Cub Cadet Belt Keeps Coming Off – Why And What To Do?

It is very frustrating to install your Cub Cadet mower belt only to have it come off. Want to know the causes of this problem and how to fix it? Well, we've sifted through the internet and gathered the answers to share with you.

The reason why your Cub Cadet belts keep coming off is any of the following, together with the ideal solutions:

  • Accumulated Dirt On The Belt - Clean Up
  • Damaged Pulleys - Replace
  • Deformed Belt Keeper - Straighten/Replace
  • Faulty Bearings - Replace
  • Inappropriate Belt - Install Appropriate Belt
  • Misalignment Of Belt - Align 
  • Rusted Belt - Clean Up
  • Shredded Belt - Replace & Adjust The Rubbed Spots
  • Split Plate/Bracket - Weld/Replace
  • Stretched Belt - Replace
  • Worn Out Belt - Replace

In this article, we'll discuss each cause of the belt coming off in detail, along with the solutions for each one. More information is ahead so that you could keep using your mower in cutting the grass effectively. 

Cub Cadet Belt Keeps Coming Off - Why And What To Do?

Cub cadet yellow tractor mower - Cub Cadet Belt Keeps Coming Off - Why And What To Do

You must set aside some time to examine all the parts that come into contact with your Cub Cadet belt closely if you want to figure out why a deck belt keeps coming off. 

At least one of them or the belt itself will have some form of issue. They don't just simply fall off without a cause. Follow the checklist until you identify the root of the problem. 

Closeup of lawn mower deck, drive belt, pulley, and grease zerk fitting. Lawn equipment maintenance and repair concept

Accumulated Dirt On The Belt - Clean Up

Stones and wood chips could get caught in the grooves or underneath your pulleys, and these materials might accumulate there. Your deck may have problems moving the tension pulley if it accumulates dirt. As a result, the belt of your Cub Cadet could come off, or worse, it may break due to anything as simple as packed dirt around the pulley. 

Quick Fix: After every use, you should clean your deck to preserve performance and prevent dirt buildup. The best way to clean up the underside deck of your Cub Cadet is by using the wash adapter. 

Click here to see this wash adapter on Amazon.

You only have to thread the wash adapter onto your water hose and stick it to the washout port of your lawn mower, engage the blade and then it will start cleaning everything else. This could prevent several potential problems that your Cub Cadet mower might experience.

To see how it works in reality, a video on YouTube is shown below.

Damaged Pulleys - Replace

The deck belt should rotate freely and level around each of the pulleys. These pulleys frequently do damage due to usage, and if they are no longer level during operation, the belt might slip off the pulley. 

You will need to completely remove the belt in order to check this, and then you should examine each pulley separately. The issue can arise if you find one that isn’t spin-level.

Quick Fix: With some force, you can attempt to bend them back into position using a hammer. The bracket often gets bent. In the worst case, you might have to replace the pulley.

Click here to see this pulley replacement on Amazon.

Deformed Belt Keeper - Straighten/Replace

These belt keepers are made to keep the belt in its proper position on the pulley. If any of these were too deformed or bent, the belt would have a hole to pass through. The deck belt frequently comes off when lowering and raising the deck when the belt keeper is out of shape.

Quick Fix: Examine each belt keeper to check if it has been bent out of shape and straighten those that are not in the proper position. However, take care not to position them too closely to the pulleys as this will prevent them from freely rotating.

Click here to see this belt keeper on Amazon.

Faulty Bearings - Replace

three faulty rotors from electric motors on a white background

The Cub Cadet belt might come off because of pulleys or spindle housing assembly have faulty bearings.  Examine each of your pulleys. Ensure that they are parallel to the deck and running flat. Also, seated farther away from the deck than the other.

Quick Fix: Your Cub Cadet may vibrate due to an issue with the spindle casing, which might also cause your belt to come off a pulley. 

Click here to see this spindle assembly on Amazon.

Wearing sturdy work gloves can help prevent cuts from sharp blades while you inspect your housing. To ensure safety, make sure the spark plug boots are taken off as well as the ignition key.

Rock the blade up and down by holding onto each side of it. Keep an ear out for any knocking noises. When rocking the blade, you are also feeling for any movement. 

You must disassemble the spindle housing and inspect it for a damaged bearing or other issues if you notice either of these signs of a damaged spindle housing. Replace the entire assembly if the spindle housing is sealed, but if it is not, rebuild it.

