The side the belt is riding to is a little loose.
Your treadmill may have come with an allen key for this.
at the rear of your treadmill there are 2 adjustment bolts.
Right and left on your roller. Run you treadmill at 3 mph. Turn the bolt 1/4 turn to tighten, until your belt goes back to center.
Also look at the front roller if it has a plastic sleeve, it can come loose and travel off the roller, and take the belt with it.
I also have a video on belt adjustments at
www.mindbites.com/person/214-Mark
Mark Peterson, April 2008
