When pedaling, the flywheel makes noise.


Some noises the flywheel may make are normal, while other noises are troublesome and should be checked. See the section below for a list of normal sounds that the flywheel can make. 

Before troubleshooting

Some noise is normal. Read the points below before continuing to the troubleshooting section:

  • The flywheel may make a light beeping noise that is most notable when pedaling very slowly or coasting - this is the control system frequency and is normal - there are no additional steps to take. This noise should be faint and difficult or impossible to hear when pedaling the bike normally.
  • There may be a faint or somewhat loud "tick" that occurs once per flywheel revolution. It is likely this noise will go away with some use and is not an issue to the functionality of the bike unless your bike reports no cadence. 
  • When coasting, there may be a light freehub-like clicking, similar to coasting on a normal bike. This is the freehub bearing and is to be expected and not a reason for concern.

Loud banging, scratching, "rock tumbler," knocking, or other abnormal noise should be addressed in the following Troubleshooting section.


Depending on the noise you are hearing, follow the different steps below to troubleshoot. 

Grinding accompanied by difficult pedaling

Pedal the bike in reverse. If the bike is easy to pedal in reverse, skip this section and move on to the next one.

If there is resistance to pedaling the bike in reverse, it's possible the belt tensioner is loose or not attached. There is a potentially simple fix to this issue included in the next steps that you may want to try.

Repair guide

  1. Remove the front drive side flywheel cover by removing the two (2) 3 mm bolts, as shown below:StagesBike drive side cover
  2. Pull this cover away from the bike and then rotate it to remove it from the two posts connected to the right leg:StagesBike drive side cover moving inward
  3. Check to see whether the part indicated below is present, and if so, whether it is tight against the frame by trying to wiggle it - it should not be easy to wiggle:Arrow pointing to the internal belt tensioner
  4. If this part is missing, falls out when you remove the front drive-side cover, or is loose, your noise issue is likely caused by this. This part keeps tension on the belt so the crank and flywheel turn in unison. Stages can send a technician out to repair this, or you can do so yourself if the nut and metal bracket can be found. Move onto the next step to repair on your own or contact our support team by submitting a new ticket.
  5. Tighten the bracket and nut against the frame slightly using a 7 mm wrench.
  6. Loosen the 14 mm nut on the flywheel axle (pictured below) so the flywheel can slide forward:Arrow pointing to the internal belt tensioner bolt
  7. Tighten the 7 mm nut one full turn and pedal the bike. A loose belt will have a slack feeling when pedaling from stationary, and a too-tight belt will make a lot of ambient noise when pedaling hard. The tension of the belt can be checked by hand under the plastic belt guards. There should be about 1/2'' or 12-15 mm of deflection near the sprocket. Adjust this nut and check the feel of the bike until you are satisfied.
  8. Make sure the Flywheel is in alignment after you adjusted the 7 mm nut to your liking. 
  9. Tighten the 14 mm axle nut.
  10. Replace the front drive side flywheel cover and reinstall the two (2) 3 mm bolts.

Scratching, grinding, or banging in rhythm with the flywheel speed

If the flywheel makes a very similar sound with every revolution, it's likely that the flywheel is rubbing against the belt cover here:     Bottom cover of StagesBike

To check if this is the problem:

  1. Pedal the bike so the flywheel is spinning and making the noise.
  2. Get off the bike to the non-drive side belt guard and hold the pedal with your right hand to keep it from spinning.
  3. Push on the Stages logo on the belt guard:Hand pressing inward on non-drive side shroud cover
  4. If the noise stops as you push, follow the steps in the next section to repair the issue.

Repair guide

You can create a ticket to have this issue resolved by a technician or follow the simple steps below to fix this issue yourself:

  1. Remove the two (2) 3 mm bolts from the front drive side flywheel cover.StagesBike front drive side cover
  2. Check that the two screws indicated in the picture below are holding the belt guard to the right leg. If the belt guard is not installed correctly, then these two screws can push the belt guard into the flywheel.StagesBike belt guard internal bolts
  3. Remove the 7 belt guard screws and slide the entire belt guard towards the rear of the StagesBike in case it is being pushed into the flywheel. Full removal of the shroud cover is not needed.Arrows pointing to the 7 screws on the SB20 shroud cover
  4. Remove and reinstall the two screws below so the belt guard is no longer being pushed into the flywheel. Slide the belt guard back forward into place and reinstall the 7 belt guard screws.StagesBike belt guard internal bolts
  5. Replace the front drive side flywheel cover and reinstall the two (2) 3mm bolts.

Random rock tumbler noise, or seemingly random or sporadic knocking, clicking or banging.

If noise continues, remove the non-drive side flywheel covers to ensure that the stator bolts are tightened.

Repair guide

  1. Unplug the bike prior to removal of covers for your safety. Vital electronic components for the bike are underneath the covers. 
  2. Remove the two (2) 3 mm screws from the non-drive side front plastic flywheel cap.StagesBike front non-drive side cover
  3. Remove the two (2) 3 mm screws on the non-drive side rear plastic flywheel cap and remove the cap; set aside for reassembly later.StagesBike rear non-drive side cover
  4. Once visible, verify the two (2) 5 mm stator stay bolts are tight. Then check the 6 mm stator set screw above the bracket for tightness as well. Arrows pointing to two stator boltsArrow pointing to the top stator bolt
  5.  After verifying tightness, re-install both flywheel covers. 

If these fixes do not resolve the issue, and you have ruled out all cases in the Before troubleshooting section, it is likely your flywheel needs a replacement. Submit a new support ticket to schedule a replacement and technician.