Crank Removal and Installation: Three-Piece
This article will demonstrate removal and installation of three-piece cranks. It covers square tapered spindles as well as splined style such as ISIS Drive and Octalink.
Cranks connect the pedals to the bottom bracket spindle and are pressed tightly to the bottom bracket spindle which are held in place by force from well-torqued crank bolts or nuts. Cranks must be removed from the spindle to service the bottom bracket bearings or to replace the chainrings.
Crank pullers are used for the removal of basic three-piece crank types: square-type spindle arms, and splined-type spindle arms.
Square tapered spindles are made with a slight slope or taper. This shape creates a wedge as it is driven into the square hole of the crank. Adequate torque from the crank bolt is typically enough to keep arms from creaking. If a crank creaks even at full torque, remove and grease the pressed surfaces.
Cranks used with a loose bolt will result in movement and wear between steel spindle and the sqaure hole the crank. When the spindle end is no longer recessed inside the hole, the crank bolt can not apply pressure to hold the arm tight on the spindle. A worn crank will need to be replaced.
Certain road and MTB models of Shimano® cranks uses an 8-spline design called Octalink®. The oversized pipe billet splined spindles are round at the ends rather than square shaped. A series of internal raised splines in the crank are mated to recessed external splines on the spindle. The cranks are held tightly to the spindle by tension from the crank bolt.
Another standard is the ISIS Drive® (International Spline Interface Standard). The ISIS Drive® system uses ten splines of a different shape from Shimano®. The ISIS Drive® and Octalink® systems do not interchange for either cranks or spindles.
Cranks that are sold with a “one-key release” or “self extracting” system do not require a crank puller. For details on how to service these cranks, see our article on Crank Removal and Installation: Self-Extracting.
- Shift chain to largest chainring. This helps protect hands from chainring teeth.
- Remove crank bolt or nut by turning counter-clockwise.
- If no bolt is visible, remove dust caps. Some caps pry out and some thread out.
- Remove any washers inside the crank that were below the bolt/nut.
- Inspect crank bolt and select correct tool
- Turn threaded coupler of puller until it sits recessed in the hex fitting of the tool, taking care not to cross thread. This permits full engagement of 22mm thread into arm.
- Thread spindle driver of puller into arm. The 22mm thread fitting must be fully threaded into arm before pulling the arm.
- If spindle driver is not completely threaded and engaged into crank arm, the threads of the arm or nut may be damaged.
- Turn spindle driver clockwise. When driver meets spindle, resistance will be felt. Continue threading driver into puller until crank is removed.
- Unthread crank puller tool from crank.
- Use care not to skin knuckles when removing tool.
- Repeat process on other side.
- Grease or anti-seize under head and threads of bolts/nuts.
- For square tapered spindle, leave spindle clean of grease. Grease or anti-seize the splines of spline type spindles.
- Rotate pipe billet spindle so one spline aligns to top dead center, at the 12:00 position.
- Position right crankarm on to spindle so arm points straight down at the 6:00 position.
- Install right crank onto right side of spindle. Thread in bolt to spindle. Self-extracting models align tooth and groove of spindle and crank when installing.
- Tighten bolt fully to manufacturer’s specifications.
- The bolt may need 34 Nm to 50 Nm (300 to 450 inch-pounds) depending upon brand. Whenever possible, use a torque wrench for this installation.
- Align left arm so it points directly opposite the right arm. Self-extracting models align tooth and groove of spindle and crank when installing. Thread bolt into spindle and tighten bolt fully.
- Grease threads of dust cap (if any), and install snugly.
- Repeat process on other side