Belt is slipping:
If you take a step and it feels like the belt is slipping, it may need to be tightened up.
Using the larger hex wrench that came with your Tread, tighten up the back roller by
turning both screws (one on each side of the roller) clockwise, one full turn. If it still
feels like it is slipping, turn each screw a half turn until it stops slipping.