Gear Mech Conversion

Contents

What you can expect to find on this page

The process of converting an internal gear mech to an external gear mech is described below.

Advantages of the external gear mech compared to the internal version: the shifter cables run uninterrupted from twist shifter to cable box, so the need for a separate cable stop is eliminated. Another advantage is that regular internal shifter cables (1.1mm stainless steel), can be used, which are available in bicycle shops all around the world.

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Converting the gear mech is usually only necessary, when mounting the SPEEDHUB to a different bicycle frame. It is not routine work and we advise that this work is completed by a professional bicycle workshop.

Video workshop

Disassembly of the axle-ring

One-piece axle-ring

The one-piece axle-ring was mounted on all internal gear mech versions until the beginning of 2003 (up to serial number 25300). This type of axle-ring is secured to the gear-unit with six axleplate screws. The cable guides of the one-piece axle-ring remain fixed to the axle-ring. This can be seen once the axleplate has been removed.

Regardless of which axleplate is mounted, the axleplate must be removed by unscrewing all six of the axleplate screws (M4x25 - Torx TX20).
 

Rest the wheel on a flat surface with the axle-ring facing up and the cable guides facing to the right. Rock the axle-ring from side to side whilst pulling it upwards in order to loosen it from the hub.
 

Tip

Should the axle ring not loosen by hand, use a pipe wrench to hold the axle ring tight (place cardboard between the axle ring and the pipe wrench). Rock the axle ring from side to side with the pipe wrench, whilst pulling it upwards in order to loosen it from the hub.

Quick-change axle-ring

The quick-change axle-ring is secured to the gear-unit with five axleplate screws. The axle-ring remains secured to the gear-unit with one more screw and the cable guides seated within black nylon cylinders rest in the axle-ring. This can be seen once the axleplate has been removed.

Regardless of which axleplate is mounted, the axleplate must be removed by unscrewing all five of the axleplate screws (M4x25 - Torx TX20).

Rest the wheel on a flat surface with the axle-ring facing up and the cable guides facing to the right. Pull the cable guides with the nylon cylinders and the cable pulley upwards and out of the axle-ring.
 

Remove the axle-ring screw (M4x20 - Torx TX20) and rock the axle-ring from side to side, whilst pulling it upwards in order to loosen it from the hub.
 

Procedure after removing the axle-ring

Attention

The wheel must not be laid on the axle ring side once the axle ring has been removed because:

a. Oil could leak out of the holes.
b. The two freewheel springs could fall out of the locating peg holes.

Shift the gearbox into gear #14 by turning the hexagonal peg with an 8mm wrench carefully in an anticlockwise direction to the end stop.

Hold the aluminium nut on the sprocket side with a 17mm wrench to prevent the axle from moving, whilst selecting the gear.

Mounting the external gear mech

Before installing the external transfer box, check whether both freewheel springs are in the holes provided.

Place a new paper gasket over the locating pegs of the external transfer box, so that all holes meet up with corresponding screw holes of the axle-ring. The smaller seal sits in the recess on the rear side of the axle-ring.

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The grub screw under the External Gear Mech should be fitted in the correct position, see Grub screw of the External Gear Mech.

Mount the external transfer box onto the gearbox.

Place the cable pulley over the hexagonal peg of the external transfer box and then rotate it until the two screw holes sit on the center line F, as shown in the diagram above. Hold the cable pulley in this position.
 

Insert cog D over the hexagonal peg E with the toothing facing outward. There is one mounting position out of the possible six, where the teeth of the cog D and the sprocket C line up. In this position the screw holes of the cable pulley remain as close as possible along the center line F. This position is the correct position. It may be neccessary to turn the cable pulley lightly to the left or right to allow for an easier assembly.
 

The five other mounting positions result in the screw holes of the cable pulley being substantially more out of line with the center line F. In this case, remove the cog D and try the next mounting position.
 

Apply a small amount of grease between the cog D and the external transfer box. Remount the axleplate and secure it in the correct position with the five axleplate screws (M4x25 - Torx TX20, tightening torque 3Nm/25” lbs.).

Further steps for mounting the external gear mech can be found in chapter external gear mech.

Attention

The smaller side of cog D must always be mounted into the external transfer box facing inwards. When cog D is wrongly mounted, the axleplate will clamp the internal shifting shaft, causing operational problems and damaging internal seals.

Information on the axle plate alignment can be found here:

OEM/OEM2

Long torque arm

You can find out how to mount a brake disc here:

Brake Rotor Installation

Grub screw of the External Gear Mech

All gear hubs built after Serial Number 47000 and equipped with an external gear mech have an M4x8 grub screw mounted into the sixth threaded hole of the axle (it helps to prevent potential oil leaks). Therefore, the external gear mech can only be properly fitted in one position (PFig. 2) over the axle.

The grub screw on hubs with a Serial Number between 47000 and 48500 lies flush (external gear mech without a blind hole).

On hubs with the Serial Number 48501 and over, this grub screw pertrudes by approx. 2mm (external gear mech with a blind hole).

The blind hole B must be located directly over the grub screw A. When using an external gear mech without a blind hole B, the grub screw must be screwed flush into the axle.

The paper gaskets should then be fitted so that all the holes meet up with the corresponding screw holes of the axle.

To control that the mounting is correct, the screw C must be screwed smoothly approx. 4 complete turns into the hub without force. Afterwards, the installation of the axle plate including all the screws can be completed (3 Nm).
 

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If an axle plate screw cannot or only with force be screwed into hole C, then it must be checked that the grub screw A is not sitting directly behind this hole. If this is the case, then the external gear mech must be disassembled turned around 180° and mounted again in this position. The grub screw stays in its original position (2 mm pertruding).
 

Attention

If the external gear mech should be falsely mounted, then the fitting of an axle plate screw into hole C would cause the grub screw A to be forced into the axle. This in turn will lead to a complete blockage of the gearbox.

The removal of the grub screw is only necessary when converting the external to an internal gear mech, or when working with the hub seal replacement tools. The external gear mech should never be removed from the gearbox without good reason!