Osman Isvan is an engineer specializing in electroacoustics and an avid recreational, touring and utility cyclist. He lived in the Boston, Massachusetts, USA area for many years before moving to Nashville, Tennessee and then to California. While in Massachusetts, he was an active member of the Charles River Wheelmen now Wheelers) bicycle club, and he still has many friends here. His articles here describe a noted bicycle tour, the Tour of New England, which touched on six states in three days, as well as theory and experiments on bicycle propulsion.
-- John Allen
The Tour of New England is an iconic bicycle tour which touched on all six New England states over a three-day weekend. Osman describes its origin and history.
This is an introduction to Osman's series of articles on power production, wind and speed.
This article, which appeared in the June, 1984 issue of Bike Tech, examined how the ground speed of a bicycle would change in response to winds at different speeds and from different directions, with the same propulsion power.
The idea of modeling the cyclist as a source of constant power is rooted in the principles of biomechanics and exercise physiology. Electric vehicles, in total contrast, are constrained mainly by the amount of energy contained in a battery...
Development of wind sensors for bicycles would make power meters accessible to more cyclists, and wind-aware cycling computers would spawn new concepts such as crowd-sourced wind maps and more.
Big data as it applies to bike rides; the value of statistical analysis: Osman analyzes data from over 1000 of his own bicycle rides to see what they show, and describes what might be discovered by mining the huge troves of data held by Strava, RidewithGPS and other GPS-based mapping services. Osman makes a particularly trenchant suggestion for e-bike design based on his analysis, and discusses issues of data privacy.
Osman takes another deeper look into hills and winds.
The mechanical structure of a person riding a bicycle is represented by a dynamic lumped-element model characterized by its natural frequencies and mode shapes. Static loads are superimposed with dynamic loads with random excitations due to ground reaction forces when the bicycle is ridden on an uneven road surface. The structure reacts to these inputs according to its “frequency response”, which typically serves as a low-pass filter that isolates the rider from road vibrations. The effective suspension compliance arises from the elastic properties of structural components such as tires, fork blades, “frame flex”, muscles and tendons. To demonstrate the viability of dynamic modeling with lumped elements, Osman uses a simplified model with only three degrees of freedom and simulates system response under steady-state and transient conditions. He investigates the effects on vibration isolation of several key parameters including tire pressure, frame compliance and riding position.
Last Updated: by John Allen