To see how to remove the spindle bearings, a video on YouTube is shown below.

Inappropriate Belt - Install Appropriate Belt

There are many different deck belt options available, and ordering online might be risky. It might be too big if you got the incorrect belt for your lawn mower model, which would explain why it keeps coming off. If this is the issue, it will usually be clear because you will begin experiencing this issue immediately after installing or replacing the belt.

Quick Fix: If you purchased the inappropriate belt, you must order the appropriate belt and fit it. Even though paying twice for belts is inconvenient, they will no longer come off.

Click here to see this replacement belt on Amazon.

Misalignment Of Belt - Align 

The alignment of the belt is essential to its operation. Your belt may come off if it is even slightly out of place.

Quick Fix: Simply move the belt a little to the proper position to immediately correct this.

Rusted Belt - Clean Up 

Cadet Riding Tractors on display

Rust can dry out the belt, which can make it difficult for your Cub Cadet mower to start. Also, it can cause the belt to move out of alignment.

Quick Fix: If you see this symptom, pull out the belt and clean it. Get a wire brush; it will assist you to get rid of the rust flakes. 

Click here to see this wire brush on Amazon.

Spraying a high-quality silicone lubricant on the metal is an excellent idea. And if cleaning can’t remove the accumulated rust on it then replace the belt.

Click here to see this silicone lubricant on Amazon.

Shredded Belt - Replace & Adjust The Rubbed Spots

Your belt rubbing against a belt keeper or a bracket on the deck may cause it to shred. Another possibility is that your belt is not properly positioned around the deck's structural elements. Check to make sure your belt is in the right position, and examine the deck for any spots where it might be rubbing.

Quick Fix: On your deck, a shiny piece of metal is a good place to look to see whether the belt is rubbing against it. You'll need to make an adjustment to the belt to stop rubbing once you identify what it is rubbing against. 

If the bracket that the belt is rubbing against has a bushing, you may need to replace the bushing or buy the entire bracket assembly.

Click here to see this bushing on Amazon.

Split Plate/Bracket - Weld/Replace

Most of the attention is focused on the belt itself, the pulleys, and the pulley keepers when your mower deck belt keeps coming off. These are the main suspects, so you should check them first. 

Look attentively at the pulley bracket and the plate it is attached to determine if there is anything wrong with them. When the mower is in operation, the extra "give" from these split parts might cause the pulley to shift and the belt to come loose.

Quick Fix: This problem would need the welding of a split plate and the replacement or repair of a bracket.

Click here to see this bracket replacement on Amazon.

Stretched Belt - Replace

Cub cadet yellow tractor mower

If your belt has been in use for a while and you can't see any obvious wear or damage, but it still looks in good condition, it might have stretched. 

If so, it might explain why your mower deck belt keeps coming off since it is now too large. The belt will eventually come off, even if it is just a little too big. The engine belt stretching is fairly normal over time. The belt will become looser as a result of the stress and warmth. 

Quick Fix: Since you cannot reverse the stretched lawn mower belt, your only choice is to get a replacement. To show you the proper way to replace the belt, a video on YouTube is shown below.

Worn Out Belt - Replace

This is the common issue on the Cub Cadet that you might hear a lot. The deck belt starts to fall off more and more as it ages. This is why the belt falls off because it gets thinner in these worn-out areas.

Quick Fix: Since it is not possible to repair these worn spots, your only option in this situation is to replace the deck belt. Always use an original equipment manufacturer (OEM) belt instead of a cheap aftermarket replacement because they frequently wear out very rapidly.


Cub Cadet riding lawn mower trademark and logo. Cub Cadet produces outdoor power equipment and services.

By performing these aforementioned repairs, you can quickly restore your Cub Cadet mower to working order and extend its lifespan without the need to hire a technician. 

If you find further issues, look for additional solutions by looking at the mower's manual. Take the mower to the closest service facility for prompt repair if the problem persists.

For more valuable mower topics, check out below.

Cub Cadet Blowing White Smoke – Why And What To Do?

10 Best Lawn Mowers For Wet Grass


One comment

  1. If your deck belt keeps jumping off on your Cub Cadet riding mower, take a look at the front belt guard located at the pulley mounted on the engine. If it is not within 1/8″ on both sides of the pulley, it is installed backwards. Remove it, turn it around and you will see what it will sit farther back onto the pulley and within 1/8″ on both sides and the belt will stop jumping.

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