What Size Combine Harvester Do You Need? | Understanding Combine Classes

A combine is an essential piece of farming equipment that makes harvesting far easier and much more efficient for farmers. They also come in various classes. If you’re a new farmer, it’s difficult to keep track of all options. You may be asking yourself which combine class you should pick when it’s time to buy a used combine harvester? And is the combine class the biggest thing you should consider? 

When choosing a combine, your primary consideration should be the size of your farm and the functionality you require. Elements like the unloading rate and grain tank volume are key considerations. Whether it’s a high or low-class combine, it should be economical, reliable, and fit your farm’s operational needs.

If you plan on buying a used combine to assist you with your farming operations, make sure you get the right machine! Read on to understand more about combine classes and find out how to get the most suitable class size for your farm.

What Is A Combine Harvester? 

As the name suggests, a combine harvester will combine three separate harvesting operations, reaping, threshing and winnowing, into a single process. A combine can harvest a variety of crops like wheat, corn, oats, barley, rye, sorghum, sunflowers, flax and canola. 

Combines can be categorised based on their working mechanisms and surfaces. Combine sizes are classified into classes, ranging from 5-10, according to their engine power. The best way to remember it is: the higher the class number, the larger the combine size is

Combines have had quite the transformation over the decades. It wasn’t until the 1980s that combines onboard electronics and self-propelling technologies were introduced. Earlier versions of the combine were horse-drawn and tractor-pulled models. Combines have since continued to get better in terms of technology and design to meet the growing needs of the farming industry. 

Modern combines now allow you to measure and assess their operation, as well as obtain field data. Advanced models also come with automation systems that allow for optimised performance no matter how inexperienced or expert the person behind the wheel is. Some combine systems even have apps that can be used remotely to monitor its performance and adjust the rotor, fan speed, chaffer, concave clearance, and sieve clearance settings.

What Does a Combine Class Mean?

A combine class describes the category or grouping of combine models. These classifications started in the early 2000s and are decided by the Association of Equipment Manufacturers (AEM). The combine class guidelines often change as AEM review them annually, so class rankings are not permanent. 

For example, the guidelines for early class 8 combines was 375 horsepower. But today, combines in a class 8 ranking are defined by much higher horsepower, sitting at around 500-600 hp. Therefore, the next generation of lower-class combines may be as big and have as much horsepower as early high-class combines did.

These changes in class size are said to be associated with the growing farm sizes and the need for more timely harvesting. 

What Determines the Class of a Combine?

The class of a combine is determined by the machine’s engine power, which is measured in horsepower or kilowatts. Combines with higher horsepower have higher class numbers. And obviously, a lower horsepower equals a lower combine class. 

How Many Classes of Combines Are There? 

There are six classes of combines on the market, ranging from classes 5 to 10.

There weren’t always this many combine classes. Class 7 combines have only existed since 1980, beginning with the Gleaner N7 combine. Class 8 and 9 combines first appeared in 2003 and 2006, respectively. Meanwhile, the class 10 combine was only first released in 2013.

As more large combines were added to the market, they soared in popularity. However, there are practical limitations that come with these high-class combines. In 2019, class 9 and 10 combines only made up 10% of combines sold. Since no new combine classes have been introduced since 2013, the farming industry may have reached its capacity in combine classes for the foreseeable future.

What Are the Classes of Combines?

The combine classes available in the market today range from class 5 to class 10. Classes 5-6 of combines are considered small, while those in classes 7-10 are regarded as large combines. The table below shows these classes and their associated engine power.

Table 1. Classification of combine harvesters as of January 2021. 

5 Less than 280
6 280-360
7 360-500
8 500-600
9 600-680
10 Over 680

Does Combine Class Really Matter? 

Yes, combine class does matter in terms of their productivity, efficiency and suitability to farm and crop conditions. For example, if you have steep, hilly farms, you probably won’t use very large combines. With their enormous sizes, large combines won’t be able to reach all the areas of your farm. Combine classes may also have practical limitations related to logistics and engineering.

Combine class is also important for classification discussion. In particular, institutions like AEM use this classification to monitor and report units sold over time to investors, manufacturers, the media, and other stakeholders. However, combine classes should not be used as the sole reference for the capacity or performance of any combine. Although it’s intended to gauge performance potential, different classes also have different capacities that may be useful under varying field conditions and crops. 

During the time of walk-behind combines with direct-feed cylinders, combine capacity was determined by walker width and cylinder width. This changed when the circular flow designs with eclipsed cylinders came. Today, combine capacity depends on cleaning shoe area and engine power.

How Do I Know Which Combine Class I Need?

In deciding which combine class to buy, you should first consider the size of your farm and your farm’s operation. The combine’s main activity centre, the processor, and the configurations should suit your farming activities. These factors can influence a combine’s efficiency. 

Although it can be tempting and seem like a great idea to get a larger combine with a higher production level, bigger doesn’t always mean better. If it’s not the correct fit for your farming capabilities, it will mean losses for you in the long term. A machine that can produce an easily handled load is better than a large combine that sits full and idle whilst waiting for pickup. 

Meanwhile, if you own a large commercial farm, large combines with high-speed auger and greater tank capacity are good options to save on labour costs and make the operation more efficient.

Other factors to consider are the grain header, auger, and unloading time. The capacity of a combine should not be greater than what the gathering head can take in. The boards also need to be able to close and protect their load when there’s rain. With regard to unloading the auger, it should have plenty of reach to get out past the widest grain you plan on using. The unloading rate is also essential because you wouldn’t want to waste time unloading your crop.

Cost is another major factor you should take into consideration. With their complex technology and size, the price of a combine, depending on its class, can go beyond half a million dollars. It’s an investment that doesn’t come cheap, so it should be carefully thought through.

Related Questions

What Is the Biggest Combine?

As of 2020, the Claas Lexion 8900 is considered the biggest combine in the world. It’s a powerful combine from the Lexion 8000 series that features a maximum engine power of 790 HP and a grain tank capacity of 18,000 L. Its weight without headers is 22,400 kg, and its unloading rate is 180 L/sec. The Claas Lexion 8900 also has a brand new threshing system called APS Sunflower Hybrid.

Other big combines are New Holland CR10.90, Case IH 8250 Axial-Flow, John Deere S700 and AGCO Fendt IDEAL 9T.  

How Much Horsepower Does a Combine Have?

A combine has different engine power ratings, depending on its class. The smallest combine class (5) has less than 280 hp, while the largest (10) has over 680 hp. Class 6 has an engine power within the range of 280-360 hp, class 7 is 360-500 hp, class 8 has 500-600 hp, and class 9 is within 600-680 hp.

Ben Boekeman

Ben Boekeman

Ben Boekeman is head of Sales & Precision Farming at Boekeman Machinery and a third-generation member of the Boekeman family. Working out of our Wongan Hills branch, Ben is passionate about the agricultural industry and the future of precision agriculture.

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Boekeman Machinery is a family run Machinery Dealership in the Central Wheatbelt, Western Australia. We have 4 branches located in Dalwallinu, Dowerin, Northam and Wongan Hills.

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