Zwift Cog replacement - removal and installation

This article describes removing and installing a Zwift Cog on a KICKR, MOVE, or CORE's stock Shimano/SRAM HG 11 speed freehub.

Required Tools:

• Chain whip (Park Tool SR-12.2 or similar) OR cassette vise/pliers (Pedro's Vise Whip II or Park Tool CP-1.2)
• Cassette lock ring tool (Park Tool FR-5.2 or similar)
• Adjustable wrench or socket for 1 inch (to accommodate the cassette lock ring tool)

Removal

1. Remove the quick release and drive side QR adapter or thru axle spin cap, if present.
   
   
   
2. Secure the chain whip, cassette vise, or pliers around the cog with the handle(s) toward the front of the trainer. If using a chain whip, drape the chain over the top of the cog from back to front. This will allow you to apply downward force on the tool to prevent the cog from spinning backward when loosening the lock ring.
   
   
   
3. Insert the cassette lock ring tool into the lock ring fully, and secure the wrench to the lock ring tool.
   
   
   
4. Push or pull the cassette lockring tool counter-clockwise while using the chain whip or cassette vise/pliers to brace the cog in place. You will hear a ratcheting/notching noise as the lock ring breaks free.
   
   
5. Once loose, you can remove the wrench and use the lock ring tool or your fingers to unthread the lock ring by hand.
   
   
6. When the lock ring is gone, gently pull the Zwift cog off of the freehub.
   

Installation

1. The Zwift Cog consist of 4 parts --
   1. inner bumper (larger, with a concave back and a chamfered and shelved front)
   2. 14 tooth cog (with an integrated spacer at the back)
   3. outer bumper (smaller, solid, with a chamfered and shelved rear)
   4. lock ring
      
2. Start by sliding the inner bumper, hollow side first, onto the freehub body.
   
   
3. Slide the 14 tooth cog, spacer side first, onto the freehub body, so that the spacer fits into the cavity.
   
   
4. Slide the outer bumper, shelf and chamfered side first, onto the freehub body.
   
   
   
5. If installed correctly and viewed from behind, the cog will sit in a symmetrical channel with vertical walls that taper away from the cog.
   
   
   
6. Thread the cassette lock ring on by hand.  Be careful not to crossthread the lock ring. One good way is to rotate the lock ring counter-clockwise until you feel a notching sensation as the first threads fall past one another. Then start rotating clockwise.
   
   
   
7. Use cassette tool to snug the lockring, bracing the large pulley wheel with your hand.  Once snug, tighten another 1/4 turn. Do not exceed 15Nm to avoid damaging the plastic bumpers.
   
   
   
8. Install the thru axle drive side spin cap or quick release adapter and quick release.
   

Failing to install the drive side spin cap when using a thru axle bike will result in a frame spacing issue.

Installing the Zwift Cog from the Zwift Cog + Click Upgrade kit

The Zwift Cog in the kit comes pre-installed on a Zwift Hub freehub body, which is not compatible with the KICKR CORE. Using the Zwift freehub body with the CORE may damage the CORE. To use a Zwift Cog on a CORE, you will need to remove the Zwift Cog assembly from the Zwift Hub freehub body and install it on the CORE’s stock freehub body.

Required Tools

• Chain whip (Park Tool SR-12.2 or similar) OR cassette vise/pliers (Pedro's Vise Whip II or Park Tool CP-1.2)
• Cassette lock ring tool (Park Tool FR-5.2 or similar)
• Adjustable wrench or socket for 1 inch (to accommodate the cassette lock ring tool)
  
  

Zwift Cog Removal from Zwift Hub freehub body

1. Drape the loose chain over the cog and place the cog onto the captured chain section of the chain whip with the handle oriented to the right of the Cog assembly.

2. Insert the cassette lock ring tool into the lock ring.

3. Rotate cassette lock ring tool counter-clockwise to loosen the lock ring.

4. Continue with Step #5 in the Removal steps above, and continue to the end. Set the Zwift Hub freehub body aside.

Video Demonstration