Stepped-Pulley-&-Axle-Rapid-PH10400-p-This-13cm-diameter-moulded-wheel-has-4-grooves-of-different-diameters-in-the-ratios-1-3-5-amp-7-It-is-ideal-for-demonstrating-how-a-change-in-diameter-changes-the-performance-of-a-system-e-g-torque-&-speed-p-Rapid-Wheel-Axle-130mm-Diameter