Influence of the rider seating position on motorcycle aerodynamic performance

Aerodynamic design is a key aspect in race car development, and is usually based on wind tunnel evaluation and CFD. This is not usually the case in motorcycle design. In recent years, some aerodynamic analyses have been carried out, but wind tunnel experimental evaluation is very seldom used. This paper addresses a specific aspect concerning the rider's position. The goal of the investigation is to provide the rider with information about the most efficient position to reduce aerodynamic resistance. Four different types of motorcycle were considered, and an experimental investigation program was carried out. During each test, real riders on full-scale motorcycles were evaluated. Each rider wore his own race suit while riding the motorcycle and each test was characterized by a specific rider position gauged by the distance between the rider's pelvis and a reference point on the motorcycle saddle. Different rider positions were compared and general trends were found. This paper illustrates the experimental procedures and presents the main results in terms of drag resistance for each test. As a final result, the most efficient rider position is suggested.