This article was produced in collaboration with Argon 18 and was first published in Issue 139 of our magazine
From the frame to bottle cage bolts, each component on a modern aero bike can impact air resistance. But they don’t do so in isolation. Each contributes to the whole system, and interacts with the surrounding components to minimise or magnify how much speed-sapping drag is left in their wake.
Traditionally, bike manufacturers have had limited control over this relationship. When approaching the design of an aerodynamically optimised bike, most will pour their research and development hours into refining the backbone of any build – the frame and forks – and a range of other components built by a different company will be specced to fit the brief.
Argon 18 isn’t like most manufacturers, though. When faced with the challenge of developing the best modern road race bike and its fastest bike ever, the Canadian-founded company tore up the rulebook, and set about creating something that was optimised as a complete system.
This meant it wouldn’t restrict itself to the confines of componentry currently available on the market; if there wasn’t already a solution that fit its goals, it would craft its own under the Atten (Danish for ‘18’) label.
“The way this industry is structured is everybody does their own thing and you try to put it together and see if it fits,” says Alexander Côte, Argon 18’s product manager. “For us it’s unacceptable going forward. This approach is something we won’t be doing if we can do better.”
The result is the Nitrogen Pro. Almost three years in the making and decked out with proprietary wheels, handlebars and bottle cages in addition to some of the best groupsets and finishing kit money can buy, it achieves its ambition by being 24 watts faster than Argon 18’s previously fastest frameset, the SUM Pro. It also weighs 6.95kg in a complete, rideable build with SRAM’s Red AXS power meter groupset, two bottle cages, and a computer mount in a size medium.
But it’s much more than another aero bike. It’s a revolutionary way of approaching bike design, where every stage of air resistance’s path is analysed and optimised – from its first contact point at the tyre to the numerous drag-creating surfaces it passes en route. And Argon 18 is just getting started.
Pioneering philosophy
Looking beyond the norm has always been part of the brand’s DNA. Founded by the former Canadian professional rider Gervais Rioux in 1989 in Montreal, his ambition was to use his years of training and racing experience to create a goldilocks bike that combined race-winning performance with a comfortable fit and ride feel.
In 2001, after 12 years of producing alloy frames, the company launched its first carbon fibre design, joining the race to use the revolutionary material as it had started to proliferate the mainstream.
Four years later, its first monocoque carbon frame – Gallium – was released, while it started making waves in triathlon, where its bikes were piloted to numerous World Championships.
Its lead sponsorship of the Bora-Argon 18 team for the 2015 and 2016 seasons saw the manufacturer make its Tour de France debut, while its presence at the pinnacle of road cycling continued with Astana between 2017 and 2019, picking up wins at Liège-Bastogne-Liège, 11 Grand Tour stages and podium finishes at the Giro d’Italia and Vuelta a España.
Its success wasn’t limited to the road, and in the velodrome – often regarded as cycling’s Formula One – it was responsible for numerous Olympic medals, including gold for Kelsey Mitchell in the women’s sprint and Denmark in the men’s madison at Tokyo 2020.
Considering its size and stature, with a 15-strong R&D and product department and a total headcount of 70 across its Montreal and Copenhagen offices (which includes everyone from mechanics to accounts), Argon 18 punches above its weight on the professional stage.
But WorldTour wins and Olympic medals aren’t its sole driving force. Its absence from the WorldTour since 2020 is a conscious decision, and instead of pouring money and time into the sponsorship and development of bikes for pro teams, it’s able to focus on premium carbon fibre bikes for the mass market. The scale of the operation also means that each bike is assembled in-house in Montreal or Copenhagen, and every potential customer can have a conversation with an Argon 18 employee – giving the brand a personality lacking from larger, volume-focused competitors.
Its agile size is also how it can embark on projects like the Nitrogen Pro, where it has the flexibility, time and R&D expertise to get philosophical about decisions as granular as thru axles – shaving 18g off of each, while retaining the structural integrity needed – without external pressures. And the outcome is a thing of beauty.
Real-world speed
To make its fastest-ever bike, going aero was imperative. “Aero is key in racing, even at the speed that amateurs race,” says Côte. “When you ride over 20km/h, aerodynamics takes over as the main contributor to resistance. Also, when you analyse UCI sanctioned races, you realise that less than five percent have more than 1,000 metres per 100 kilometres and end on a hill. People are riding on flat or rolling terrain, and even if they need to climb over a mountain top, they’re limited to a 6.8kg bike.”
While minimising air resistance was important, Argon 18 didn’t want something that performed well in a wind tunnel but was unrideable on the open road. “Although aerodynamics were the core project, we still needed to consider aspects of system weight and the characteristics of fit, and the interaction of all components together – not just from an aero perspective, but stiffness, comfort and ride feel, because it’s all part of that race-winning moment.”
