How to Install & Repair Rear Bearings on a BMX Bicycle

BMX bikes use a rear hub with bearings contained in races around a central axle. With time, water intrusion and use, the bearings in the hub will wear out and need replacing. This task requires some specialized bicycle repair tools, including a chain whip and freewheel remover tool to take off the freewheel and gain access to the lock nut that holds the axle in place. At first glance, this task may seem difficult, however, removing old wheel bearings and installing new bearings is a simple procedure that should take less than an hour to complete.

Things You'll Need

  • Freewheel remover tool
  • Chain whip
  • Cone wrench
  • Adjustable wrench
  • Mechanic's magnet
  • Wheel bearings
  • Axle grease
  • Small brush
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Instructions

    • 1

      Loosen and remove the axle bolts with the socket wrench. Remove the rear wheel from the bike frame. Remove the drive chain from the freewheel sprocket.

    • 2

      Insert the freewheel remover tool into the freewheel. Place the chain whip around the sprocket on the freewheel. Turn the freewheel remover tool to loosen the freewheel from the wheel hub. Remove the freewheel remover tool and chain whip from the freewheel. Unthread the freewheel from the hub.

    • 3

      Place the wheel flat with the drive side facing up. Fit the cone wrench on the cone in the wheel hub. Fit the adjustable wrench to the lock nut near the cone. Loosen the lock nut by turn the adjustable wrench counterclockwise while holding the cone wrench still.

    • 4

      Unscrew the cone, lock nut and any spacers from the axle. Set these items aside. Stand the wheel on edge. Carefully remove the axle from the non-drive side of the wheel. Wipe any grease from the axle and cones.

    • 5

      Remove the old bearings from both sides of the hub with the mechanic's magnet. wipe out the inside of the wheel hub using a clean cloth to remove any old grease. Check the bearing races within the hub and the cones for wear and replace them, if necessary.

    • 6

      Squirt a line of grease around the bearing races on both sides of the hub. Place the correct number of ball bearings into grease in the bearing races. Squirt another line of grease onto the bearings. Paint a thin layer of grease on the threads on the axle.

    • 7

      Insert the axle through the non-drive side of the hub. Thread the cone, spacers and lock nut onto the threaded end of the axle. Lay the wheel flat with the drive side facing up. Fit the cone wrench onto the flats on the cone. Fit the adjustable wrench onto the lock nut. Hold the cone wrench still and tighten the lock nut.

    • 8

      Rattle the axle to verify there is no play between the wheel hub and the axle. Thread the freewheel onto the axle. Place the drive chain on the freewheel sprocket. Replace the wheel on the frame of the bike. Replace and tighten the wheel axle nuts. Ride the BMX bike to tighten the freewheel.