Argon 18 Nitrogen Pro Red AXS
In stock at 1 shop in New York City
Prices and stock checked Oct 22.
Where to buy
1 shopAbout this bike
The Argon 18 Nitrogen Pro Red AXS Bike was built around a single question that most aero road bikes never honestly answer: how do you make a rider faster, not just a frame? Argon 18's answer was to model the complete system — bike and rider together — rather than optimizing the bare frame in isolation, and the result is a claimed 24 watts of savings at 45km/h compared to the Sum Pro it replaces. At 6.95kg claimed in size medium with a power meter, integrated bottle cages, and a computer mount already included in that figure, the Nitrogen Pro arrives as a complete race bike with nowhere to hide and nothing left to add.
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The frame is full high-modulus carbon built to Argon 18's Pro-level layup, the result of evaluating 130 different tube profiles before settling on the final shapes. Bottom bracket stiffness is up 23% compared to the Sum Pro, head tube stiffness is up 6%, and the overall chassis is 18.5% stiffer — all while maintaining equal vertical compliance. That last detail is what separates a bike that's fast from one you actually want to ride for four hours. The seat stays run horizontal and dropped, borrowing geometry from Argon 18's track bike program to reduce drag at the rear of the frame. A T47 threaded bottom bracket shell — fitted here with a CeramicSpeed SLT DUB bearing — keeps the drivetrain foundation efficient and serviceable. Fully internal cable routing handles the rest of the aerodynamics quietly.
The fork is the product of 25 separate prototypes and is 80% stiffer than the previous Nitrogen disc fork. The front brake caliper is tucked behind the fork legs with only the cable exposed, and the fork crown is recessed to blend with the flow-optimized head tube as one aerodynamic system rather than two separate pieces. The cockpit is Atten's CHB-01 — an integrated one-piece aero bar and stem with an arrow-shaped cross-section, a 3° inward flare on the drops for ergonomic hand positioning, and a geometry that delivers 15mm more stack and 5mm less reach…
