When the caster moves or has to control its direction, the force must be passed through the object to the casters and overcome some resistance, the resistance depends on the size: weight, wheel diameter, wheel material, tread shape, casters rotation of the situation Wait. For the rolling resistance test, the standard is to install three casters on a fixed three-arm base, according to different test levels, the 300/600 / 900N test load (including the quality of the base) applied to the base, A horizontal traction allows the caster speed on the test platform to be 50mm / s (± 5% of allowable deviation) and 10S. As the caster rolling began with a large friction and an acceleration, the test after 5S to measure the level of traction, the size of the test load does not exceed 15% of qualified. The rotation resistance test is to install one or more casters on a linear or circular motion tester so that the direction is 90 ° to the direction of travel. A test load of 100/200 / 300N is applied to each casters according to different test levels. Apply a horizontal traction force so that the test bench on the caster speed of 50mm / s (tolerance ± 5%), and in 2S rotation occurs. Record the maximum horizontal traction of the caster, which does not exceed 20% of the test load.