What if you could have a wind tunnel on your bike? With its new real-time aerodynamic drag measurement system, Body Rocket is promising just that.
A number of brands have promised to bring these capabilities to cycling in recent years, but so far, none have gone mainstream. This time, though, it could be different.
Body Rocket has been working on its system for a number of years, but when the brand finally offered us the chance of a test ride, our interest was piqued.
To find out whether we might all be riding around with drag sensors on our bikes in the near future, I headed to Palmer Park Velodrome, in Reading.
Most importantly, I found that Body Rocket’s system worked. The brand also had an unexpected trick up its sleeve in the form of an AI-powered assistant app.
The question remains, though – what do Body Rocket and other aero sensor manufacturers need to do for their technology to finally go mainstream?
What is Body Rocket?
Body Rocket is a live aerodynamic drag measurement system designed for use on road and triathlon bikes.
Most existing aero sensors – such as the Notio Konect or aptly named Aerosensor – rely upon measuring wind data via probes typically positioned on the front of your bike.
By combining this with power and tyre rolling resistance data, these systems can attempt to calculate a rider’s coefficient of aerodynamic drag (CdA).
In contrast, Body Rocket’s system takes direct force measurements at the places where the rider contacts the bike – namely, the saddle, the handlebar and the pedals.
The sensors are akin to the scales a rider and their bike are placed on in a wind tunnel (despite most pictures of wind tunnels focusing on the wind and turbine, the device taking measurements is the scale).
This, Body Rocket says, is what makes its system unique.
Because it directly measures the resistive force of the air acting on the rider as they pedal through it, it doesn’t need to rely on assumptions about things such as rolling resistance.
Body Rocket’s sensors can also measure how the rider interacts with their bike, giving insight as to whether a rider can sustain a given riding position effectively or is, for example, moving excessively on the saddle or pulling on the handlebar.
Likewise, Body Rocket’s system requires input from a power meter to calculate CdA – the brand says it built its own dual-sided pedal-based system because none of the existing options on the market were deemed accurate enough.
All of this data is then transmitted to a Garmin Edge bike computer, via the ConnectIQ app, where you can view live CdA data as you ride and record it for post-ride analysis.
BRIAiN
Bike sensors aside, Body Rocket has another trick up its sleeve in the form of an app it says is driven by artificial intelligence (AI).
The Body Rocket Individualised Artificial Intelligence Network – or BRIAiN for short – is a browser-based application that utilises AI and machine learning to help riders with Body Rocket sensors to conduct and analyse the results of aero testing.
The brand’s reasoning is it’s not much use having the sensors if you don’t know what to do with them, or how to interpret the data.
This is, it must be said, a great point.
Previous devices, such as the Notio Konect or Aerosensor, have typically offered riders little direction in terms of how to use them (beyond the basics of getting them set up and on your bike).
In the hands of aerodynamics experts, this might not be an issue, but for general riders it can make the learning curve steep.
In contrast, Body Rocket says BRIAiN can suggest a testing protocol and things to test, such as positional changes or a change of helmet or skinsuit.
Post-test runs, BRIAiN can then analyse the data captured, determine whether you rode with enough consistency to be confident in the results and suggest further testing and changes to keep refining things.
Testing the Body Rocket system
That’s a lot of information to take in, but arriving in Reading I had one key question – does it work?
Because the system is still in prototype form, I rode a BMC Timemachine One time trial bike, which had everything pre-installed on it by Body Rocket.
As we’ll discuss later, the potential complexity of installing and setting up the various system parts on a bike may be a significant hurdle for the brand, but for now, let’s focus on how it works once all set up (spoiler – it was impressive).
After some initial conversations with Eric Degolier, Body Rocket’s founder, and Callum Barnes, Body Rocket’s head of AI in aerodynamics, about our goals for the test, Barnes prompted BRIAiN to devise a testing schedule for the day.
Setting a baseline
Almost instantly, BRIAiN suggested a series of things to test, as well as how to do it.
The initial suggestions revolved around making positional tweaks – things such as longer reach, more saddle-to-bar drop and so on.
This shouldn’t come as a surprise, though, given most of the biggest (and cheapest) aerodynamic gains are typically realised through optimisations to a rider’s body position.
After setting a baseline CdA with our ‘stock’ setup – which consisted of the BMC TT bike, team-issue BikeRadar jersey and shorts, and a Kask Protone Icon road helmet – the first change we made was to extend the reach to the aerobars by 30mm.
