The secret to our success
At Knight Composites, we do things differently. You could even say we do things a bit backward. The majority of aero wheels place the design focus on the tire and rim’s outer edge. The Knight design looks at the problem from another angle – the wheel’s trailing edge.
Why do we do this? It’s simple. As the wheel is part of a dynamic system, we look at the wheel, bicycle and rider, as a whole rather than in isolation. After extensive modeling and testing, our engineering team determined the most effective aero impact can be made by focussing on airflow as it moves away from the wheel across the bicycle and rider. The resulting design concept of Trailing Edge Aerodynamic Manipulation (T.E.A.M.) creates a faster, more predictable ride.
During development we look at the cross-sections of the wheel’s shape (air-foil). And we look at the wheel itself to see how the air moves at a wide range of side angles (“yaw”). We examine how and where the airflow separates from the wheel’s surface. Finally we look at where this separation creates turbulence. It is at this point, as wheel designers, we can have the most impact.
On the front half of the wheel, the tire really messes things up despite an engineers’ best efforts. What it comes down to is that the round shape of a tire just isn’t a good airfoil. When the air hits the tire, it’s going to separate, so you see more turbulence coming off the the front part of the wheel than on the rear. To reduce drag from airflow separation, T.E.A.M. design focuses on the air as it moves away from the wheel.
The other half of any aero wheel’s story is its stability in a cross wind. With almost any wheel, the air on the side facing the wind is going to remain attached. The trick is keeping the air attached on the other side of the rim, that’s where stability comes in. Compared to many other aero rims, T.E.A.M. design has more of a gentle progression of shape from the front of the rim all the way to the tire. Because of that, the wheel wants to turn into the wind, which helps keep you riding in a straight line.
As you can see from the image above, by managing the airflow from the trailing edge, and keeping it attached to the rim as long as possible, we can put more lift behind the wheel. This creates a gradual widening of the airflow as it passes over the rider and bike. The real word result is a stable wheel that reduces drag, creates lift, and gives you more usable watts. This is what makes our design so fast.
A lot of companies try to create symmetrical airfoils, making the leading edge the same as the rear. That makes the leading and trailing edge of the rims rather blunt. We put heavier emphasis on how the air hits the back half of the rim. When the down tube is behind the tire, the rim/tire/frame acts as one giant airfoil.
T.E.A.M. design ensures that when the air leaves the trailing edge of the front wheel that it doesn’t mess up the air hitting the frame. The result is a proprietary wheel shape that:
- Creates a 30g reduction in drag at 15° yaw
- Reduces wind steer by shifting a higher % of lift to the rear of the wheel = more stable descending and precise cornering
- Eliminates flaws in more common “V” and “U” shapes
- Gradually widens airflow around the trailing edge = less disturbance over the downtube and frame
Wanna know more? Here’s Knight design engineer, Kevin Quan, with a little bit about our shape and wind tunnel testing.