The tractor model numbers are comprised of four positions. The first number designates the family while the next three numbers represent the approximate engine horsepower. The fifth and sixth positions are represented by a letter. The first letter indicates the level of capability or price a tractor has. Not every tractor will have a second letter. But if it does, the second letter represents a special configuration of the tractor.
The size of the tractor is how large the tractor is compared to other tractors John Deere offers, using the similar sizes of today's product groupings and still sustaining the tradition of the name and numbering legacy. A lot of people refer to these tractors as a "Six" Series Tractor. This name and numbering system will not change that. The 6D is similar in size to the 6003 Series.
The second position is the tractor's approximate engine horsepower. 6110D at 99 engine horsepower, 6115D at 118 horsepower, and 6140D at 138 engine horsepower have been rounded to the nearest 5 horsepower. John Deere has promoted PTO horsepower for its utility and row-crop tractors and engine horsepower for its 4WD tractors. This has lead to some confusion in the marketplace. Although promoting PTO horsepower has its benefits, using bare-engine horsepower allows for a more consistent means of promoting tractor horsepower in a global market. Bare-engine horsepower is measured by running just the bare block engine with the front fan. With "bare" engine horsepower, John Deere is using the International Organization for Standardization (ISO) 97/68 E-C standard for determining the bare-engine horsepower at rated engine speed, given in metric horsepower, not SAE. This unit of measurement is used globally to describe off-road engines. This will allow John Deere to consistently promote the tractor's approximate horsepower within the model number across all tractors around the world.
The third position is the tractor's capability or price level within its family. In general terms, "capability" is the specification level of that tractor series, such as the type of engine, transmission, frame, and overall design; all leading to price. The letter D would equal a very basic tractor, M would signify a premium tractor, while the letter R would equal a very premium tractor with many options and features. The higher the letter is in the alphabet the higher the tractor's spec level. If the tractor has a second letter, the second letter represents the configuration of the tractor. For example H will designate high-crop and V will designate a vineyard design.
Another important part of the name and number system is the way that you pronounce these tractor models. Using the former system we would have said "sixty-one-forty-D," but since the second, third, and fourth positions are the engine horsepower and not part of the tractor's size, the numbers need to be separated.
The correct way to say this tractor lineup is
This is a significant change to what we've all been use to for years, but the value and the solutions of these tractors remain the same.