Does Using A 3 Blade Mower Bring Problems or Benefits?


When looking at mowers, there are so many choices that it can be hard to know which is the best one. Hidden underneath the part known as the deck, you may have 2 or 3 blades to do the cutting. But does a 3 blade mower have problems or benefits?

3 blade mowers are a tremendous help to land owners and professional lawn crews alike. They allow quicker cut times for larger areas and their smaller blades are more cost effective to maintain. These larger machines can be a problem for smaller yards and areas with loose or wet soil.

We’ll look at the main differences between 2 and 3 blade mowers so that you can learn about what the differences actually are, and how to choose the best mower for yourself and your needs. We’ll also consider some tips on how to get your mower cutting evenly.

3 Blade Mower Deck Benefits

For larger lawns, yards, and fields a 3 blade mowing deck has become the standard in efficient mowing. Though the price may be too steep for the average homeowner and the cutting size too big, for professional crews with larger jobs or landowners with large open spaces to tackle, they can be invaluable.

The benefits of having a 3 blade mower are many. Here are just a few of the main ones to consider.

Wider Cutting Area For Faster Mowing

The biggest advantage of a 3 blade mower deck is a wider cutting path than their 2 blade rivals resulting in a significant reduction in the time you take to mow massive lawns.

This is especially true for those having large areas of land like fields that may need regular cutting. Rural areas with these large sections of grassland can be too small for larger tractors, but simply too much for many residential mowers.

Higher Blade Speed For Cleaner Cuts

The speed of the mower blades is quite different between 2 and 3 blade mowers. 2 blade mowers have bigger and longer blades than 3 blade mowers to cover the cutting area provided by the mowing deck.

This means they can’t rotate as fast as their 3 blade variations. These much larger mowing decks utilize three rotating blades that can be smaller and strategically placed. This takes load and strain off of the engine and related systems that would be overstressed if longer heavier blades were used to cover the area.

3 blade mowers can cut heavier grass easier and when it cuts grass the higher speeds can give a cleaner cut. We all know the value of speed when cutting something that is flexible. With grass blades being just that, faster blades make perfect sense.

3 Blades Allow For Larger Mowing Decks

It’s also important to note that you’re not going to have many 2 blade mowers once your deck is over 44 inches. Decks this big require 3 blades to have full coverage.

To go even a step further, without three bladed options, these mowing decks up to 72″ would simply be impractical if not impossible. Because of the three blade option for these larger mowers, their decks can now be rather enormous.

There are some reasons for this:

  • Blade weight

When trying to cover the amount of area that some mowers do today, the sheer size of single or double blades can create a problem of ever increasing demand for horsepower. The amount of energy that would be required to handle the weight of heavier and heavier blades would require exponentially larger engines and fuel consumption.

Blade weight also affects the balancing and timing of the rotation. This also affects the cut, seeing as jarring and vibration is a constant thing when mowing. The heavier the spinning blade, the more apt it is to become unlevel and experience the dreaded ‘wobble’.

  • Blade length

The length of the blade is not only going to require more weight the longer the span reaches, it is also going to cause more power to be consumed. This is a major concern when trying to achieve fuel efficiency and create mowers with engines that last.

The other consideration with longer blades is flex. No matter the material used, when spanning longer distances flex becomes an issue. This causes uneven cutting depending on the length and material.

  • Blade material

The longer the blade the lighter the material needs to be in order to get the same amount of spin as shorter lengths. These lighter weight materials then give a much greater chance of flex, cracking, or even breaking.

Though every mowing deck has to be designed with specific stress ratings in order to protect bystanders in the event of blade failure, weak blades can deliver a host of problems. Breaking is just a rather considerable danger.

This is why three blades are ideal for larger decks and solve many of these problems. But are there problems that using three blades cause in and of itself?

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3 Blade Mower Deck Issues

The addition of an extra cutting blade will bring with it more moving parts and therefore more maintenance, let alone more chances for something to go wrong mechanically.

Weight

Mowers and decks with 3 blades are noticeably heavier and sometimes larger than their 2 blade cousins. This is due to the size of the deck and the material needed to make it, not the blades themselves.

If you have issues with lifting and manipulating heavy equipment, a 3 blade mower might struggle to lift if you already have issues with a 2 blade. This can be a consideration for those changing or sharpening their own mower blades.

It should also be mentioned that these machines are harder on grass than lighter options. For those having trouble with water tables and wet soil or patches of ground that resist healthy grass growth, heavier can mean ruts or soil displacement.

Maneuverability

The bigger the unit is, the harder it is to maneuver into tight corners of your yard. If you’ve only got limited shed space, this will also probably not be the best choice.

Blocked Bagging

Another commonly reported issue revolves around the grass bag or clipping collector. The presence of a third blade can block the intake of the bag, meaning it won’t collect grass as efficiently. Some models with a central third blade are even reported to block their intakes.

Are 3 Blades Better Than 2 On A Mower?

Some are in the camp of more is always better. While others take a quality over quantity approach. The fact here is that 2 vs 3 blades depends on who is using the mower and for what. So, are 3 blades better than 2?

