Dynamic tire properties, specifically the forces and moments generated under different circumstances, have been found to be important to motorcycle dynamics. A similar situation may be expected to exist for bicycles, but limited bicycle tire data and a lack of the tools necessary to measure it may contribute to its absence in bicycle dynamics analyses. This paper describes tools developed to measure these bicycle tire properties and presents some of the findings. Cornering stiffness, also known as sideslip and lateral slip stiffness, of either the front or rear tires, has been found to influence both the weave and wobble modes of motorcycles. Measuring this property requires holding the tire at a fixed orientation, camber and steer angles, with respect to the pavement and its direction of travel, and then measuring the lateral force generated as the tire rolls forward. Large, sophisticated, and expensive devices exist for measuring this characteristic of automobile tires. One device is known to exist for motorcycle tires, and it has been used at least once on bicycle tires, but the minimum load it can apply is approximately 200 pounds, nearly double the actual load carried by most bicycle tires. This paper presents a device assembled for less than US$1000 that measures bicycle tire cornering stiffness. It consists of a small cart designed to take advantage of any sufficiently long, level, rigid, and smooth stretch of floor adjacent to a plumb, straight, rigid, and smooth wall to provide the test track. Several purpose-built tracks, however, are also described. A flat and straight track avoids issues created by either vertical or horizontal curvature. The apparatus uses an instrumentation system from Pasco intended for classroom experiments: two force sensors to measure lateral force, and one force sensor to measure torque, and a rotary motion sensor to measure distance travelled. (Author/publisher) For this paper, other papers and posters presented at this Symposium see http://bicycle.tudelft.nl/bmd2010/
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