"the noise of the motors"

The tandem bicycles with gasoline engines that were used to 'pace' the bicycle races of the 1920s were designed by Oscar Hedstrom. Although they largely failed in their intended function of sheltering the riders from the wind, the bikes themselves soon earned a favourable reputation for their reliability. Hedstrom was co-founder of the Indian Motorcycle Company, building the firm's first prototype in 1901. 

Carl Oscar Hedström with the first prototype of Indian
Public DomainCarl Oscar Hedström with the first prototype of Indian - Credit: Gede