The stability of the bicycle

Abstract

Almost everyone can ride a bicycle, yet apparently no one knows how they do it. I believe that the apparent simplicity and ease of the trick conceals much unrecognized subtlety, and I have spent some time and effort trying to discover the reasons for the bicycle's stability. Published theory on the topic is sketchy and presented mainly without experimental verification. In my investigations I hoped to identify the stabilizing features of normal bicycles by constructing abnormal ones lacking selected features (see figure 1). The failure of early unridable bicycles led me to a careful consideration of steering geometry, from which-with the aid of computer calculations-I designed and constructed an inherently unstable bicycle.

Bicycle dynamics and control: adapted bicycles for education and research

“…It can nevertheless be shown that these weak effects contribute their share to the stability of the system. [68] Jones [13] experimentally determined that gyroscopic action plays a relatively minor role in the riding of a bicycle at normal speeds. Jones wanted to design an unridable bicycle, and he investigated the effects of gyroscopic action experimentally by mounting a second wheel on the front fork to cancel or augment the angular momentum of the front wheel.…”

“…Its "feel" was a bit strange, a fact I attribute to the increased moment of inertia about the front forks, but it did not tax my (average) riding skill even at low speed. [13] Klein and students at the University of Illinois at Urbana-Champaign (UIUC) conducted a number of precession canceling and altering experiments in the 1980s based on two experimental bicycles that are similar except for the front fork geometries. The bicycle in Figure 11 has an unaltered steering head and a positive trail.…”

Genetic Algorithms for a Single-Track Vehicle Autonomous Pilot

“…The closest model to our purposes is [7] which considers a bicycle as a nonlinear, nonholonomic, non-minimum phase system. The stability and control of a bicycle are also of interest [11], [8], as well as the study of its aerodynamics [5].…”

Human-Powered Vehicles - Aerodynamics of Cycling

“…It seems clear that the gyroscopic contribution is not the main assistance to guarantee the stability of a bicycle, but however the problem is not completely solved yet [Jones, 1970;Cleary et al, 2011;Kooijman et al, 2011].…”