20 In Bicycle Front and Rear Wheel set. 20 X 2.125 STEEL FRONT WHEEL 36 SPOKE 12G UCP 3/8 AXLE SINGLE WALL CHROME. 20 X 2.125 STEEL FREEWHEEL 36 SPOKE 12G UCP 3/8 AXLE SINGLE WALL CHROME. Hub: 1/Speed Free Wheel 3/8 Axle.