring data such as the pressure on the bars and saddle, and how this actually differed between the Cadex and the Trinity test bikes. I was also really interested to see how different helmets could cause such drastic changes in CdA, and found it was particularly useful for me in choosing the most efficient helmet going forward.

The system felt relatively easy to use, as the more complex data was saved until after the ride, meaning I could simply focus on one number (CdA) in testing. Most of the more complex data graphs produced after testing were easy enough to use, however some definitely had to be explained to me. The results lined up pretty well with my expectations, but they also really showed me how even though certain helmets are considered faster in general, they were not always faster for me.

Once commercially available the Body Rocket system will have huge benefits for the average rider, allowing them to decrease their CdA in real-time, whilst also seeing a biomechanical element. This would then mean the rider could increase their speed with no increase in effort or sacrifice of comfort on the bike, something many everyday riders experience in pursuit of the marginal gains over their riding friends and competitors.

I would definitely be interested in buying the Body Rocket system as a consumer. I think that for those racing both on the track and the road, it offers teams/riders the opportunity to push their CdA to the lowest possible figure in real-time whilst maintaining power and comfort. This would mean riders in breakaways could ensure they’re in an optimal position to gain time on the bunch, sprint trains to ensure they’re being as efficient and protective of their leader as possible, and finally give GC contenders the edge when racing from select groups at the pointy end of races.’

George Gray


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