How To Adjust a Treadmill Belt

At Home Gym Supply, one of the most common questions we get asked is how to adjust a treadmill belt. Whether it is to tighten, loosen or realign the belt if it isn't running in the centre.

So we decided to create a step-by-step guide to assist our readers and customers in adjusting their treadmill belts. Here's everything you need to know to ensure a smooth and safe treadmill experience.


What to Look For?

If you are unsure if the running belt needs adjusting, there are a few telltale signs to look for that will help you determine what adjustments you need to make.


Belt Alignment

When you look at the running belt, there should be an even gap on either side showing that the belt is aligned in the centre of the running deck.

If it is sitting to one side, then the belt could stretch unevenly or rub against the side of the treadmill causing damage to the treadmill.

Treadmill Belt Alignment

Some treadmills have the edges of the running belt covered, so you might need to remove the guards to see if it is aligned correctly.

If your treadmill is foldable, you can sometimes lift the deck up and quickly check underneath to see the rear roller and check the alignment.

 Related: Best Treadmills for Home

Treadmill Belt Slipping?

If you find that the treadmill belt is slipping/ skipping while the treadmill is running, then the belt is likely too tight or too loose causing the belt to slip and not rotate as it should.

Generally, if you lift the running belt in the middle of the deck, the belt should lift off the running deck between 2 to 3 inches. The tension can vary depending on the manufacturer but this measurement is normally the recommended amount.

Treadmill belt tension test

If you haven't lubricated the belt in a while, we recommend you see our guide on how to lubricate a treadmill belt as this could also help resolve this issue. 

If you have checked the belt's tension but find the treadmill is still slipping/ skipping, then it could be possible that the issue is with your drive belt which connects the motor to the roller.

For this issue, you will need to refer to the owner's manual as you should be able to adjust the motor position to increase the tension in the drive belt.


How To Tighten a Treadmill Belt

Belt Tension ScrewIf your running belt is too loose then you will need to follow these steps to tighten the treadmill belt:

1. Ensure the treadmill is turned off and disconnected from the power source.

2. Find the tension roller screws at the rear of the machine.

3. Tighten the screws on the left and right-hand side of the machine a quarter turn at a time to keep the tension even on the belt.

4. Check the running belt tension by lifting the belt in the centre of the running deck. You should be able to lift the running belt about 3 inches off the deck.


How to Loosen a Treadmill Belt

The steps to loosen a treadmill belt are just the reverse of how you tighten a belt. If you are unable to lift the belt off the running deck by 2 to 3 inches then you will need to loosen the belt by following these steps.

1. Turn off the treadmill and disconnect it from the power source.

2. Locate the tension roller screws at the rear of the machine.

3. Loosen the screws (normally turn the Allen key anti-clockwise) by a quarter turn at a time, alternating between the left and right screws. It is important to loosen the screws simultaneously to prevent the belt from becoming miss aligned and the tension even.

4. Check the running belt tension by lifting the running belt.

5. Repeat step 3 until the running belt can be lifted off the deck about 3 inches.


How to Align a Treadmill Belt

If your treadmill running belt isn't aligned in the centre of the running deck, you will need to adjust the tension screws to align correctly. You can align a treadmill belt by following these steps:

Idler Roller Tension Screw1. Turn off the treadmill and disconnect it from the power.

2. Check the belt to identify whether it is sitting on the left or right of the running deck. If the running belt is covered you might need to remove the running guards to see the belt's alignment.

3. Once you know which side the running belt is favouring, locate the tension screw on the same side of the treadmill and turn it a quarter turn.

For example, if the running belt is aligned to the left-hand side of the running deck, you will need to adjust the tension screw on the left-hand side so the roller pushes the running belt over to the right.

4. Manually rotate the treadmill belt a few turns so that the running belt can settle into its new alignment and check whether it is centred. If it is still sitting close to one side, then repeat step 3 until it is centre-aligned.

5. Once you are happy the belt is correctly aligned, check the running belt tension to see if it isn't too tight or loose. Lifting the running belt off the deck about 3 inches should be possible.

6. If the belt is too tight or loose, follow the instructions above to tighten or loosen the belt.

7. Now reconnect the power and turn on the treadmill then let it run at the lowest speed and check that it remains aligned in the center of the running deck.


Rounding Up

To ensure you stay safe while using your treadmill it is important to regularly check your running belt and makes adjustments when they are needed.

We hope you have found our guide useful and now have a better understanding of how to tighten, loosen, and align the treadmill belt correctly.

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Treadmill Benefits

Author's Photo

William Parrett

Will, co-founder of Home Gym Supply, launched the company in 2019 after 15-years in the fitness industry. His expertise stems not only from his professional background but also from his athletic pursuits. A former competitor in the World Beauty Fitness & Fashion (WBFF) and a competitive rugby player, Will has always been dedicated to health and fitness.