Taking queues from the success of its Nitrogen Pro aero bike and its Gallium Pro lightweight climber, Argon18 has unveiled a new road model called the Sum, which balances weight and aerodynamics into one design. And, the Canadian brand has the white paper to prove it.
According to Argon18, based on computational fluid dynamics, the new Sum cheats the wind on par with the Nitrogen Pro Disc, while it’s 9% faster than the Gallium Pro Disc. It’s also said to offer a more comfortable ride, achieving a claimed 30% to 35% more in compliance versus its aero bike brethren.
“A simulation of stage 6 of the 2019 Tour de France (which included 3,500 meters of climbing and a summit finish on La Planche des Belle Filles) showed a time savings of 75 seconds for the Sum over the our previous lightweight climbing bike, the Gallium Pro Disc,” boasts Argon18.
The Sum achieves this thanks to a mix of kamm tail aerofoil tube profiles, dropped seatstays, full internal cable routing, a D-shaped seatpost and enough clearance for tires up to 700 x 30c.
Interestingly, Argon18 decided to forgo an integrated cockpit, instead utilizing a more traditional set-up in order to save weight and offer more flexibility with respect to component choices.
However, the Sum does get Argon18’s signature 3D system that allows the upper headset bearing and cockpit to be raised without impacting rigidity, along with FSA’s ACR (Aerodynamic Cable Routing) system for a tidy appearance.
The Sum is offered in two guises, the Sum and the Sum Pro.
Here’s how the models breakdown:
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