Remove the plastic cover on the front of the belt. About 6 screws. The cover lifts off. looking at mat as if walking on it you will see an adjustment bolt on right hand side. This moves the front roller. Loosen nut then adjust the bolt 1/2 a turn at a time. Turn one way and run mat slowly. Mat will move and center. If wrong way turn bot other way. When mat in desired place tighten nut at back to keep in place and return plastic cover.
vic
October 2009