Sportscraft TX 4.9 treadmill manual - Exercise & Fitness

SOURCE: bogs down

Sounds like either the belt is loose or the belt/deck need to be lubed.
To tighten the belt, start by locating the two bolts that adjust the rear roller (one on each side of the unit in the back). Run the unit at about 3 mph. Tighten the bolts a 1/4 turn at a time. Make sure that what you do to one side, you MUST do to the other side or the belt will get off center. After you tighten it 1/4 turn, check the belt to see if it is still slipping. If it is then tighten the belt 1/4 turn again. Continue until the belt does not slip, but do not tighten the bolts more than 2 full turns.
To lube the treadmill, use silicone spray and spray between the belt and deck on both sides. I hope this helps. Let me know if you have any other problems.