The logic behind such a change is stretching a rider out can help elongate their upper-body shape and lower drag.
Graeme Obree famously took this to the extreme with the ‘Superman' position he developed in the mid-90s. Before this was banned by the UCI, Chris Boardman used it to set his famous 56.375km Hour Record distance in September 1996 – a mark which was only surpassed by Filippo Ganna in 2022.
Run 1
In practice, my CdA jumped significantly from 0.204 to 0.213. In a race scenario, BRIAiN calculated that would cost me 10.8 watts, or a whopping 49 seconds, over 40km.
At a glance, that might seem like a failure from the system, but it's quite the opposite – having clear evidence a change has made you slower enables you to rule it out and return to the ‘faster’ baseline position with confidence.
Without a tool such as this, it could be easy to assume a more stretched-out position must be faster for everyone simply because it follows received wisdom.
Run 2
Because we were also filming content for our YouTube channel, we opted to change the input protocols from this point to test more visually distinct changes, such as a time-trial helmet and a high-end skinsuit.
BRIAiN was more than happy to oblige and amended the test protocol to suit our desired parameters.
This time, function followed form and the long-tailed Kask Bambino Pro Evo time-trial helmet was significantly faster than the Protone Icon – by 13.2 watts, or 60 seconds, over 40km.
Of course, the trade-off is the Bambino Pro Evo has only a few tiny strips for ventilation holes at the front of the helmet and, as such, is significantly stuffier than the Protone Icon on hot days.
Nevertheless, that's a huge difference in performance, especially because I wasn’t testing at what many would class as ‘race speeds’ – I was riding at only around 35 to 40kph. At higher speeds, the difference would likely have been even larger.
This is because the power required to overcome aerodynamic drag is proportional to the cube of speed, meaning if you double your speed you’ll need four times the power to overcome the extra drag.
As for why we tested at those slower speeds – it’s mostly due to a desire for consistency and good data. Testing at race speeds can be a desirable thing to do in theory, but it’s physically demanding.
If you’re riding so hard you can’t keep your body in the same position at all times, this will introduce a lot of noise into the data, making it much harder to discern any small differences between test runs.
Of course, the best athletes can do both – ride near or at race pace for extended periods and hold consistent power, position, and so on – but, unfortunately, the vast majority of us (myself included) are not said athletes.
Run 3
With the TT helmet data under my belt, I squeezed myself into a NoPinz Flow time-trial skinsuit for the final test run.
Developed in collaboration with UK-based aerodynamics experts, AeroCoach, the Flow suit was used by some of the world’s best time-trial riders until it was recently superseded by a newer design.
As with the TT helmet, the suit was faster than my baseline jersey and bibs by 3.6 watts, or 17 seconds, over 40km.
At face value, this might not seem like much, but it's worth remembering my BikeRadar kit isn't some baggy mess – it’s premium stuff made by Sportful, with a tight, form-hugging fit.
Again, as with the helmet, the gap would likely have increased at higher speeds too, because the Flow suit is designed to perform best at speeds between 40 and 65kph.
As we saw when we tested budget aero upgrades at the Silverstone wind tunnel, though, a skinsuit might not be a great-value investment if you don't ride at the speeds they're designed to perform best at.
Run 4
For the final run, BRIAiN had me perform a 3km race simulation – an all-out effort designed to check the consistency of the changes at a higher speed and effort level.
Having not trained much this year, my stats won’t wow anyone, so I’ll spare you the times and specific details.
More relevantly, though, the run showed another small decrease to my drag, saving me an additional 3.6 watts, or 17 seconds, over 40km.
Whether this was the skinsuit and helmet working more effectively at higher speeds, or because of something I instinctively do when riding hard (such as dropping my head lower, for example), would require further testing to discern, though.
Results and analysis
With all that testing done, BRIAiN crunched the numbers and gave a quick analysis.
It suggested there was increased variability in run 4 (the race-pace run) and suggested re-running that one to see if greater consistency could be achieved.
As noted earlier, this could be because I wasn’t able to hold a consistent position when riding on the limit.
Unsurprisingly, it also recommended returning to the faster, baseline body position. It also suggested retesting the time-trial helmet and skinsuit in the baseline position to ensure the gains weren’t tied to the extended reach position.
From there, it suggested two additional aero helmets to compare to the Kask – the original Giro Aerohead and the HJC Adwatt (two helmets Body Rocket says typically perform well on a wide variety of athletes).
