Tip & How-To about Stairmaster Exercise & Fitness

Drive Hub, Spring Pulley & Chain Replacement for Steppers

Video about the Drive Hub Replacement Procedure for Stairmaster Steppers

  • This videocovers replacing the spring pulley, the step chain and the drive hub assembly on the Stairmaster steppers
  • Tools needed:
    • Snap Ring Pliers
    • Tip Kit for Snap Ring Pliers
    • Socket Wrench
    • 7/16" Socket
    • 7/16" Wrench
    • Needle Nose or Standard Pliers
    • Safety Goggles
  • Begin by disconnecting the spring
  • Do this by pulling up on the spring and unhooking the spring from the frame post
  • Next, using the snap ring pliers and proper tips, remove the snap ring from the spring pulley shaft
    **Important: Be sure to wear safety goggles when working with snap rings**
  • Remove and inspect the spring pulley for any flat spots replacing the pulley if necessary
    • Flat spots develop over time and can result in roughness in the pedals
  • On the side that the pulley was just removed, slowly press the pedal down
  • Remove the step chain retainer brackets (if equipped) using the 7/16" wrench, 7/16" socket and socket wrench
  • Once the retainer bracket is removed, the spring can be lifted up over the drive sprocket and disconnected from the chain
    • The spring is opened at one end to allow for maneuvering over the link
  • Using the standard or needle nose pliers, remove the master link attaching the step chain to the pedal arm
    • Place one jaw of the pliers against the open end of the clip (if installed correctly, the open end of the clip is opposite the direction of chain travel) and the other jaw of the pliers against the far side of the nearest rivet coming through the keeper link; and squeeze pliers together
    • This should pop the clip free allowing you to remove it from the master link
    • Next remove the link bar
    • Finally remove the master link disconnecting the chain from the pedal arm
  • Inspect the new step chain making sure all the chain links flex
    • Manufacturer recommends lubricating the step chain with 30W motor oil using a clean rag to remove any excess
  • Attach the new step chain to the pedal arm reversing the steps taken to disconnect the chain
  • Relieve tension on the opposite spring by lifting up on the spring and unhooking it from the frame post
  • Slowly press the pedal down
  • Feed the spring around the pulley and lift the chain up over the sprocket to move it out of the way
  • Disconnect the remaining two bolts from the drive hub assembly
  • Lift the drive chain over the sprocket and pull the drive hub from the frame
    • As the drive hub assembly starts to develop problems, you may feel clicking, hear some grinding sounds, or a pedal may stick in one position (which usually happens on one side); All of which are indicators of a worn drive hub assembly
    • The drive hub can be replaced as a complete unit
      • The drive hub consists of (3) sprockets
        • Two one way clutch sprockets that drive in one direction and slip in the opposite direction which are for the step chains
        • A larger sprocket that spins either direction and is for the drive chain
    • An inspection of the drive hub can help determine need for replacement
          • If either of the one way clutch sprockets slip in both directions, they need replaced
          • If there is a catch in any of the sprockets in any position, then it likely needs replaced
  • Reinstall the drive hub the same way it was removed
  • Slip the drive chain over the drive sprocket before mounting the hub assembly to the frame
    • The drive hub assembly on the SC916 stepper only has 4 bolt positions. The drive hub assembly on the 4400 and 4600 steppers has bolt holes all around the hub allowing the hub to be rotated for chain tension adjustment. The SC916 stepper has a preset tension and the adjustment is no longer necessary
  • Once the drive hub is bolted to the frame, reinstall the step chains on each side
  • Place the free end of the step chain (opposite the pedal arm connection) up over the step chain sprocket
  • Lift up on the pedal and pull down on the step chain
  • Place a hand on the sprocket keeping the step chain from feeding back and allowing the pedal to drop
  • Grab the spring with your opposite hand and join the spring to the step chain
  • Once the spring is attached to the chain, press the pedal down again
  • Reinstall the spring pulley and the snap ring onto the pulley shaft
  • Lift up on the pedal and pull the spring to route through the pulley, hooking the spring onto its frame post
  • Repeat these steps to attach the step chain and spring on the opposite side
  • Reinstall the step chain brackets (if equipped) making sure all bolts face the same direction
  • This concludes the video demonstration of replacing the drive hub, spring pulley and chains on the Stairmaster steppers

Spring Pulley Chain Drive Hub Replacement Video for Stairmaster Stepper...

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1 Answer

stairmaster 4000 pt


Replacement Parts for Fitness Exercise Equipment at SPORTSMITH My pedals on my Stairmaster are frozen in the top position, what do I check?
  1. Remove the alternator belt. IF pedals drop, problem is in alternator. IF NOT,
  2. Remove the drive chain, IF pedals drop, problem is in transmission, IF NOT,
  3. Problem is in hub assembly. Replace assembly.

Frozen Pedals in Top Position on Stairmaster Steppers

Nov 18, 2013 | Exercise & Fitness

1 Answer

Stairmaster 4400pt seems to have a slipping chain.


Replacement Parts for Fitness Exercise Equipment at SPORTSMITH

You can take the covers off and see if it is indeed the chain that is slipping, but in most cases, the drive sprocket is actually what is failing. The following link will take you the item that should rectify your issue.

Drive Hub for Stairmaster Steppers 4000PT 4400CL 4600CL 4400PT 4600PT...

Nov 04, 2010 | Stairmaster 4400 PT Stair Stepper

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