For larger mowing jobs that require larger mowing decks, 3 blades get the job done faster. For professional crews this is a must. For smaller jobs though, 2 blades will be better since the mowing decks will be more maneuverable and lighter. Both give a quality cut if used how they were intended.

Normally a three bladed mower will not be a common sight in a planned subdivision where lawn sizes are kept more to a minimum. Yet, for older housing developments and rural settings, yards can become rather massive. In these instances even homeowners could opt for the time saving 3 blade design.

At What Position Should Blades Be On A 3 Blade Mower Deck?

When some speak of position, they can mean a couple of things. I will briefly go over a the different ways to look at mower blades on a 3 blade deck. Some could mean orientation while others mean design layout when speaking of position.

The orientation or timing of the blades on a 3 blade mowing deck is fairly simple. They do not have to be timed, parallel, nor perpendicular in orientation. The blades do not overlap or touch. As for design, normally 3 blade placement is staggered. The center one is pushed forward.

Unlike some two bladed mowers, the blades in a 3 blade system do not overlap another blade. Instead the center blade is normally pushed forward in the design and the outer two are back and slid inward to create a slight second pass behind the first. This ensures there are no missed grass strands left uncut.

Should 3 Mower Blades Be Parallel?

As for timing the blades, it is unnecessary. 2 blade systems can require timing blades to miss one another. If not done there could be possible blade collision. This overlap is needed to ensure an even cut with no missed areas.

In 3 blade systems, the blades don’t have to be times to miss on another since placement still allows for a full cut under the deck while ensuring no blades will ever collide. The staggering of the center blade forward and the outer blades inward simply solves the issue.

3 Blade Mower Cutting Uneven

One major complaint that needs to be addressed on its own centering on 3 blade mowers is uneven cut. It is not something that is experienced by all owners, but it can be an issue with larger deck mowers.

Built-Up Debris

There are several areas to check if you’re noticing uneven cutting. The first is to open the cutting deck and get the clippings out of it. Built-up clippings will not allow airflow or may impede the internal operations.

Ground Speed

If your ground speed is too fast, this won’t give enough time for the mower to effectively cut the grass. Use your transmission to select a slower ground speed and experiment finding out the optimal speed to effective cutting ratio that your lawn needs.

The blades must be run at full throttle position on the mower. For most mowers if a RPM reading is possible, the engine should be checked and running at 3400 to 3600 RPM. 

High RPMs means that not only will the blades have enough power, but it will help create a sort of air flow pulling grass towards the blades, allowing more effective cutting.

Blade Care

Amazon stocks the Tite-Seal MDS11/6 that is specifically designed for mower deck lubrication. This product helps prevent rust and corrosion, enabling future maintenance and repairing easier.

Tite-Seal will also play the role of a protector, stopping massive amounts of grass, dirt, and moisture from accumulating under the mower deck. 

You should also check that your blades are attached and moving smoothly. Confirm that your 3 mower blades are mounted and tightened correctly. It is not necessary to make everything absolutely lock tight, follow the instructions in your manual and use a torque wrench.

If the blades are not well balanced, the vibrations and operation of your mower can cause the blade to crack at the mounting bolt holes.

The blades will blunt over time and should be examined. If you notice obvious wear or dullness, consider grabbing some replacements per the blade size recommended in your owner’s manual.

To make things easier, the blade part number is stamped on the product, generally on the back side of the blade.

Use the Height Adjuster

Mowers will come with front height adjusters, as well as other back and side adjusters. 

Each mower will have a default configuration but this may not work well on your specific lawn, especially if it is not flat ground. Check the distance from the bottom edge of the deck to the ground and compare whether it is the same on both sides.

If the deck has unevenness, once you’ve fixed it you will need to adjust the linkage or cutting component. Generally you adjust via the links on the side of the unit, the control will have the appearance of a lever for most models. 

After you have leveled the deck to the ground, you must adjust the linkage up 1/2 inch to 1 inch above the ground. 

The front of the deck has to be set to a different height to the back to enable optimal mowing. This ranges from about a 1/4 inch to 3/8 inch lower at the front of the deck compared to the back.

Tires and Alignment

Make sure that the air pressure is equal on both front and rear tires. Your size of mower and inner tube will differ slightly between models, but expect that you should get an air pressure of around 12 lbs of air pressure.

The axle or deck wheels should be measured for alignment. Bent or old axles can cause the wheels to be uneven, pulling the mower ever so slightly left or right and causing unevenness.

The Final Touches On 3 Blade Mowers…

Three blades enable mowing decks to reach some giant proportions. They have made mid to large size mowing jobs much more time and cost effective overall.

Though these beasts of machines are not for everyone. The quality of cut naturally goes down with these wider decks, even though the average home owner won’t notice any difference. If you are looking for that putting green lawn, you will be needing a reel mower anyway.

3 blade mowers are just the ticket for larger jobs and especially for professional landscaping crews. They can even fit the bill for the homeowner that is looking for that next new ‘toy’.

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Mathew Booe

Mathew has worked in landscaping professionally for over 10 years. He is a grandpa and frequently interviews other experienced landscapers and lawn care experts who are also grandpas for these articles.

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