Many athletes chase speed with bikes and wheelsets. Notio-led research however confirms what many pros already know: while upgrades are always appealing, bikes have little to do being aero, accounting for only 20 percent of total resistance.
So, where’s the other 80 percent? Weight, gear and bike set-up, say our engineers. Finding speed within these factors requires measurement, and for more and more athletes, that’s being done outside wind tunnels.
Ride up grades, not upgrades
In cycling, triathlon or on the track, rider resistance is determined by air around a rider, altitude gain, acceleration resistance, and rolling and mechanical resistance. If you can measure and find a way to limit resistance in all its forms, you’ll be faster on the bike.
For a rider pushing 300W, with a 0.25m2 Coefficient of Aerodynamic Drag and who weighs 70kg, for example, resistance to movement on a 0% gradient is 90% determined by environment, kit and set-up. That’s a big window with lots of room for optimization. Similarly, on a 5% climb, altitude resistance becomes a greater obstacle in the face of speed: 82% of what needs to be managed to go fast. Not surprisingly, going fast up hills is dramatically affected by measuring and optimizing weight.
“Reality for most athletes is that aerodynamics has much more to do with the rider than the machine,” explains Simon Demers, an engineer with Notio. “The advantage of working with a tool like the Notio is that you measure what it actually means to ride efficiently.”
On flat roads, most of your power is spent fighting air resistance. On hills, altitude gain takes over the fight. In either environment, rolling resistance (and mechanical loss) has an impact, but the effect is low. So, while N+1 (see #12) is always appealing, it’s obvious that when it comes to aerodynamics, it’s less about the bike and more about the person sitting on it.
Notio estimates CdA based on rider measurements and environmental parameters. Analyzing this data allows riders to find efficiencies and greater speed by measuring and optimizing the effect of weight, set-up and efficiency. In most instances, these are variables riders can control and in turn, ones that unearth more speed with the same watts.