Do Lawn Mower Belts Stretch?

Having a great lawn mower is one thing but keeping it in good condition is something else. From sharpening its blades, and fixing broken belts and blades to ensuring it mows the grass neatly, there is a lot that you require for proper maintenance of your lawn care companion. Lawn mowers are complex machines that come with different interconnected parts.

To ensure a mower works efficiently, you want to ensure that all these components are in good shape. For example, for self-propelled mowers, a faulty belt system can lead to a series of hitches and glitches in your machine.

Take, for instance, you are busy on your regular mowing schedule when you hear a “slapping” sound coming from your belt deck. Checking on it, it turns out that your mower belt is loose and that is what is causing the sound. As much as you try to tighten it, the same thing keeps on repeating itself. This is most common on riding lawn mowers especially if you are a landscape contractor. So, do lawn mower belts stretch?

Do Lawn Mower Belts Stretch?

Yes, with time, a lawn mower belt can stretch. Due to regular operation, the belt is subject to wear and tear causing it to elongate over time. When a mower belt stretches more than it should, the drive belts in turn lose grip on the pulley system. 

When a lawn mower is in use, its belts are always under tension. Over time, the belt may stretch to a point that it has a very loose grip on the pulley. Most lawn mower belts are sold with the durability or hours of operation that they will last before elongating. In some cases, you can try adjusting the tightness of the belt – by putting some more tension on it.

Nevertheless, in other situations, you might need to replace it with a new one. When the lawn mower belts stretch, the efficiency of your machine takes a dip. So, if your mower belt is completely worn out, you must replace it with a new one immediately. Apart from elongating, your mower belt might break, which is more common.

When your lawn mower belt elongates more than enough, it starts to slip. In other words, the belt drives will not transmit enough power to the engine and in turn, the tires will not move efficiently. Besides, some mowers completely rely on the pulley system to work. So, when the belt elongates due to wear and tear, your lawn mower fails.

Also Read: Are Kohler Lawn Mower Engines Good?

How Do I Know if I Need a New Mower Belt?

Before you head over to the nearest mower store and purchase a new replacement belt for your machine, you need to be sure that an elongated belt is indeed the cause of problems in your mower. Well, look out for the following signs:

  • Unusual Slapping Noise Coming from Your Mower’s Deck

A strange slapping noise from the deck is probably the first sign that your belt is stretched. Besides, it can also be a high-pitched squeaking sound. However, even if you hear any unusual noise from the mower’s belt, it doesn’t necessarily mean that it is elongated. Sometimes, the belt can become a bit loose and all it needs is a little tightening.

  • The Belt Won’t Stay On The Pulleys

If you increase the tension on your belt and yet it keeps on slipping off the pulleys, then this is a clear sign that your belt is elongated. In this case, you will need to install a new belt on your lawn mower.

What Causes a Lawnmower Belt to Stretch?

Now that you know how to tell if a mower belt is stretched, you might probably be wondering if there is something you could have done to prevent the elongation. Well, there are a few reasons as to why your lawn mower belt stretches, they include:

  • Age of The Belt

This is far less common because a very old belt is more likely to break or crack rather than stretch. Nevertheless, we cannot rule out the fact that a belt loses some of its elasticity over time and thus stretches out.

  • General Wear And Tear

Remember that when using your lawn mower, the belt is always under tension. Particularly, if you are a landscaping contractor, there is no time taken off for your machine. Over time, your lawn mower belt will eventually lose its elasticity, becoming slightly longer.

  • Quality

Original Equipment Manufacturer (OEM) belts are costly but high quality and do not elongate easily. On the other hand, their aftermarket brands counterparts are cheap and more prone to stretching. It is hard to know the type of belt on your equipment unless you install it yourself.

Are Lawn Mower Belts Supposed to be Loose?

No, lawn mower belts are not supposed to be loose. On one hand, if the belt is too tight, it can break, crack or even damage the mower deck. On the other hand, if it’s loose, it may come off the pulley. 

Notably, the belt is responsible for transferring power from the engine to the tires of your mower, if it is too loose, then your machine will not move. Besides, a loose belt can come off the mower deck. This means that you won’t be able to operate your equipment or work on your turf.

Can V Belts Stretch?

A V-belt function links together the rotating shafts. As such, the V-belt must be flexible enough to stretch and expand to accommodate the rotating shafts. Besides, the stretching of the V-belts has its share of advantages, particularly when you need to replace them with a new belt. 

How often Should You Replace the Lawn Mower Belt?

There is no definite answer as to how often you should replace your lawn mower. However, depending on the type of lawn mower, the belt can last from 3 to 10 years before you need a replacement. A rule of thumb, the more you use your mower, the higher the chances of your belt stretching. Therefore, you should replace your mower belt immediately after you see the signs we discussed above.


Improving and maintaining the efficiency of your lawn mower is not a walk-on-the-run. However, this article details all the top-notch DIY care tips. What’s more, you can learn from the experts – lawn care equipment comes with a comprehensive user guide to back you all the way through. From guidelines on how to replace worn-out mower parts, to signs that indicate a bet stretch, you won’t miss any relevant information.

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Victoria Peterson

I am a passionate gardener who wants to help you create and maintain your dream yard. I know that it can be daunting to take on a project like this, but I am here to help. I have been gardening for years and have learned a lot along the way. I want to share my knowledge with you and help you create the perfect yard for your home.

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