Your mower drive belt can last a long time. This makes it an effective tool to keep around for a long time. However, there is general wear and tear that can occur to the mower drive belt, and eventually, it will break if you do not replace it.  

Under ideal conditions, a mower drive belt will last between three to four years. If you use the mower quite a bit or if you do not take good care of the machine, it may wear out sooner. Wear and tear often makes it hard to keep the mower belt going for longer than four years.  

A lawn mower belt can last longer than four years when the mower is kept clean and it is inspected every year. 

Let’s take a closer look at how long a mower drive belt should last along with some of the ways you can tell the mower belt is wearing out and needs to be replaced.  

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Follow all safety instructions provided in your equipment operator’s manual prior to diagnosing, repairing, or operating.Consult a professional if you don’t have the skills, or knowledge or are not in the condition to perform the repair safely.

How Long Will My Mower Drive Belts Last? 

Your drive belts will be able to last between three to four years, depending on how much you use the lawnmower. There are several different types of belts responsible for: 

• Driving the wheels on a self-propelled mower 
• Driving the wheels on a garden tractor 
• Driving the pumps on a commercial mower 
• Driving the deck turning the blades 
• Running the grass collection system 

All of these items rely on belts to drive them. 

This is an additional belt found on a riding mower or a self-propelled mower. It can wear out within four years in most cases and needs to be replaced within that time period. You must look for some of the common signs and symptoms to see whether this part needs to be replaced early or not.  

When Should I Replace My Mower Belt? 

Unless you notice some signs of the belt wearing out, you should replace the drive belt within four years after putting a new one on. Check the mower out if you purchased it used from someone to see if it is time to do a replacement on your own.  

The best way to tell whether a drive belt is worn or very worn and about to break on you is to do a visual inspection of the belt. Some big signs to look for include: 

• The belt is shiny with no ridges or bumps. This means the belt is worn and slipping inside the grooves of the pulley. 
• The belt has cracks or is torn on the edges. This happens right before it snaps.  
• The belt has lots of slack between the pulleys. It will not run efficiently when this happens.  
• The belt has more than ½” deflection in it indicating the belt may be riding too far into the pulley and therefore the pulley may be worn out also. 

These visual signs will tell you it is time to do some work on the drive belt to make sure that it is repaired quickly, and you can keep using your mower the right way.

Sometimes it is hard to know whether the belt is in bad shape, or those physical signs do not show up right away.  

When this happens, it is time for you to look for other signs that something is wrong with the drive belt. You may notice some squeaking or squealing noises when you turn on the mower. This means you need to turn it off and inspect the drive belt as soon as possible.  

Other signs that the drive belt is not working well and needs replaced includes: 

• The mower stops or has trouble stuttering.
• Lots of vibration throughout the mower.  
• The mower may not be running up to its normal pace. 
• The mower may not move right away until the belt gets warm. 
• The mower won’t go uphill very well. 
• You may smell the belt burning because it can’t move the heavy mower. 

Even if the belt still looks pretty good at this point, it is time to do some replacement to make sure it does not break on you while mowing. Check the tension springs as they can break or you may have a pulley with dirt, mud or debris stuck in it. 

When to Replace a Self-Propelled Mower Belt? 

A self-propelled mower is a great option because it can get the work done without you needing to do all the heavy pushing. You do need to be there to help steer the mower. To tell whether it is time to replace this belt, you should look for: 

• Squealing or loud sounds from the mower.  
• Suddenly needing more force to push the mower.  
• The mower is much slower than normal.  

When these symptoms start to happen, you should replace the drive belt as soon as possible. This will help keep it from snapping and protects your mower.  

When Should I Replace a Riding Lawn Mower Belt? 

Similar to what we discussed with the self-propelled lawn mower, you need to replace the belt when it stops working well. Some of the problems that you should look for with your riding lawn mower belt include: 

• It is hard to drive the mower compared to before.  
• The mower starts to feel like it is stuttering when you drive it. This is a sign the belt has slipped. 

When the belt starts to break often, it is a sign that something else is wrong with the mower and you may need to look into that more. Having too many grass clippings in the deck, or an oil leak could cause this problem for example.  

How Can I Replace a Lawn Mower Deck Belt? 

Replacing one of these belts does not need to be difficult, even if you do not have a lot of experience. Make sure that you have a few wrenches around and some free time to work on them.

We have provided instructions for a standard lawn mower where you don’t have to remove the deck. You may need to remove the deck on your model.

Now that cell phones have phones on them and they are readily accessible, it is a good idea to take photos of the belts and spring before you take anything apart.

We receive a lot of phone calls from customers asking about routing belts on a lawn mower. Having a picture will help you when you go to install the new belt. 

A standard lawn mower deck belt replacement looks like this: 

• Set the height of the mower as low as possible.  
• Take the covers off the mower deck.  
• Pull the old belt out. Do this by releasing the tension and pulling it out of the left spindle pulley. 
• Find the mower belt idler arm and then remove the hardware above it so you can reach the hook.  
• Remove the spring and then put the mower deck back in the highest position

From here, you will need to bring out that wrench to do a little work. Loosen the hardware that holds onto the idler so you can remove this part.

You will need to hold the bolt head under the deck to remove the nut. Always use some caution anytime you reach under the deck of the mower.  

With this nut out of the way, you can put the mower deck back to the lowest cutting position. Take all of the hardware that is on the retaining belt keeper and remove it. You should now be able to remove the belt off the clutch pulley, which is located under the engine.  

From here, we want to install the new belt in place. The other steps helped to take the old one off. The steps you can use to help with this include: 

• Put the belt against the rearmost idler pully. Reinstall your belt keeper. 
• Install the belt at the clutch pulley at the back of the unit.  
• Return the idler to its position and raise the mower deck to reinstall the idler assembly. Only finger tighten here.  
• Reach under the deck and hold the bolt head to help place and tighten the nut securely.  
• Lower the mower deck as low as possible.  

You can then reinstall the belt keeper into the idler arm and put the spring hook back in place. Check that the belt has the right tension at this point and that it is aligned well in all your pulleys in the mower. Reinstall all the parts on the top of the mower and you are good to go! 

Replacing Your Mower Transmission Drive Belt 

It is important to watch for your mower drive belt to make sure it can last a long time. When it fails, you may be stuck with a lot of work to help replace it.

By recognizing the signs above and taking care of the drive belt before it breaks, you can keep your mower protected and working well. It is recommended you take your mower to your local repair shop to have the transmission drive belt replaced.

If you bring your mower to your lawn mower repair dealership at the end of every mowing season for inspection, you can save a lot of time and potentially money on repairs. Many repair shops may run specials in the winter during their slower business season. 

Check to see if your dealership will guarantee their work the following spring season because you are bringing your mower in to be serviced during their slow times and prior to being able to use the mower for several months. 

More Information 

Read more about lawn mower belts with our articles: 

This is Why Your Belt Keeps Falling Off Your Lawn Mower

V Belts: What Are They? We’ve Got the Answer

How To Change A Belt On An MTD Lawn Mower