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Removing and installing ISIS Drive® and Shimano® pipe billet spindle crankarms

Level of Difficulty: Novice  

Typical tools & supplies [1]

  • Wrench for crank bolt, typically 8mm. Some models may require 10mm.
  • Crank Remover
  • Grease

ISIS Drive and Octalink crank with CCP-4

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. See also Crank Tools.

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. Shimano® uses an 8-spline design called Octalink®. A different and non-interchangeable standard is the ISIS DRIVE® (International Spline Interface Standard). The ISIS DRIVE® system uses ten splines of a different shape from Shimano®. Again, the two systems do not interchange.

Spline type spindle

For all types of crankarms, the first step of removal is to turn the crank bolt counter-clockwise. Two things might happen. First, the bolt may simply come out. In this case, inspect inside the crankarm for the end of the spindle. Remove any washer seen inside. A square hole in the crankarm uses the square type spindle. In this case see Square Spindle-Type Crankarms. A round hole in the crankarm where it meets the spindle is the pipe billet type.


One-Key-Release System

The second possibility is the crankarm bolt presses back against a crankarm cap, or retaining ring, and the entire arm is pulled off. This is the case if the arm uses a One-Key-Release system. One-key-release systems use a metal cap threaded into the crankarm. This metal cap takes the place of the dust cap and surrounds the crankarm bolt head. To remove the crankarm, leave the ring in place. Turn the crankarm bolt counter-clockwise and the bolt backs against the ring pulling the arm from the spindle. Both oversized pipe billet spindle and square type spindle system may come with the one-key-release system, and both are removed the same way. It can occur that the one-key-release cap or retaining ring comes loose. To secure the ring use the Park Tool SPA-2 pin spanner. No crank extractor is required for the one-key-release system, as seen below.

CCP-4 and CWP-6

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-6, or CCP-4

Crankarm removal - non-One-Key-Release type

1 Remove crankarm bolt and any washer inside the arm.
2 Unthread nut from handle stud of CCP-4 or CWP-6 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

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

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.

1 Grease threads inside bottom bracket spindle. Grease splines on spindle.
2 Rotate pipe billet spindle so one spline aligns to top dead center, at the 12:00 position.
3 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.

Tighten crankbolts

4 Tighten bolt fully. If possible use a torque wrench and secure to 305-391 inch-pounds.
5 Align left arm so it points directly opposite from right arm. Thread bolt into spindle and tighten fully.

Suggested Park Tools