More times than not it is caused when the walking belt has moved off center and the sound that you are hearing is indicative of the belt rubbing on the side rail or cover.
- Firstly, ensure the treadmill is level.
- Start the machine and run it at around 5km.
- On both sides of the end of the treadmill you will find allen key bolts (you should have been provided the tool to turn these within your purchase).
- If the mat is drifting to the left, then tighten the left hand side bolt a quarter of a turn.
- Let it run for a around a minute to see if it centers.
- If it requires further adjustment, complete an additional quarter turn.
- Use this method visa-versa if the mat is drifting to the right.