Assault Air Bike, How to Replace the Short Chain, Crank to Hub, Right Side

Learn how to replace the short chain on your Assault Air Bike. The short chain is on the user's right side of the bike. The chain connects the crank sprocket and the small hub sprocket. This chain is also known as the primary stage chain. The steps to replace the chain are the same for the Classic, Pro, and Elite Assault bike models.

Part Discussed:

Tools Needed:

  • 8mm Hex Wrench
  • 15mm Ratchet Wrench
  • 10mm Ratchet Wrench
  • Phillips Screwdriver
  • Needle Nose Pliers
  • Crank Puller (22mm)
  • Crescent or Adjustable Wrench


  1. Using the 8mm Hex wrench, remove the crank-fixing bolt from the right pedal crank arm.
  2. Thread the crank puller into the crank arm and firmly tighten the top section using the crescent or adjustable wrench. First time using a crank puller? Watch our video about how to use a crank puller. Note: If you do not tighten the tool enough, the threads tend to strip and will ruin your tool or crank arm, if not, both.
  3. Using the crank arm for support, loosen the bottom section of the crank puller with the crescent wrench. If your crank puller has a built-in handle, you will turn the handle on the tool towards the right. This tightens the crank puller against the crank. As you continue to turn the handle, it pulls the arm free from the shaft.
  4. Separate the crank arm and pedal assembly from the bike.
  5. Remove the outer wave washer and set it aside.
  6. Lower the right upright arm clockwise and the left end counter-clockwise. You want the right upright arm resting on the ground and the linkage arm hanging straight down.
  7. Remove the inner wave washer from the bell crank spindle.
  8. Using the Phillips screwdriver, remove the 4 screws from the right chain cover. The fourth screw is in the bottom of the chain cover. You must tilt the bike to access the screw.
  9. Remove the chain cover.
  10. Rotate the right chain until you identify the master link.
  11. First, remove the spring clip off the master link using the needle nose pliers.
  12. Next, remove the remaining pieces of the master link from the chain. Remove the flat plate and the backer plate with pins.
  13. Remove the chain.
  14. To make connecting the new chain easy, use the 15mm and 10mm ratchet wrenches to loosen the sprocket tension. Use the 15mm ratchet wrench to loosen the hub axle nut. Use the 10mm ratchet wrench to loosen the tension nut.
  15. Make sure the master link is removed from the new chain. Feed the new chain around the crank sprocket and the small hub sprocket.
  16. Join the new chain with the backer plate and fasten the flat plate to the opposite of the chain. Install the spring clip. Reverse of how you removed the master link.

      Tech Tip

    Use the teeth of the chain sprocket to hold the ends of the chain while installing the master link.

  17. Confirm the new chain is rotating in a straight line around the crank sprocket and small hub sprocket.
  18. Check tension by lifting on the chain. The proper tension for the short chain is 5/16" of movement. Adjust the position of the chain tensioner nut for proper chain tension. Turn the nut clockwise to tighten the chain. Turn the nut counter-clockwise to loosen the chain.
  19. Once proper chain tension is set, re-tighten the 15mm nut on the hub axle. Ensure proper alignment of the crank sprocket and small hub sprocket remains.
  20. Carefully re-install the right chain guard onto the frame.
  21. Using the Phillips screwdriver, tighten the 4 screws of the chain guard in place.
  22. Re-install the inner wave washer onto the bell crank spindle.
  23. Now raise the right upright arm counter-clockwise and the left end clockwise returning the upright arm to its vertical position. The linkage arm bearing will be aligned with the bell crank spindle.
  24. Place the outer wave washer on the bell crank spindle.
  25. Re-install the right crank arm and pedal assembly. Make sure the crank arms are in opposite positions of each other.
  26. Tighten the crank-fixing bolt.
  27. Check the operation of your bike to ensure all parts are working as expected.
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