Even today there are no data on typical operational loads placed on bicycles despite the fact that the number of bicycles manufactured and used globally is far higher than that for cars. The aim of the present investigation was to determine operational loads (loads caused during customer use) for bicycles which could be used as reference values at the design or test stage to ensure that the bicycle is structurally durable. The call made for bicycles to be structurally durable resulted from the fact that bicycle loads vary greatly according to the individual rider and that the ability of components to tolerate strain is subject to statistical variance. Using 13 adult, 2 juvenile and 2 children's bicycles, al] of which were equipped in accordance with the Motor Vehicle Construction and Use Regulations and consequently permitted to be used in road traffic, the loads acting on the bicycles were recorded when they were ridden on cycle paths, roads and bumpy tracks. The data were supplemented by recording special occurrences such as emergency braking manoeuvres, minor fails, collisions with walls, quick accelerations with the rider standing up in the pedals, small jumps and also abuse by means of overloading and riding over pot-holes, kerbs and steps. Eighty measuring runs were carried out with the 17 bicycles; the overall testing period amounted to more than 14 hours; a total of approximately 175 kilometres were travelled. Forty-one riders were involved in the tests. After certain bicycle areas susceptible to failure had been selected, the following variables were recorded, taking into account the velocity of travel and the type of surface being travelled on: (i) horizontal and vertical handlebar forces; (ii) torque in the front of the frame (caused by reciprocal loads on the handlebar); (iii) normal force and flexural torque on the saddle pillar at right angles to the plane of the bicycle frame; (iv) horizontal and vertical loads on the front wheel axle; and (v) pedal force on the tread crank. This investigation probably constitutes the most comprehensive data recorded to-date on the loading of bicycles in use. The original report contains appendices with detailed representations of the data recorded. These appendices were omitted in the present publication. They can be consulted at BAST.
Abstract