How To Tighten And Adjust A Treadmill Belt Yourself

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Treadmills have a lot of components that require maintenance. The running belt is one of the biggest aspects that can cause issues if they aren’t properly taken care of and adjusted. The belt, after all, allows you to run at up to 12 mph on some treadmills.

Along with lubricating, from time to time, your treadmill’s belt might need to be tightened or adjusted. Here at TRG, we’re treadmill experts who are regularly tightening and adjusting treadmill belts. Our goal is to help you not only find the best treadmill for you but also help you maintain your treadmill.

Your treadmill’s belt takes the brunt of your workouts, you want to maintain it properly.

Adjusting And Tightening Your Treadmill Belt

Whether you’ve put hundreds of miles on your treadmill or are hopping on it for the first time, the belt might need to be adjusted. It isn’t often that we pull a treadmill out of a box that needs adjusting, but it happens.

More commonly, a regularly used and well-loved treadmill needs adjusting. What adjusts the belt is the rear roller that the belt moves around. Moving the roller back tightens the belt and moving it forward loosens it.

Here is how to adjust the roller and adjust and tighten your treadmill’s belt.

1. Assess if your belt needs to be tightened or adjusted to one side. If it needs tightening, you’ll adjust it on both sides of the deck. If it has pulled to one side, you’ll just need to adjust it on one side.

2. Turn off your treadmill or set the speed to 1 mph. (It can be adjusted while on or off. It’s safer to do while off).

3. If you are adjusting the belt to one side, go to the side of the belt that it is shifted over to. For tightening, you can start on either side.

4. With an Allen wrench (most treadmills come with one) locate the back of the deck behind each side rail. You’ll see a small hole on each side.

5. You’ll fit the Allen wrench in the hole on whichever side you’re adjusting first. If you’re adjusting the belt to one side, you’ll need to tighten the side that the belt has shifted to. You’ll then turn the wrench in the direction you want to move the belt to. For example, if the belt has shifted too far to the left, you’ll adjust it on the left side and move the wrench to the right (clockwise).

For tightening the belt, you’ll turn the wrench clockwise the same amount on both sides. I recommend doing so in small quarter turns with the wrench when adjusting the belt. Whenever you adjust the belt, keep track of how much you turn the wrench, that way you make sure to adjust both sides the same amount when tightening it.

6. If you have the treadmill off, you’ll turn it on and set it to 3 mph without anyone on the treadmill. If you have it on already, turn the speed up to 3 mph and watch the belt to see if it evens out (if it was shifted). If the belt needs more tightening, place your hand underneath the belt to assess how much slack there is with the treadmill off. You should only be able to lift the belt on the sides by 2-3 inches. Any more, the belt is too loose and any less than this, the belt is too tight.

You can check this by lifting the edge of the belt from the middle of the deck between the motor hood and the rear roller. You can also check this by slipping your hand under the belt. If you can reach the middle with some effort, the belt is good. If you can reach underneath to the other side, it needs tightening. If you can barely reach under the belt, it is too tight.

Signs Your Treadmill Belt Needs Adjusting

Here are some things to look out for that can indicate your treadmill’s belt needs adjusting.

The Belt Has Shifted To One Side

This is a pretty obvious sign. If you look at the belt from the rear of the treadmill and notice that it isn’t centered, this means that it needs adjusting. Another indication that the belt has shifted too far to one side is that it makes noise. You can sometimes hear a rubbing sound when the belt is off-center.

If you notice that one of the sides of the belt has started to fray or unravel, this could mean that the belt is off-center. I recommend checking your treadmill’s belt before it reaches this point. If the belt has started to fray on the sides, it needs replacing. A fraying belt is a sign that it is worn out, too.

It’s Too Loose

If you lift the treadmill’s belt on one side and you can lift it higher than 2-3 inches, this means that the belt is too loose. Another sign that the belt is too loose is that it slips or sticks. For example, the belt feels like it is slipping underneath you. This could be worse and more obvious when you incline the deck.

If the belt is sticking, it can feel like the belt is pausing for a moment when your feet land on it. A slipping or sticking belt doesn’t feel smooth and consistent like it should. This could be because the belt needs tightening or lubricating.

If the belt still sticks or slips after tightening, it might need to be lubricated. If all of this doesn’t work, you should check the drive belt that’s next to the motor. This is a small belt that moves the rollers to then move the running belt. The drive belt can be too loose and need to be tightened, rather than the running belt just needing to be tightened.

Learn more about how to fix a slipping belt, here.

It’s Too Tight

The easiest way to determine if your treadmill’s belt is too tight is by putting your hand underneath it. If you can’t reach the middle of the deck underneath, it is too tight. An over-tightened belt can lead to problems and damage the belt. If the belt starts to crease, this means that it is too tight and not lubricated enough. If the belt has creased, it will need to be replaced because this prevents it from smoothly gliding over the rollers.

A properly adjusted treadmill belt helps to ensure the treadmill runs as it should.

Bottom Line

It’s important to regularly inspect and maintain your treadmill to ensure that it runs properly and lasts. The belt is an important component, so we recommend checking it regularly to be sure that it hasn’t worn or shifted off-center. It’s also important to keep it lubricated and properly tightened.

We hope this helps you adjust and tighten your treadmill belt yourself. Be sure to check out our list of the best treadmills on the market, to find your perfect treadmill.