Unveiling the 'wind voice' of carbon fiber wheel sets

When selecting carbon bike wheels, people are often attracted by the striking "whooshing" sound of carbon fiber bike wheels (not referring to the sound of percussion instruments). Some people may find the sound a bit noisy, but when you accelerate and start, the sound emitted by the carbon wheelset will add a sense of luxury to your bike, while also bringing stronger power, especially on some  bike wheelsets that use carbon fiber material enclosed design, this effect is even more significant.

So why is the sound of carbon fiber bike wheels always so eye-catching? And some other bike wheel sets are relatively quiet? Although this question may seem simple, upon careful consideration, you will discover that there are complex principles hidden within it.
Strictly speaking, this sound is actually generated by "turbulent noise", which is a resonance effect. So what is the correlation between this sound and the height of the wheel profile, carbon fiber material, and internal structure of the carbon bike wheel set?

The answer is actually quite simple. Firstly, that noisy sound is caused by resonance, but it is greatly influenced by manufacturing processes, materials, and internal structures
Simply speaking, resonance refers to the phenomenon where an object experiences an increase in amplitude at a specific frequency and wavelength.

Overall, the larger the surface area of the wheelset, the louder the sound produced. This also explains why the "whooshing" sound of fully enclosed wheelsets is the loudest, followed by high-end wheelsets. Bola believes that once the height of the wheel profile is below 40 millimeters, there is not enough sidewall area to push enough air, so the amplitude and sound effects are very low
In addition to surface area, the internal and external structure of the carbon  wheelset also plays an important role, especially the tension on the side walls or fully enclosed surface of the bike wheelset.

A fully enclosed carbon bike wheel set without spokes inside, its surface is like a large resonance surface with low natural frequency, easily excited by ground vibrations, like a drum, moving air inside and outside to create sound
Compared with the old Bola fully enclosed wheel, the above wheel set usually has a thin layer of foam core behind the carbon fiber enclosed surface, which plays a damping role to suppress vibration.

The use of carbon fiber materials can also affect the sound of the wheelset. Bola explained that high-end wheels typically use thinner and more layered carbon cloth stacks, as well as a higher proportion of carbon fiber and resin, resulting in lighter, thinner, and more resonant rim sidewalls.

The disc brake  carbon bike wheel set may be able to reduce noise to a certain extent. With the popularity of disc brake systems, manufacturers can use rubber or low-temperature resins that can enhance elasticity to manufacture wheel sets, thereby increasing the damping coefficient of the resin itself and reducing noise.
Overall, the noise of the wheelset may reflect its quality, price, or market position, but with the development of technology and changes in materials, Bola high-end wheelsets can also become quieter.