After continuous long-term use, the belt of a NordicTrack treadmill can lose tension. A belt that's too loose raises the risk of damage to the belt or the machine itself. Check the belt once a week. If the belt can be lifted more than 5 inches off the platform, then it needs to be tightened. It takes only a few minutes to tighten the belt on a NordicTrack treadmill, but doing so can greatly prolong the life of your machine.
Two-Adjustment Bolt Style
Look at the rear roller of the treadmill to determine whether it is a two-adjustment bolt style. If there is a head that takes an Allen wrench, it is a two-adjustment bolt style. (If not, skip to the next section) This style of treadmill requires you to adjust two different bolts.
Unplug the treadmill and remove the safety key to ensure the treadmill will not accidentally be turned on.
Insert an Allen wrench into the bolt on one side of the rear roller. Turn it clockwise one quarter-turn to tighten it. Locate the bolt on the other side of the rear roller and do the same.
Pull up on both sides of the belt to check the height. The belt should come up 3 to 4 inches from the platform. Both sides of the belt should be at an equal height.
Tighten or loosen the bolts until the belt is at the proper tension. To loosen the belt, just turn the bolts counter-clockwise.
One-adjustment Bolt Style
Look at the bolt on the rear right roller. If it has a hex head and a nut located at the end, then you have a one-adjustment bolt style. This style requires you to adjust only one bolt.
Unplug the treadmill. Remove the safety key if the treadmill has one.
Put a wrench on the nut at the end of the bolt to hold it in place. Place a second wrench on the head of the bolt. Turn the bolt clockwise a half-turn to tighten the belt.
Check the height of the belt to make sure it comes 3 to 4 inches up from the platform. Tighten the bolt further if necessary. If it needs to be loosened, turn the bolt counter-clockwise.