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Crank Removal & Installation- ISIS Drive or Octalink

Typical Tool and Supplies Required:

This article will discuss the removal and installation of crankarms on the round, splined type spindles. These are the ISIS Drive® or Shimano® Octalink types. For service of square-tapered type crankarms, see Square Tapered Spindle Type crankarms.

NOTE: There is a crank-spindle interface called "power spline" that uses a spline spindle. The crank bolt is an 8mm thread. Because the hole in the spindle is small, use the CCP-22 or CWP-7 for this crank, the same tools for a square spindle.

The oversized pipe billet splined spindles are round at the ends rather than square shaped. A series of internal splines in the crank are mated to external splines on the spindle. The cranks are held tightly to the spindle by tension from the crank bolt. Certain road and MTB models of Shimano® cranks uses an 8-spline design called Octalink®.

Octalink type crankarm
Octalink standard from Shimano®

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.

 

ISIS Drive crank
ISIS Drive standard

For all types of cranks, the first step of removal is to turn the crank bolt counter-clockwise. The crank bolt may simply come out of the spindle and crank. In this case, inspect inside the crank for the end of the spindle. Remove any washer seen inside. If the crank has a square hole, or if the bolt diameter is 8mm (about 5/16"), see Square Spindle-Type Crankarms.

Splined or "pipe billet" cranks will have a round hole in the crank where it meets the spindle.

One-Key Release ("self extracting")

Some cranks are sold with a "one-key release" or "self extracting" system. No crank remover is required. Leave the retaining ring ("dust cap") in place and turn the crank bolt counter-clockwise.

For more detail, see Self-Extracting Crank Systems.

 

One-Key-Release System
One-key system with pin holes in retaining cap


One-key system with hole fitting in retaining cap

Crankarm Removal-Non-One-Key-Release Type

For oversized pipe billet crankarms not using the one-key-release system, such as some ISIS Drive® and some Shimano® systems, use Park Tool CWP-7, or CCP-44. These removers use a large rotating tip that fits over the end of the spindle.


CCP-44 and CPW-7 crank removers

Procedure for crank removal:

 

  1. Remove crankarm bolt and any washer inside the arm.
  2. Unthread nut from handle stud of CCP-44 or CWP-7 until the tip is flush with the nut. This allows tool to have full thread contact inside the crank.

  3. Thread nut into crankarm and tighten with wrench until snug. If nut is not completely threaded into crankarm, the threads of the arm or nut may be damaged.
  4. Thread handle stud into nut. When resistance is felt, continue threading handle stud into nut until crankarm is removed.
  5. Repeat process on other arm.

Crankarm Installation

Use care when installing the crankarm to the spindle so splines match correctly. Crankarms using the one-key-release system make it difficult to see how the arm is fitting to the spindle. A forced mismatch on the splines can damage the arm. Splined type crankarms without the one-key system allow easy viewing of the spline fit. The spline pattern on the spindle consists of a series raised splines separated by flutes or recesses, at the minor diameter.

Align spline at 12:00

Keep the raised spline aligned at the top 12:00 position.

a. Lubricate inside spindle threads with grease or anti-seize. Also lubricate splines on spindle.
b. Rotate pipe billet spindle so one spline aligns to top dead center, at the 12:00 position.
c. Position right crankarm on to spindle so arm points straight down at the 6:00 position. Place crankarm on spindle and carefully thread bolt into spindle. View opposite side of spindle and check that a narrow spline is aligned to top dead center. Threading should continue without resistance until crankarm visually covers spindle splines.
d. Tighten bolt fully. If possible use a torque wrench and secure to 305-391 inch-pounds.
e. Align left arm so it points directly opposite from right arm. Thread bolt into spindle and tighten fully.

Tighten crankbolts