Is your treadmill making knocking sounds while you run or walk on it? In such cases, it is essential to find the cause of the noise in order to preserve the treadmill and ensure it lasts you a long time.
From running deck issues to loose screws, we’ll list all the possible causes behind your issue. Plus, we’ll also give you some tips on how to fix the problem completely. Follow along!

1. Misaligned Belt Tracking
Usually, a treadmill makes knocking noises because its running belt is misaligned. In other words, the belt isn’t centered properly, causing the deck to put too much pressure on one of the rollers. Since this pressure isn’t distributed evenly, the belt makes a knocking (or thumping) noise when you take a step.
This particular issue often occurs with new treadmills, as most people don’t have the experience of setting one up properly. However, the problem is also quite easy to solve.
If you notice that the belt isn’t even, just take out an Allen wrench and turn the roller screws until the belt centers. In case the belt is too far left, you should turn the left screw, and if it’s leaning right, adjust the right one.
2. Uneven Surface Area
For a treadmill to be quiet and run smoothly, you have to place it on a completely leveled surface. If you put it on a fluffy carpet or an uneven floor, it will make knocking or grinding noises due to uneven weight distribution.
Luckily, most newer treadmill models come with adjustable legs. So, you can make one of them higher than the others to achieve perfect alignment if the floor itself is the issue.
And if you have a carpet, it would be best to just remove it and place a treadmill mat beneath your machine instead. Besides reducing knocking sounds, you’ll make your treadmill quieter in general, ensuring you can use it whenever you want without bothering anyone in your close vicinity.
3. Lack of Oiling/Lubrication
As you might already know, you should lubricate a treadmill regularly in order to increase its lifespan. If you don’t do it, the friction between the running deck and the treadmill belt will lead to less-than-smooth usage. With time, this issue can cause serious damage, including a malfunctioning motor.
In addition, a lack of lubrication can also cause grinding, thumping, and knocking sounds. The noise will be especially prominent when you’re running and increase as you pick up speed.
The solution to this problem is quite simple — you just have to get your hands on some treadmill oil and treat your machine at least once a month. And if you use it for more than 10 hours a week, it’s smart to oil it even more often, at least two or three times a month.
As for choosing the right lubricant, it all depends on the treadmill you own. Its maintenance instruction manual should contain all the necessary info for the particular model, including what lubricants you should and shouldn’t use.
Generally speaking, though, most models on the market are compatible with silicone lubricants. You can buy them in tubes and sprays depending on your preferences, and they are suitable for just about any budget.

4. Loose Pivot Points
Pivot points on a treadmill are spots where bolts or screws hold the machine together and connect its various parts. With time and excessive use, these points can loosen, causing the treadmill to knock, thump, and squeal as you use it.
The best way to solve this issue is to do regular maintenance on the pivot points. That is to say, you should check on all bolts and screws regularly and tighten them whenever you notice any signs of looseness.
By doing so, you will make sure the treadmill doesn’t break down from regular use. Moreover, it will remain quiet.
5. Faulty Rollers
Every treadmill has two rollers: one in the front, and the other at the back of the machine. When you turn it on, these rollers allow you to run or walk by continuously moving the rolling deck.
Sometimes, these rollers can break or become damaged. It usually happens to older treadmills that have been in use for years, and it manifests in several ways. For one, the deck might get stuck or be unable to roll properly at the speed you choose. Moreover, the machine may make thumping and knocking sounds.
If you have ruled out every other possible cause for knocking sounds and your treadmill is older than 5 years, it is safe to assume the rollers are faulty. So, your next step should be to check them.
To access the front roller, you will have to unscrew the motor hood. On the other hand, you can get to the back roller by removing the caps at the far end of the treadmill.
If you notice obvious signs of damage and wear, it is wise to replace the faulty roller entirely. That is the best option in the long run, as you’ll increase your treadmill’s lifespan by quite a few years.
Now, you should be careful when ordering new rollers. Namely, every treadmill type requires a unique set of rollers. Thus, getting the wrong ones will be a waste of both time and money.
So, before you order anything, check the rollers you have or look at the treadmill specification for the exact model. Alternatively, contact the manufacturer and ask for help. Once you have the exact model, you can go ahead and purchase them. Then, just follow the steps in your treadmill’s instruction manual to set everything up.
6. A Defective Incline Motor
Does the knocking noise occur when you try to set up a certain incline on your treadmill? In that case, you are probably dealing with a defective incline motor. It might be jammed or otherwise damaged, causing it to produce irregular and loud noises.
Whatever the issue, you should access the motor and inspect it. If it’s simply jammed, you’ll likely be able to fix it on your own by cleaning it. But if the issue is more serious, it is best to take it to a professional.
Depending on the cause, there are several potential fixes for a faulty motor. If the damage is not too severe, the mechanic will be able to fix it. Plus, the entire ordeal won’t be too costly.
However, if the damage is serious, you might have to replace the motor altogether. In the event of that, think of what’s more affordable and suits your budget better: replacing the motor or buying a new treadmill.
Final Thoughts
If your treadmill is making knocking noises, it’s crucial to find the cause. From an uneven surface area to problems with the running deck and incline motor, there are many potential issues that could be behind the sounds.
If you aren’t well-versed in treadmills, it might be best to contact the manufacturer directly. Most companies have customer support teams that are happy to assist with any issues you might be having. By getting in touch with them, you’ll do what’s best for your treadmill and ensure you actually get to the bottom of the annoying noise.
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