How to Repair Bicycle Bearings

Wheel bearings on bicycles can wear out from excessive miles, lose their seals and collect contaminants like dirt or water. When this happens, you must replace the wheel bearings. The bottom bracket hub is a sealed unit that you change out completely in one piece. Pitted bearings can cause damage to your hub if you don't change them. You can change your bearings in about an hour on both wheels with a few hand tools.

Things You'll Need

  • Bike stand
  • Freewheel puller
  • 15mm open-end wrench
  • 13mm open-end wrench
  • 17mm open-end wrench
  • Soft cloth
  • Grease
  • 1 set new bearings, 3/16-inch diameter
  • 1 set new bearings, 1/4-inch diameter
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Instructions

    • 1

      Put the bike in a bike stand. Loosen the quick release lever on both wheels and take off both wheels. Lay them out on a workbench on the side with the lever pointing down.

    • 2

      Unscrew the quick-release levers from both wheels. Pull out the skewers and set them aside. The skewers are the long axle-like rods that go through the center of the wheel.

    • 3

      Remove the gear cluster from the back wheel by turning it counterclockwise. If you can't remove it by hand, wrap the freewheel puller around the gear cluster. Push on the handle to loosen it. When it comes loose, take off the freewheel puller and lift off the cluster.

    • 4

      Pry off the rubber seal on the axle using a screwdriver. Slip a 15mm wrench onto the cone flats on the back wheel and a 13mm wrench onto the cone flats on the front wheel. The cone flats are located on the wheel axle closest to the wheel, the only place the wrench will fit. Place a 17mm wrench on the nut on top above the other wrenches. Turn it counterclockwise against the cone wrench on both wheels to loosen everything.

    • 5

      Stand the wheels up one at a time. Unscrew the locknut, cone and spacers. The locknut is located on the outside of the axle.The spacers are next in line, and then the cone is located nearest the wheel hub. Place them aside. Pull the axle out. The bearings should stay stuck inside the bearing race, the shiny, cone-shaped object. Remove all the bearings from both sides of both wheels with your fingers and set them aside.

    • 6

      Wipe the inside of both wheel races with a soft cloth to remove any residual grease. The wheel race is the shiny, cone-shaped housing on both sides of the axle that the bearings ride in; they are located on the outside of the hub and become visible after you take off the locknut, cone and spacers. Smear new grease on the inside of the hub where the bearings came out. Using your fingers, push the new ball bearings down into the grease one at a time. Use 3/16-inch diameter bearings on the front hub and 1/4-inch diameter bearings on the rear hub. Smear all the bearings with grease. Be gentle and make sure not to dislodge them.

    • 7

      Smear the axles with grease and slide them into their respective hubs. Replace washers, spacers and cones on both sides. Tighten everything using your fingers. Lay the wheels back down. Slide the cone wrench back on the cone flats on the outside of the axle below the locknut. Slide the 17mm open-end wrench on the back wheel and the 13mm wrench on the front wheel. Tighten everything clockwise. Slip the rubber cone seals back on and make sure they fit tight against the axle. Slide the skewers back into the axles and replace the quick-release knobs. Put the wheels back on the bike.