Remove the NordicTrack elliptical machine cover using a Phillips head screwdriver.
Use an Allen wrench to turn the pulley bolts in a counterclockwise direction to release the drive belt tension. You can now pull the drive belt free from the elliptical machine and slide the new one on.
Use your Allen wrench to tighten the pulley bolts by turning them in a clockwise direction. Check the tension on your drive belt to ensure that it is operating smoothly. Adjust the tension appropriately by turning the pulley belts slightly counterclockwise to loosen it slightly or clockwise to tighten it up.
Use the Phillips head screwdriver to replace the screws on the elliptical machine cover.