There should be equal space between the treadmill belt and the foot rails on both sides. Which side the belt slides to will determine how you do the repair. On almost all treadmills, you can re-center the belt by tightening the roller screw on the side the belt slides to or loosening the roller screw on the side the belt slides out of.
On almost all running machines, it is impossible to mistake the cylinder adjustment screws for anything else. These are two hex head screws at the very end of the treadmill, recessed into the leg rails on either side of the belt.
Which screw you adjust and whether you decide to tighten or loosen it depends on your brand of treadmill. If you are not sure which screw to adjust, refer to the owner's manual.
How to center the belt?
Stand on the side of the treadmill and run it at a speed of 3 km/h and watch it for at least two minutes. Does the belt start to center itself? If so, you may simply have a leveling problem. Use the leveling feet on the underside of the treadmill to level the unit. If the belt does not center after two minutes, the procedure of the back of the treadmill.
If the belt moves to the left, insert the key into the left bumper and turn it a quarter turn clockwise. Then insert the key to the opposite side and turn it counterclockwise. If the belt moves to the right, insert the key into the right bumper and turn a quarter turn clockwise. Then insert the key to the opposite side and turn it a quarter turn counterclockwise.
Watch the belt for at least 2 minutes to give it time to center. If it is not centered after these two minutes, repeat the process one more time.
We will get your treadmill in good condition