How to Install the Bottom Bracket of a Hollowtech

Hollowtech is Shimano Cycling's name for its particular design of bicycle cranks. These cranks, which play a central role in the drive train, work in conjunction with a part called a bottom bracket. Both ends of the bottom bracket house a series of bearings, and these bearings allow the axle portion of the crank to turn smoothly and efficiently. Installing the bottom bracket is one of the first steps to installing a Hollowtech crank.

Things You'll Need

  • Waterproof bicycle grease
  • Shimano TL-FC32 bottom bracket tool
  • Measuring tape (as needed)
Show More

Instructions

  1. Road Bike Bottom Bracket

    • 1

      Grab both ends of the Hollowtech bottom bracket. One end is marked with an "R" and the other with an "L". These letters designate right and left, respectively. The right end corresponds with the drive side of the bicycle. The left end corresponds with the non-drive side of the bicycle.

    • 2

      Apply grease to the threads around each end of the bottom bracket.

    • 3

      Thread the right end of the bottom bracket through the right side of the bottom bracket shell, at the bottom of the bicycle frame. Turn this end of the bottom bracket counterclockwise to tighten. Turn by hand as far as possible.

    • 4

      Attach the TL-FC32 wrench around the edge of the right side of the bottom bracket. Use the wrench to tighten the bracket fully.

    • 5

      Thread the left end of the bottom bracket into the left side of the bottom bracket shell. Turn this end of the bottom bracket clockwise to tighten. Tighten by hand as much as possible.

    • 6

      Use the TL-FC32 wrench to fully tighten the left end of the bottom bracket.

    Mountain Bike Bottom Bracket

    • 7

      Use a measuring tape to measure the width of the bottom bracket shell at the bottom of the bicycle frame. Expect a measurement of either 68 or 73 mm. Remember the measurement.

    • 8

      Note which type of front derailleur is installed on your bicycle. This derailleur is located above the bottom bracket, on the bicycle frame, and is attached to the frame either by a clamp or lower bracket.

    • 9

      Grease the threads on each side of the bottom bracket. Note that one side is labeled with an "R" and the other with an "L". These letters designate right and left, respectively.

    • 10

      Note the spacers included with your Hollowtech bottom bracket. Each spacer measures 2.5 mm in width.

    • 11

      Choose the amount of spacers required. For 68 mm bottom bracket shells with a clamp-style derailleur, use one spacer on the left side of the bottom bracket and two spacers on the right side of the bottom bracket. For 73 mm bottom bracket shells with a clamp-style derailleur, use one spacer on the right side of the bottom bracket. For 68 mm bottom bracket shells with a bracket-style derailleur, use one spacer on both sides of the bottom bracket. For 73 mm bottom bracket shells with a bracket-style derailleur, do not use any spacers.

    • 12

      Slide the required spacers onto the proper end of the bottom bracket. For 68 mm bottom bracket shells with a bracket-style derailleur, fit the right side spacer between the derailleur bracket and the bicycle frame. All other spacers can slide directly onto the proper side of the bottom bracket.

    • 13

      Thread the right side of the bottom bracket into the right side of the bottom bracket shell counterclockwise. Tighten the bottom bracket by hand as much as possible.

    • 14

      Attach the TL-FC32 tool around the right side of the bottom bracket, and tighten the bracket fully.

    • 15

      Thread the left end of the bottom bracket into the left side of the bottom bracket shell clockwise. Tighten the bottom bracket by hand, before tightening it fully with the TL-FC32 tool.