Cycling shoe stiffness is an important factor when it comes to performance. Stiffer cycling shoes allow for more efficient power transfer from the feet to the pedals, resulting in a more efficient and powerful pedal stroke. Stiffer shoes also offer better support and stability, helping to reduce fatigue and improve rider comfort. Additionally, stiffer shoes are usually lighter and provide better aerodynamics, which can give cyclists an edge on the road. Ultimately, the stiffness of a cycling shoe should be chosen based on the rider's personal preference and riding style.