It’s why when conducting CFD and wind tunnel testing during development, it measured using a rider and wind-averaged drag – the average of the yaw angles you would encounter in the real world – at speeds of 45km/h, rather than a too-slow 40km/h or unobtainable 55km/h.
Front to back thinking
When starting the bike’s design with the first contact point – the tyre – it chose a 30C tyre, and specifically the Vittoria Corsa Pro.
“It’s what the pros and amateurs ride on out there, so why make something in the lab, in isolation, when the reality is different? This is where most of the brands get it wrong at the moment – optimising for a test rather than real-world application. The Corsa Pro was the most well rounded – puncture resistance, grip control, and aerodynamic performance.” The issue was, it measured 31.4mm when fitted, and set in motion a chain of events that would lead to the bike’s first proprietary component.
In its pursuit of crafting the complete system, Argon 18 turned to the Dutch wheel manufacturer Scope – creator of the Artech 6.A, which is regarded as the world’s most aerodynamic wheel. The only issue was that the fish scale-inspired rim had been optimised for a tyre measuring 30mm. “It’s a lot of effort for 1.4mm, but it becomes a proprietary rim shape, which is wider and shaped differently than the stock product,” says Côte.
The resulting Atten x Scope Artech 6.A+ wheelset is only available for the Nitrogen Pro, and features 3D printed scandium alloy hubs that are half the weight of a CNC’d design, 65mm rims, 1,320g weight and a €4,000 price tag.
Like other aspects of the bike though, real-world application was at the forefront of the design process. “The rims are a hooked design. Hookless isn’t worth the slight weight reduction. The safety, rideability and usability of the product comes ahead of 25g, especially when a 65mm comes in at 1320g.”
Hitting the sweet spot
Wheels sorted, it was time to turn attention to the frame and fork. More than 130 tube profiles and 25 fork leg designs were tested through more than 1,000 hours of CFD and three, multi-day wind tunnel sessions. Multi-directional development was key. “It’s like chicken and egg,” says Côte. “How does this new thing affect the first thing you did?”
The solution was the sweet spot of aero influence and carbon layup that ticked the boxes of aerodynamics, weight, fit and handling. It has an increased stack of 15mm compared to the SUM Pro to create a more progressive fit, while the BB is lowered by 2mm to factor in the increased height of larger volume tyres. It has an extended ‘flow-optimised’ headtube, but retains width rather than chasing extreme marginal aero gains to aid assembly, usability and durability.
The frame’s lower half, from its track- and triathlon-inspired ‘speed bridge’ seat stays down, is focused on power transfer and handling, and is 18.5% stiffer than the SUM Pro. The upper half, meanwhile, is responsible for its lightness and compliance. “The further up you go from your pivot point – the BB and thru axle – the more you feel the weight when sprinting or out of the saddle. For ride quality, we therefore try to keep everything that is higher than the middle of the bike as light as possible, including the frame’s lay up.” This influenced the proprietary D-shaped, 160g seat post, but the final user was also at the forefront, as the full carbon and padded 119g Repente Quaser CR saddle that tops it, proves. “We could put a 80g saddle on it and claim 40g on that complete build,” adds Côte. “But is it rideable for everyone? Not necessarily. Is it fully padded? No. We went for the most ride optimised saddle.”
Finishing touches
In its pursuit of perfection, Argon 18’s attention to detail knew no bounds. It couldn’t find the optimum handlebars and unlike the wheelset, no manufacturers were willing to collaborate, so it set about crafting its own – the CHB-1 Aero Cockpit. It claims a 3.2 watt saving compared to the popular Vision Metro 5D ACR Evo, but its design is focused on ergonomics and ride comfort as much as its arrow-shaped aero finish – a 3° inward flare at the hoods avoiding the need to turn shifters in and twisting hydraulic cables in the process. It’s thin and light too – weighing 320g – and only compatible with wireless groupsets as a result.
Argon 18 also optimised the bike to be ridden with bottle cages – “people ride with a bottle cage, they need to carry water” – and it’s faster with regular bidons than leaving them empty. But both have a different design, with an empty seat tube-mounted cage impacting downstream differently to the one fixed on the downtube. To minimise its drag when not carrying a bottle, it’s vented to enable airflow to pass through en route to the rear wheel.
This in itself is a microcosm of the fine level of details that Argon 18 was willing to explore when developing the Nitrogen Pro, setting new standards for what’s possible when you look at the system as a whole rather than what a manufacturer has traditionally been able to influence. Combined with a focus on real-world conditions rather than success within the confines of a lab, and the Nitrogen Pro is not only Argon 18’s fastest-ever bike, but might just achieve its second goal – to be the best modern road race bike.
Read more from Rouleur Issue 139:
