What Causes A Drive Belt To Break On A Zero Turn Mower?

A drive belt is an integral part of your zero-turn mower. It helps to power the blades and allows the mower to move in a forward direction. However, if this belt breaks, it can cause many problems for your mower – including rendering it useless. So, what causes it to break, and what can you do about it? Well, let’s take a look at what you need to know.

What Causes A Drive Belt To Break On A Zero Turn Mower?

One of the most common problems in zero-turn mowers is the drive belt breaking. Because these mowers run on pulley systems, any minor damage, too many clippings, no belt guard, etc., can cause the drive belt to break. Not only that, but inappropriate use and low maintenance may also cause it to need replacement faster.

How Do Drive Belts on Zero Turn Mowers Work?

Like lawn tractors, zero-turn mowers have drive belts too. However, zero-turn mowers run on pulley systems instead of the conventional transmission from the engine shaft to the input shaft.

The way they work, the drive belt receives its power from the electric clutch, then runs the pulleys. The power is then transferred to the blades, which start working.

Although the way zero-turn mowers work make them faster cutters than lawn tractors, it also means they can get broken faster. Any minor scratch or damage to a pulley bearing can cause the belt to stop working or get cracked.

4 Reasons Drive Belts Break On Zero Turns

There are multiple reasons why drive belts break. Unfortunately, a broken drive belt is a common problem among zero-turn mowers owners. Here are the most popular reasons.

Too Many Clippings

When the grass clippings accumulate on the mower’s deck without cleaning them, they eventually slip and reach the pulleys. When they’re too many, they may compromise the pulley’s movements, ultimately putting enough pressure on the drive belt to break it.

If the clippings are wet, it’ll be even worse because they’ll create large clumps.

To avoid this, the easiest way is to clean the mower’s deck after each use. It’s better for all the machine’s parts to do this to prevent an unnecessary accumulation.

Incorrectly Aligned Pulleys

If the pulleys aren’t correctly aligned, the whole system won’t run properly. There’s a chance the belt will break as a result.

The same can happen if there are sharp edges or cracks on the pulleys.

Generally, it’s better to check the pulleys now and then to ensure they’re running smoothly. This is because their state directly affects your mower’s drive belt.

No Belt Guard

A belt guard is a piece that goes around the pulley. Some people remove it when they replace the belt because it makes the process a lot harder. It’s a bit challenging to take out, but it protects the belt, so it’s essential to keep it.

When there’s no belt guard, the belt may be thrown off when you try to use the mower.

Worn Out Pulleys and Bearings

If you’ve been using the mower for a long time without maintaining or replacing the pulleys, there’s a chance they’re worn out. If that’s the case, they may cause the belt to break because they’ll likely have some sharp parts.

Pulleys also sometimes fail to spin freely when the bearings are worn out. 

Likewise, this will cause the belt to break or stop working altogether.

Try to constantly watch your pulleys and bearings for signs of wearing out. It’s always better to replace them before dealing with a broken belt.

Signs That Your Mower’s Drive Belt Is About to Break

If you lookout for a couple of signs, you’ll know that your belt is about to break. It’s better to realize the issue early on to prevent it from repeating.

Here are a few signs that your belt needs maintenance or replacement.

  • If the belt is getting worn out and showing rough areas, it’ll likely break soon. The belt’s surface should be entirely smooth without noticeable roughness. Seeing a rough patch is your cue to fix the belt.
  • If the belt’s sidewall is damaged, it won’t take long to follow its lead. If you take the belt’s cover off, you’ll see the sidewall in contact with the pulleys. It sometimes gets damaged or burnt, and that’s your cue to replace it to prevent the belt from breaking.
  • If there are cracks on the belt’s surface, it won’t take long to get entirely damaged. Try to check the belt every once in a while, and if you notice any cracks, work on fixing them before they cause the belt to break altogether.

How to Maintain Your Zero Turn Mower and Its Drive Belt?

To use your zero turn mower to the fullest, you need to know how to maintain it properly. The mower will keep servicing you for several years if you manage to do so. Here are some essential tips.

Clean the Deck

All of the mower’s clippings end up on the deck, including twigs, dirt, and all kinds of debris. If you don’t clean the deck often, you’re in for many problems. If the dirt builds up on the deck, it’ll eventually get to the pulleys and stop the system from working correctly. As a result, the belt will wear out faster than it should.

If you frequently mow wet grass, the clippings will be even worse because they’ll have a corrosive effect on your mower. In addition, its parts may rust if you don’t clean the deck quickly enough.

Clean the Air Filter Constantly

When the air filter gets clogged, it can directly affect your mower’s performance because the fuel will start burning less efficiently than it should. So, you need to check the air filter regularly. You’ll find it full of all kinds of debris, especially if you don’t clean it often. 

Store Your Mower Somewhere Safe

If it’s the end of the season, you should store your zero turn mower somewhere safe. You don’t want to leave it outside because it becomes a risk of rusting. Plus, it’ll be exposed to rough weather conditions when it’s outside, especially if you live somewhere with a lot of weather turbulence.

Not to mention, some animals or mice may find the mower warm enough to sleep in, and you’ll have a hard time getting rid of them when the summer gets around.

Make sure to store your mower in a shed or a garage. If it has a protective storage cover, it’s better to cover it to keep its parts from rusting.

Sharpen the Blades

Leaving the blades to go dull won’t only cause your mower’s engine to work harder, but it’ll also tear the grass instead of cutting it sharply. The torn grass will cake on the deck, eventually getting wedged between the pulleys and bearings. In turn, this will cause the belt to start cracking and eventually break.

Make sure to sharpen your blades regularly, and check the manufacturer’s instructions for sharpening them.

Pump the Tires

The tires don’t have much to do with the drive belt, but leaving them deflated will cause your mower’s life expectancy to shorten. Plus, if only one tire is deflated, it’ll cause the deck to work unevenly, and it’ll have a toll on all your mower’s parts.

Regularly check the tire’s pressure to make sure the two are the same.


So, what causes a drive belt to break on a zero-turn mower?

Well, it mostly has to do with the pulleys. If they’re worn out, damaged, or have sharp edges, the belt will break sooner than usual. It may also happen when there are too many grass clippings on the deck. 

They eventually reach the pulleys and compromise their motion. This may cause the belt to wear out faster or break.

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