TABLE OF CONTENTS

• Overview
  • Tools required
  • Replacement parts required
• Replacement instructions

Overview

A step-by-step guide to replacing the flywheel belt tensioner on the Stages SB20 smart bike. 

• Estimated time required: 30 minutes

Tools required

• 3 mm hex key
• 6 mm hex key
• 7 mm wrench or socket
• 14 mm open-end wrench
• Torque wrench

Replacement parts required

• ASSY, BELT ADJUSTER (000-3512)

Replacement instructions

1. Unplug the bike.
   Remove the power connector from the bike behind the rear leg before starting the repair.
   
   
   
2. Remove the front plastic caps from the flywheel of the bike.
   
   Note: For the purpose of this article, the sides of the bike will be referred to as the Drive Side (side with belt) and Non-Drive Side to avoid confusion between the rider’s right/left (sitting on the bike) and the technician's right/left (facing the bike).
   
   Removal of the Drive Side belt guard cap is required, as is removal of the front and rear flywheel caps on the Non-Drive Side.
   1. Use the 3 mm hex key to loosen 2 screws and remove the front drive side belt guard cap; set aside for reassembly later.
      
      
      
   2. Slide the cap forward and rotate the cap away from the bike to remove it from the 2 shoulder bolts holding the cap in place. You may need to push on the cap to get the upper shoulder bolt to clear the cap.
      
      
      
   3. Repeat this procedure to remove the two flywheel caps on the non-drive side of the bike.
      
      
      
      
      
3. Using a 6 mm hex key, loosen the cap head set screw above the bracket on the non-drive side of the flywheel, about 1 turn.
   
   
   
   
   
4. Remove the flywheel tensioners from the axle.
   1. With a 14 mm box end wrench, remove the non-drive side and drive side axle nuts:
      
      
      
      
      
      
      
      
      
   2. With a 7 mm socket or wrench, loosen the nut on the end of the belt tensioner adequately to allow the end of the tensioner to clear the nose of the dropouts. Remove the tensioner from the axle and set it aside. Repeat for both sides.
      
      
      
      
      
5. Install the new tensioner(s) and adjust the belt tension
   1. Install the new tensioner(s) onto the axle, followed by the axle nut(s). Leave the axle nut(s) loose against the tensioner to hold it in place until the final adjustment is made. Tighten the 7 mm nuts evenly until the tensioner makes contact with the end of the dropout. Repeat for both sides.
   2. Once installed, adjust the 7 mm nuts on the drive side belt tensioner until there is about ¼” of play in the belt.  You can check the tension with your finger by pushing on the belt just behind the pulley.
      
      
      
   3. Adjust the 7 mm nut on the non-drive side tensioner so that the flywheel sits square in the dropouts. Gently rotate the flywheel counterclockwise to view how the belt tracks.
   4. Tighten the 14 mm axle bolts until snug. 
   5. Torque axle bolts to 22 ft·lbs or 30 N·m using a torque wrench.
   6. Use a 6 mm hex key to tighten the cap head set screw above the bracket on the left side of the flywheel. The bolt should not be too tight, but ensure there is no gap.
      
      
6. Give the bike a quick test ride to ensure the belt is tracking correctly and the drivetrain is operating smoothly.
7. Reinstall the belt guard cap and flywheel caps. 
8. Reinstall the drive side belt guard cap. If needed, push on the cap to clear the upper shoulder bolt head.
   
9. Reinstall the rear non-drive side flywheel cap.
   
   
   
10. Reinstall the front non-drive side flywheel cap.
    
    
    
11. Plug the bike back into the power block. 
12. Pedal the bike
13. Ride the bike to confirm it functions as expected, and you don't hear any unusual noises.