Designing an aerodynamic bicycle is maddeningly difficult. Compared to a plane or a car, there are a stunning number of surfaces and edges to evaluate. Worse, with each pedal stroke a rider fundamentally changes the aerodynamics of the system. Consider that planes don’t have to flap their wings. When we design, we consider the entire system—bicycle, rider and wheels. That means looking at a number of rider positions as well as evaluating different tyres on our wheels.
The only way to deliberately design a bike immune to the wind is to use Computational Fluid Dynamics software (known as CFD). Many bike companies outsource this work to engineering firms. We do all our modeling in-house on powerful workstations that make a home computer look like a pocket calculator.
To achieve superior performance we devised our OTIS—One Total Integration System. OTIS includes a one-piece bar and stem for smoother airflow, a proprietary external steerer fork that decreases frontal area whilst giving the wind more surface to follow and our Twin Vane split down tube.
The Twin Vane down tube may look like an unusual response to aerodynamics, but in fact it is our best answer to the problem of creating an aerodynamic road frame that has the stiffness and feel of a traditional road bike. When paired with our Black Inc 50 wheels, the two work together to channel wind through the downtube in a smooth flow before the seat tube splits the flow and sends it past the rear wheel.
While most aerodynamic wheels work best with 23mm tyres, we have engineered the O2 and One Chassis and Black Inc wheels so their sweet spot is with tyres between 25 and 28mm wide to take advantage of the lower rolling resistance and improved traction and ride comfort offered by the new generation of tyres.
We pay attention to aerodynamics on our O2 as well. Even though it is meant to be a fairly traditional road bike, we considered how it functions in the wind. That’s why we equipped it with our Black Inc 30 wheels. You’ll also see that there are no hard edges in the frame and the fork and that each of the tubes flow into each other with smooth transitions. Hard edges can create pockets of turbulence that function like tiny parachutes.
With our Slick triathlon and time trial bike, we left no trick untapped. We designed a specially optimized version of our Twin Vane down tube for the Slick to take advantage of the lessons we learned with the One. Likewise, the Slick uses our wind-piercing external steerer fork. We also designed the frame and fork to be paired with our Black Inc Three front wheel and Disc rear wheel for the ultimate in slippery speed.
For us, aerodynamics are a fundamental part of our work, not an afterthought.