How to Install a Euro Bottom Bracket on a BMX Bike

Euro bottom brackets, also referred to as British standard bottom brackets, are defined as having standard- sized threads and a diameter of either 68 or 73 millimeters. The majority of modern road, mountain and BMX bikes in production use this type of bottom bracket. The thread-less bmx standard is called a "one-piece" bottom bracket. The threaded cups of a euro bottom bracket tighten in a left-hand and right-hand opposite fashion. The left side of the bracket tightens clockwise, while the right tightens counter-clockwise.

Things You'll Need

  • Thick lithium grease
  • Euro bottom-bracket, cups and spindle
  • Sleeve and spacer washers of correct diameter
  • Adjustable wrench
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Instructions

    • 1

      Grease all threads on the frame and cups. Size the bottom bracket outside the frame, adjusting for the fit with spacer washers between the sleeve and cups. The cups need to fit flush against the frame. Bring your bottom bracket and spindle along with you to a bike parts supplier to help find the right spacers and sleeve for your needs.

    • 2

      Install a cup by gently hand-tightening until it is flush against the surface of the shell. Apply minimum pressure with an adjustable wrench to secure it in place. Grease the crank spindle and slide it through the secured cup and install necessary spacers and sleeve from the opposite end of the spindle.

    • 3

      Install the second cup using the same hand-tightening method as before. When the cup is flush against the frame, gently apply pressure with an adjustable wrench.

    • 4

      Check to make sure both cups are flush and secured to the frame.