Of course, in theory, you could continue to test various positional and/or equipment changes to your heart’s content – and therein lies the benefit of the system. Once the it's installed on your bike, the only major limiting factors are access to test equipment (e.g. other helmets or skinsuits) and a suitable location to perform test runs.
Will Body Rocket or its competitors ever go mainstream?
So far so good, then, but what about the downsides?
First of all, there’s the price, which – at £2,950 – is significantly higher than competitors such as the Notio Konect ($599) or Aerosensor (£779).
Of course, it’s worth remembering this includes a set of Body Rocket’s own dual-sided power meter pedals – which it claims will be the most accurate available – and that both the Notio and Aerosensor require input from a power meter to calculate drag.
If you don’t already have one, you’d therefore need to factor one into the cost of those devices.
Likewise, it could be argued to represent relatively good value compared to buying a new bike, or even a set of high-end wheels, if you measure value in terms of potential performance gains.
Even so, it’s fair to say the Body Rocket system is very expensive and this will doubtless be a stumbling block for many riders.
On the other hand, if you’re the kind of rider – or team – that spends large amounts of money on time in wind tunnels, or with experts at velodromes, it might be easy to rationalise this cost.
As with power meters, Body Rocket says it hopes the price and accessibility of this technology will come down over time, in order to make it more accessible to a wider range of riders.
Compatibility
Cost aside, though, because Body Rocket’s system measures the force of the air on the rider, the data captured measures the rider’s drag in isolation from their bike.
It therefore can’t directly measure changes made to your bike. Like other sensors, though, it can infer these based on assumptions of things such as drivetrain and rolling resistance.
Likewise, because the system is made up of four rather than two sensors, making it universally compatible with today’s bikes (which increasingly use integrated and/or proprietary parts) is tricky, if not impossible.
For its part, Body Rocket says it aims to make its system compatible with “up to 80 per cent of [triathlon] bikes ridden at the Ironman world championships”.
Modern time trial and triathlon bikes are easier to target because, with many bikes coming with armrest risers (which enable riders to adjust stack height), there's typically a natural space for the handlebar sensor to be sandwiched between the armrests and the base bar.
The deep-section seatposts many TT and tri bikes have also offer sufficient real estate for the saddle sensor.
Road bikes are another matter altogether, though.
Body Rocket has a slick-looking prototype built around a Giant Propel Advanced SL 0 belonging to one of its top sponsored athletes, Kristian Blummenfelt.
On this bike, the handlebar sensors are housed within a custom stem, while the saddle sensor perches atop that bike’s aero seatpost.
However, with little consistency between road bike brands, making parts to fit even a small selection of the most popular road bikes available today is no small task.
For example, while the Giant Propel uses a simple D-shaped steerer tube that can accept relatively regular stems, Canyon’s Aeroad and Ultimate road bikes both use proprietary quill stem-style stem handlebars.
Likewise, whereas the reach of triathlon bikes can typically be adjusted independently of stem length (by adjusting the location of the armrests and extensions), with road bikes this is typically done by changing the stem length.
Perhaps additive manufacturing (often referred to as 3D printing) will help Body Rocket solve the conundrum of needing to make custom stems or handlebars to fit every bike and every rider.
Considering the Mythos Elix 3D-printed stem costs £500 alone, though, it seems unlikely this would be a cost-effective solution unless cheaper materials can be used instead of titanium.
Demand
Perhaps the largest hurdle, though, could be convincing riders they want one.
Many riders now buy into aerodynamics as a concept, and are willing to shell out for bolt-on upgrades such as aerodynamic carbon wheels, aero helmets, narrow handlebars and so on.
Relatively few people will have ever been inside a wind tunnel, or had an aero testing session at a track, though, and many simply want to ride their bikes in their free time rather than performing dedicated ‘testing’.
Just like when power meters first launched, then, persuading riders to part with cold, hard cash for a device that spits out data they’re unfamiliar with might be tricky.
Bikes of the future
When power meters first appeared on the scene back in 1987, it was something you needed to bolt on to your bike after the fact, with wires galore.
Fast forward to 2024, though, and many bikes now come with wireless power meters fully integrated into their builds.
Despite these potential hurdles, then, could we see a future where the Body Rocket system or other aero sensors are integrated into bikes at the point of fabrication?
I believe so. Of course, that would require deals with bike and/or component manufacturers to make this feasible, but if demand for such devices can be proven then it’s not difficult to imagine.
