Last Updated on November 4, 2021 by Jeff
If your treadmill operates just fine when it’s on its own, but it comes to a halt once there’s a load; then you have what we call a sticking treadmill. Even the best rated home treadmills can do this if it’s not properly set up, used, maintained, and adjusted.
Don’t worry too much, though. It’s usually an easy fix, and most can do it on their own at home. Only some cases require professional intervention or the need for replacing treadmill parts.
Causes of Stopping Under Load
Improper Use, Maintenance, and Adjustments
Poor maintenance and not adhering to usage instructions may cause your treadmill to malfunction. Here are some possible causes:
Ignoring the Weight Recommendations 
This is a simple but important one. Each treadmill manufacturer sets a maximum weight that the machine can tolerate. For example, the proform pro 2000 treadmill has a maximum weight-holding capacity of 375 pounds. If your weight exceeds this number, then the motor may fail to provide the power needed to move the running belt.
Lack of Lubrication
The most simple and most common cause of this problem is the lack of lubrication. It’s imperative to lubricate all the parts involved in the treadmill’s movement, including the running belt, drive belt, and deck.
Lubricants decrease friction between the running belt and the deck, allowing them to glide onto each other without interference. When there’s no lubricant, the belt and deck start to get worn down due to the high friction until they eventually can’t be used anymore.
Most treadmills should be lubricated about once or twice a year. Nordictrack, Proform, and Weslo treadmills are some brands that pre-lubricate the walking belt and require no further lubrication unless specified.
Too Tight of a Belt 
Sometimes the people over tighten the running and motor belts as they tend to stretch over time. While too loose a belt will lead to it slipping and slowing down, over-tightening also causes more harm than good.
The tighter the belts, the harder the motor has to work to compensate for the extra strain. This causes an overload on the motor, and the rollers’ bearings get worn down very fast, resulting in the treadmill becoming unable to move when you step on it.
For the treadmill to move well, proper tension between the front and back rollers must be present with a reasonable amount of friction. A way to check if you have the correct level of tension on the walking belt is by placing your hand under the belt and lifting it about 3 inches. The motor belt’s tension is considered suitable if you can rotate it about 90 degrees from its original position.
Improperly Positioned Back Roller 
Usually, the loss of proper tension is due to the walking belt stretching with time. Sometimes, however, the movement of the back roller is responsible for this.
You can easily correct its position by adjusting the bolts of the back roller. Rotate the right and left bolts equally about a quarter of a turn and check if you’ve achieved the correct tension level. Gradually keep turning and checking until your treadmill can move with you on it.
Maybe you want to find out about treadmill size and dimensions, then consider checking our blog – Treadmill Dimensions.
Damaged Treadmill Parts
Walking Belt and Deck 
If the walking belt still stops after adequately adjusting the tightness, then your deck or running belt is likely worn out and needs replacement. When there is excessive wear and tear, too much friction is created, and proper tension can’t be maintained.
Each treadmill has a troubleshooting section to check for the condition of the dack and running belt. Another way to check the belt is to see if it takes you less than 2-3 steps when you suddenly stop your treadmill at its lowest incline going at a speed of 3 Mph speed. If so, that means the friction and resistance are way too high, and the belt or deck is worn out.
Motor Brushes
With usage, the motor brushes responsible for conducting and transferring electricity are eroded and become shorter. This decreases the torque and power provided by the motor, which leads to your treadmill stopping with any extra load, aka you.
If your motor slows down when you try to impede the movement of its flywheel with an object, then it needs new brushes. Don’t risk any of your body parts in this process, and take care to apply the object in the same direction of the flywheel’s rotation to prevent any injuries.
Motor Demagnetization 
A motor rotates when its electromagnetic field is attracted to that of another magnet. If this magnet loses its polarity, the motor won’t work as it should. If you can slide out your motor core outside of its housing without feeling any resistance, then this motor is no longer any good.
Controller
If the controller isn’t supplying your motor with enough power, then your treadmill can stop, sometimes when you’re not even on it. However, this is very uncommon, and you should only consider it once you’ve eliminated all the other causes.
In Conclusion
There are many reasons your treadmill stops when you get on it, from improper usage and maintenance to worn out and damaged machine parts. Go through the most probable of causes one by one till you find what’s causing the problem.
And if you’re looking to buy a new treadmill, we made sure to include the maximum user weight in our treadmill reviews, like the Nautilus treadmill reviews and the NordicTrack 1750 reviews so that you can avoid any inappropriate loading problems.