46. TIME SAVED WHEN DRAFTING BEHIND MOTORBIKES

Image from Blocken et al. 2020. (1)

During crucial moments of road cycling races several motorbikes of race organization and media are around cyclists. As a consequence, there are many arguments about the drafting advantages that they could give to a given rider. The minimum distance set by the UCI between a moto and the riders behind is 10 meters. However, even drafting at a bigger distance could create some benefit.

How much drafting behind a motorbike at different distances is beneficial for a cyclists?

A study published by Prof. Bert Blocken and Colleagues (Eindhoven University of Technology, Netherland) on Sports Engineering in 2020 tried to answer this question. (1)

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WHAT DID THEY DO?

• Wind tunnel simulations were performed using models representing a cyclist and a motorbike carrying two person.

Picture of the wind tunnel simulations. Image adapted from Blocken et al. 2020. (1)

• The engineers calculated the aerodynamic drag decrease at 54 km/h between no motorbike vs having a motorbike on the front at different distances (d in the figure below). This speed (54 km/h) can represent the speed in time trials or final crucial phases of road races. Basing on the aerodynamic drag decrease, the drafting advantages were also calculated in terms of seconds per kilometer.

Image from Blocken et al. 2020. (1)

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WHAT DID THEY FIND?