Tests show that standard cone bearings have less friction than sealed ball bearings Traditional cup and cone bearings were compared with cartridge bearings with and without seals. Two types of lubricant were also compared. For each bearing configuration, measurements of the frictional drag torque were made for different types of bearings with loads varying between […]
Study shows how slow most bikes really are
Resistance parameters measured for real cyclists intercepted in Vancouver For the first time, scientists have reliably measured how efficient typical urban bikes actually are. Their study showed that most people’s bikes are much slower than previously thought. There is also more variation between different bikes. Two things primarily determine how fast a bike is when […]
Full-scale bicycle aerodynamic evaluation methodology developed
A full-scall wind tunnel test method has been created at RMIT University. The bicycle is mounted on a platform which is itself mounted on a load cell. The load cell has 6 degrees of freedom (DoF) allowing drag, lift and side forces to be measured. The bicycle can be orientated at different yaw angles to the […]
Model for Speed and Power in Track Cycling
Sophisticated model including slip and steering angles shows accuracy within 0.2 percent This study sought to improve on the accuracy of existing models for the speed of a track cyclist. It was based on the governing equation: where η is the transmission efficiency, Pin is the power delivered by the cyclist, dt is a discrete […]
Calculating Hub Gear Efficiency
Simplified method to calculate epicyclic transmission efficieny early in design Standard methods for analyzing transmission efficiencies assume that all of the power flows through each gear in a sequence. In a hub gear, the planetary gear trains (PGTs) or epicyclic gear trains involve a number of planet gears transferring power in parallel. This requires special […]
Simulation of drag and heat transfer by cyclist body part
Many elite cyclists use wind tunnels to improve their aerodynamic performance. The wind tunnel gives information on the total drag in different positions. They can, therefore, try different positions to see which gives the lowest drag. This is something of a trial and error process. In this study Computational Fluid Dynamics (CFD) is used to […]
Experiments Prove Equation for Bicycle Power
Validation of a Mathematical Model for Road Cycling Power This important study was carried out to test whether existing mathematical models can accurately predict power during road cycling. It showed that the model can predict power with an accuracy of about 3 percent (standard error of 1.6 percent) A number of resistance forces cause power […]