How to Take the Arms Off a One-Piece BMX Bike Crank

A one-piece bike crank is a crank that has the two arms of the crank and the crank fused together into one piece, so the arms cannot come off the crank. A three-piece bike crank has the arms bolted to the crank at the spindle, so they can be removed from the crank separately. So, you cannot take the arms off a one-piece crank, and if you wish to replace a one-piece crank, you must remove the entire crank from the bike.

Things You'll Need

  • Wrench
  • Flat head screwdriver
  • Hammer
Show More

Instructions

  1. Removing the Arms from a Three-Piece Crank

    • 1

      Remove the bolt that holds the arms to the spindle. This bolt should be located in the center of the two arms. Use the wrench to do this.

    • 2

      Loosen the pinch bolts with the wrench. These are located on either side of the crank arms.

    • 3

      Remove the arms and the spindle.

    Replacing a One-Piece Crank

    • 4

      Remove the left side pedal using the wrench to undo the pedal nut. Loosen the large nut where the crank and frame meet and remove the washer underneath.

    • 5

      Remove the adjusting cone by turning the cone nut clockwise. This may have to be done with a flat head screwdriver and hammer. Place the screwdriver in the notch of the cone nut and tap it with the hammer.

    • 6

      Remove the bike chain by tilting the crank. Remove the crank through the frame opening.

    • 7

      Slide the arm of the new crank into the frame and push it into the pedal. Replace the adjusting cone. Replace the washer under the nut on the bike frame and tighten the nut into the crank handle.

    • 8

      Replace the pedal using the wrench.