Treadmill Belt is Slipping? – 5 Reasons & How to Fix It

I love my treadmill. Like other runners, I use it when the weather is horrendous or I want to mix up my training.

It may happen to treadmills of all sizes and shapes that the treadmill belt starts to slip.

There are a variety of reasons why the treadmill belt might slip, and there are several methods to diagnose and address it, depending on its true cause. I share the five common reasons and how to fix them below.

Side note: About 60% of the time all your treadmill needs is some lubrication, but other times the issue is more severe. Providing routine maintenance to your treadmill will keep it working in optimal performance.

Let's dive into the five possible reasons that your treadmill belt is slipping:

  1. Treadmill Needs Lubrication

  2. Belt is Too Loose or Tight

  3. Drive Belt Might Be Loose

  4. Front Roller Pulley May Have Lost its Grip

  5. Belt Needs Replacing

We’ll cover possible causes and fixes in this article. 

Treadmill Belt is Slipping - 5 Reasons & How to Fix It

Why is a Treadmill Belt Slipping Dangerous?

The treadmill belt slipping to one side when you're running is a typical issue. This may be really scary.

Slipping is when the belt moves to one side beneath your feet while you're using the treadmill. The belt should stay in the middle of the deck rather than moving to one side or another. There should be no side-to-side movement.

When you fall off a treadmill that is moving, you run the danger of being seriously injured since the treadmill will continue to move for a brief period (even if you use the safety tether).

1. Treadmill Needs Lubrication

Every treadmill, even the most affordable to the high-end, needs to have a well-lubricated running deck to perform optimally. If the deck isn't lubricated, it might develop problems such as slipping and sticking.

The belt typically travels over from the treadmill deck over a set of rollers, and in order for the treadmill to run smoothly, there must be less friction between the belt, deck, and rollers.

The belt, deck, and rollers may wear out much quicker than usual due to friction between them. It's also very dangerous since sticking and slipping can result in missed steps and falls.

To reduce friction, lubricate your treadmill belt on a regular basis. To get an idea of how often you'll need to oil it, consult your user guide, as it varies by brand and model.

It's also important to research which lubricants are suggested. In the event you choose something else (like WD40), it's possible that your treadmill will be damaged.

Silicone-based lubricants are the most popular choice since they don't evaporate once used. Oil-based lubricants are not suggested because they can harm rubber components. Make sure to follow your owner's manual so that you don't over-lubricate.

Remember to wear gloves and make sure to follow the instructions carefully.

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What if I have A No-Maintenace Treadmill?

There are treadmills advertised as "no maintenance" that create the impression that you won't have to maintain the treadmill after purchase. This is simply a marketing tactic, so if you believe you won't have to care for the machine, belt slippage resulting in the need for lubricant will be your first issue.

2. Treadmill Belt Needs To Be Tightened or is Too Tight

When the belt isn't tightened enough, it might slip to one side while you're running due to the extra length. To much belt tension is not good for the treadmill.

Here's how to know:

With the treadmill turned off, pull your hand under the treadmill belt's rear end and raise it up. If it lifts more than 2 or 3 inches, then the belt is too loose and needs to be tightened.

When tightening the belt, be sure to follow the directions in your owner's handbook carefully. To prevent overtightening, tighten it gradually. It's about right when you can slide your hand under it and it lifts about 2 inches.

If you over-tighten the belt, the treadmill must work harder to get it moving. It might put a strain on the motor and cause it to stop working. This would be really bad so take your time tightening it.

One quick tip that I didn't notice in manuals - If you are tightening the belt on your own, remember to align it back in the center before making your adjustments.

3. Drive Belt Might Be Loose

Belt slippage will be inevitable if the drive belt between the motor and the front roller is slipping. If you step on the treadmill and its belt stops running but the motor is still running, then you should check out the front roller.

If the roller and the pulley also stops, then this is a clear indication that the drive belt is worn out.

In other words, since it will always be loose, no matter what you do the belt will continue to slip from time to time. The answer here is not to try and tighten it because that might result in overheating the motor if done too firmly.

The ideal solution is to change the drive belt, which will eliminate any additional stress on the motor.

Alternatively, you may try using a treadmill belt dressing spray, which you can purchase as an optional add-on from the treadmill shop for a short-term fix.

Check your owner's handbook before changing the drive belt that is located within the motor's hood cover, as some manufacturers advise that the hood cover should not be removed unless specifically instructed to do so by a reputable service shop.

If this process is not suggested by the manufacturer, it will typically void the warranty.

The treadmill deck's belt is not the same as the deck's drive belt. The drive belt, which connects the motor to the first roller beneath the deck, travels between these two components. Because it transmits power from the motor to the deck, this belt must function properly.

The belt may sometimes slip and cease operating while the motor keeps running. This suggests that the front roller, which is an important part of this device's function, may need some lubrication or adjustment.

It's possible that the roller and pulley that propels it will break down. This is an easy indication that the drive belt should be replaced. Even if the deck belt continues to operate, you'll notice it slipping and shaking.

You could try using a belt dressing, which is similar to a lubricant, on the drive belt. However, it's safer to just change this belt since too much tightening or improperly tightening it may harm the machine's pricey components.

4. Pulley on the Front Roller Lost It's Grip 

The treadmill belt may sometimes slip off the front roller because it has actually slipped off of it. The driving roller on a treadmill is the front roller, and if it becomes misaligned, the whole belt can come to a halt.

When the running belt stops, the drive belt and pulley continue to run. To restore normal operation, realign the pulley and roller tube beneath the belt. The simplest method to do so is to apply a strip of colored tape from the pulley to the roller in a straight line.

Turn on the treadmill and wait for the running belt to slip again. When it happens, switch it off and inspect the tape. If your roller and pulley are misaligned, this is a sign that your roller belt has come unglued. If not, then you'll need to seek an additional reason.

Sometimes, all that is required is for the pulley to be tightened. It may also need to be replaced on other occasions. You may inspect it and determine which appears most likely, in which case it's a good idea to hire an expert.

5. Time To Change The Belt

The treadmill belt may be slipping because it's had a lot of feet pounding on it and has just gotten old. It does occur, particularly if you purchased your device second-hand, use it frequently, or have numerous people in the household who uses it.

If lubricating the slipping treadmill belt does not help, or makes the problem worse, then you'll need to replace the entire worn out belt.

Performing this type of repair, if not authorized by the manufacturer, is usually considered voiding the warranty.

Check your owner's handbook because some companies advise that the hood cover should not be removed unless advised to do so by a qualified service center. If you don't follow these steps, your watch will most certainly need an overhaul.


A slipping treadmill's belt has the potential to cause serious harm, and you can't put a price on safety. It's preferable to spend some time investigating the problem and then investing some time and money into fixing it than to ignore it and end up tumbling later.

Treadmills can be dangerous, so be careful about replacing parts on your treadmill if it is covered by the warranty. There's a lot of delicate technology in some of the smallest to the largest treadmills. Some businesses won't be helpful if something goes wrong.

Hi, Jeremy Here, 

I am the the guy behind Train for a 5K. On this site, I share everything that learned along my running journey. The content I create is the running training I wish I had before we started this journeyAbout Me.

Last update on 2022-09-26 / Affiliate links / Images from Amazon Product Advertising API