The drive belt is too loose. you need to tighten the belt that drives the front rolller, which drives the walking belt. depending on the type of treadmill there shoudl be a way you can do this by loosening the motor and adjusting that to tighten the belt. it could also be that the belt needs to be replaced and also could be the walking belt. you should try to tighten the walking belt first. that is at the end of the treadmill where you walk on it. there are two holes one on each side of the treadmill where teh belt goes back under the treadmill. there are allen key bolts that you need to tighten clockwise one turn then try the treadmill. if it doesnt tighten then turn another full turn. if not tight enough then it might be the drive belt. if you tighten the walking belt all the way then try to tighten the drive belt.
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The drive belt is too loose. you need to tighten the belt that drives the front rolller, which drives the walking belt. depending on the type of treadmill there shoudl be a way you can do this by loosening the motor and adjusting that to tighten the belt. it could also be that the belt needs to be replaced and also could be the walking belt. you should try to tighten the walking belt first. that is at the end of the treadmill where you walk on it. there are two holes one on each side of the treadmill where teh belt goes back under the treadmill. there are allen key bolts that you need to tighten clockwise one turn then try the treadmill. if it doesnt tighten then turn another full turn. if not tight enough then it might be the drive belt. if you tighten the walking belt all the way then try to tighten the drive belt.