How to Tighten a Treadmill Belt?

Share on facebook
Share on pinterest
Share on print
Share on email

You have invested in a treadmill to use in the comfort of your own home. Along with your purchase, and the ease of working out when you want, comes 'responsibility'. 

Maintenance of your machine is essential to prolong its life and protect your investment. When your treadmill is working as it should, you can be confident in the fact that your workout will be safe and effective.

One aspect of maintaining your machine is ensuring that the tension on the treadmill belt is correct. It’s therefore important that you know how to tighten a treadmill belt.

Time to look at why a treadmill belt might need tightening, how to recognize it and how to do it.

What is the Tread Belt?

The treadmill belt is the part of the machine which you walk or run on. Driven by a motor and drive belt, it wraps around a roller at the front and back, and covers the walking deck of the machine.

It rotates when you turn the machine on and is usually made of PVC, backed with a cotton polyester blend or a polyurethane.

What Indicates The Belt Needs Tightening?

There are indications which can alert you to the fact that your treadmill belt needs tightening.

You might feel the belt slipping or sticking when you are walking or running on the machine. This can compromise your safety and puts you at risk of injuring a muscle or joint, or falling over.

You might notice that the belt works fine when you are using it, but when a heavier family member gets on, it begins to slip. This is a warning sign that the treadmill belt tension is not tight enough.

Another indication is a sluggishness or slowness in the belt when you are walking on it. 

You may find that the belt drifts more towards one side than the other. This Is indicated by a wider gap between the belt and one side of the machine. 

What Causes Your Belt to Slip?

One factor to consider if your treadmill belt is slipping, is lubrication. Too much friction will cause the belt to stick as it can’t move freely across the running board. It’s easy to check if this is the fault.

Slip your hand underneath the treadmill belt and run your fingers along the bed of the machine. When you remove your hand, your fingers should feel slippery. If they are dry, then lubrication could be the issue.

Lubricating your treadmill belt is straightforward. Follow your manufacturer’s instructions and recommendations for lubricants. 

A loose treadmill belt will also be likely to slip or stick. Checking whether a treadmill belt is loose is an easy task. You can usually lift a treadmill belt away from the running board, but how much is the correct amount? 

When you lift the belt, there should be about a 3-inch clearance when the belt is at the right tension. If it lifts more than 3 or 4 inches, then the belt is loose. Less than 3 inches and the belt is likely too tight.

Inefficient drive

Another reason the belt could be slipping is a worn or inefficient drive belt. The drive belt connects the motor of the machine to the front roller. It is responsible for turning the roller, which then allows the treadmill belt to rotate. 

If the belt is worn or slack, the machine doesn’t work efficiently and the treadmill belt tension is not held correctly. This means the belt needs to be tightened or replaced. 

As with any maintenance on your machine, make sure you follow the manufacturer's recommendations. Failure to do so could cancel the warranty.

How to Tighten the Tread Belt?

Once you have established that your treadmill belt is loose, you will need to tighten it.

The majority of treadmills have two bolts located on the right and left of the machine at the rear. They are on either side of the back roller.

These bolts can be adjusted using an Allen wrench. Your machine might have been supplied with one which fits these bolts.

  • Turn off your machine and unplug it from the power supply.
  • Insert the Allen wrench and turn each bolt a quarter turn clockwise. It’s important to do these adjustments equally on each side, one turn at a time, to ensure you don’t over-tighten the belt.
  • Check the clearance of your belt from the running deck by lifting it, checking that it is at about 3 inches.
  • If you still have too much clearance, keep adjusting in quarter turns until it is correct.

Another way you can check is to slide your hand under the belt and push it towards the middle of the running deck. You should find your fingertips just reach the middle if the tension is correct. Less than middle is too tight, and more than the middle is too loose.

After each adjustment, as well as checking the height the belt rises from the deck, turn your machine on to about 3-4 mph and walk on it. If it is still slipping, continue adjusting until it stops.

This YouTube video shows you how to tighten your treadmill belt:

It is crucial that you don’t over-tighten your treadmill belt. A belt that is too tight puts a strain on the motor and can also cause the seams which join it together to separate. Replacing either the belt or motor can be costly.

Loosening the treadmill belt is the reverse of tightening it. Use the Allen wrench and adjust in quarter turns on each side, counter-clockwise.

Another thing you might notice when tightening the treadmill belt is that is begins to run off center. The process to correct this uses the same method of adjustment on the rear roller. The difference is this time you only adjust one bolt.

If the belt has a gap on the left side near the roller then you use the right-hand bolt to adjust it, and vice versa.  

Again, only adjust a quarter turn at a time. Then check by running the machine at 1 mph, without walking on it, in between adjustments.


We have looked at why your treadmill belt might need to be tightened and the signs that warn you if this needs to be done.  We have also provided you with easy steps to follow to carry out this maintenance.

Please make sure you unplug your machine from the power whenever you do any maintenance work on it. 

Always check the manufacturer's instructions for your particular machine. If you are unsure about what you are doing, or think there might be a bigger problem, contact an expert for advice.

If you have any treadmill tips or useful comments - or if you have a question for us - we are always happy to hear from you! 

Share on facebook
Share on pinterest
Share on print
Share on email

Leave a Comment