What Causes a Riding Lawn Mower to Cut Uneven?

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Sometimes people find that the riding lawn mower cuts the grass unevenly. This can be disturbing, as it makes your job much more difficult. This is usually a sign that something is amiss, and you can go through a checklist to determine what is causing it. Once you find the answer, it is pretty simple to fix the problem and get back to cutting your grass.

The most common causes for a riding lawn mower to cut uneven are:

  1. Mowing too fast
  2. Incorrect tire pressure
  3. Improper mower deck level
  4. Uneven Ground
  5. Turning inappropriately
  6. Faulty spindles
  7. Dull/bent mower blades

Let’s take a closer look at some of these common issues that lead your riding lawn mower to cut the grass unevenly.

Mowing Speed

You may not realize that the speed of your riding lawn mower will affect how it cuts the grass. If you accelerate too quickly or go too fast, it can tear grass blades rather than cutting them, which makes the lawn look uneven. In addition, these torn grass tips can turn brown. Another issue with speed is that driving fast can make your mower bounce on the surface, which will leave uncut patches followed by patches that are almost bald.

The way to fix this problem is to slow down so that your lawn mower blades are able to cut the grass. However, make sure that you don’t move too slowly or you can end up with clogs in your mower. The ideal pace is a brisk pace that is not too fast or too slow. The best way to find your ideal pace is to practice and see which produces the best results.

Tire Pressure

 Another factor that can impact how evenly your riding mower cuts is the tire pressure. Most people overlook this unless they have a flat tire, but low tire pressure can change your steering and cause the mower deck to sit unevenly on the surface. You should make sure that your mower is parked on a flat surface before you check the tire pressure. Let the engine cool because the tires warm up when you use the mower. You should find the manufacturer’s recommendation for the ideal PSI for your mower in the manual. You can also look it up online.

When you add air to the tires, make sure that you don’t add more air than the recommended PSI, or your tire might fail altogether. You can also check your tires for wear and tear to make sure that they haven’t rotted. It is important to make sure that your tires are in good shape, just as you would for your car.

Mower Deck Level

It is important to make sure that your mower deck is level when you are cutting grass. If you notice that you have alternating paths of grass that have different blade lengths, you might have a tilted mower deck.

If you discover that you have this problem, you can park your lawn tractor on a flat surface. First make sure that your tires are evenly inflated. Lower your mower deck to the cutting position and make sure that your blades are facing sideways. Now you can measure the height of the outer edges of the cutting blades.

You can adjust your mower deck hangers until your mower blades are even. This will help to ensure that you do not have a tilted mower deck, and you will be able to cut your grass evenly again.

Uneven Ground

When you cut the grass on uneven ground, you can also end up with an uneven cut. The best way to correct this problem is to use a push mower on hills. You can also check to see if your mower is one that is designed to work on uneven ground.

If you are going to use a riding lawn mower, you need to make sure that you avoid turning on the hill. Instead, go all the way to the bottom and turn around on flat ground before going back up the hill. Do the same at the top of the hill. Keep your speed slow, and be very calculated when you choose your path.


When you go too fast, you can end up with an uneven cut. The same can happen when you go too slow. You need to find the best pace by seeing what speed gives you the best cut, and then work to maintain that speed throughout your lawn-cutting job.

Turns are another area that can end up with uneven grass. You should not turn too sharply, and you need to overlap your rows as you come around. If you leave any blades of grass untouched by the mower, you will find that there is uneven grass.


The spindle is an important part of the cutting deck of your mower. The spindles work with the pulleys to make sure that you get an even cut. If your spindle has broken or bent parts, the blades will spin unevenly, which can make it cut your grass unevenly.

You might notice that something is wrong with your spindles by hearing a squealing noise or a loud buzzing noise. You might also feel a vibration. These sounds can start and stop, but they are a sign of a problem.

If you need to replace your spindle, you can put your mower on flat ground and let it cool off. Block your tires so that it won’t roll, and lift the front. You can then remove the cover of the spindle, and remove it. It is usually held in place with bolts, so you will need a tool to remove it. Some mowers have more than one spindle, so you should remove any that are malfunctioning.

Once you resolve the issue, you can replace the spindle and secure it back where it belongs. If your mower is cutting unevenly, you should check the spindle, as this is a common culprit for this kind of problem.

Dull and Bent Blades

Another problem that can lead to uneven lawn cuts is having dull or bent blades. If the blades are dull, they won’t cut all of the blades of grass, and if they are bent, they will cut unevenly. The best thing to do is to check your mower blades and sharpen any that are dull. If you have bent blades, you can try to straighten them, but you may need to replace them.

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