Machinery Chatter

John Deere Goes Four-Track

Jim Patrico
By  Jim Patrico , Progressive Farmer Senior Editor
The new 9RX tractor marks John Deere's first entry into the four-track category and rounds out its 9 Series, which already had wheels and two tracks. (Photo courtesy John Deere)

WATERLOO, Iowa (DTN) -- Tracked-tractor users have another option to consider. John Deere used its Waterloo tractor factory on Tuesday as the site to introduce the 9RX Series of high horsepower tracked tractors. Deere's 9 Series tractors now have wheels, two tracks and four tracks to accompany its 9RT Series.

Why four tracks? Articulated tractors with four tracks are better than non-articulating tractors with two tracks for some customers' circumstances, said Jerry Griffith, John Deere mid- and large-tractor product marketing manager. With their long, powerful bases, two tracks give excellent straight-line pulling, but they tend to slip during turns. Because the 9RX is articulated, they are more maneuverable. "Four tracks can turn better under load than two tracks," Griffith said.

Another advantage: When working near wet areas, four tracks will let you get closer than two tracks. If you get too close to a wet area with a two-track tractor, the inside track can slip and spin faster. When that happens, steering can become tricky. "If you get into trouble with a four-track tractor, you are better able to get out of it because it is articulated," Griffith said.

That same articulation can help on sidehills when pulling an implement. With two tracks, an implement that drifts downhill can cause steering issues that require a driver to have to compensate more. Articulation helps a four-track tractor "stick to the hill better," Griffith said.

And, when going over hills -- terraces, for instance -- a two-track vehicle gives a teeter-totter effect: The front goes up, up up and when it reaches the center point, it comes down quickly. Not so with an articulated tractor, which flexes in the middle to glide better over the incline.

The 9RX oscillates 15 degrees side-to-side at the center of the tractor and 20 degrees up and down at the undercarriage. It has a turning radius of less than 20 feet.

DIFFERENT THAN COMPETITORS

It's inevitable when talking about the 9RX to compare it to the Case IH Quadtrac, which has been on the market since 1996. One key difference, Griffith said, is the 9RX's unique undercarriage, which is taller than the competitor and has larger drive wheels. Its configuration makes the track itself 20% longer, which means 20% less travel, 20% less wear and longer track life.

Deere designed the new undercarriage to be low maintenance. For instance, the operator will have to check oil in the sealed cartridge mid-rollers only every 1,500 hours and change oil every 10,000 hours. The 9RX uses the same mid-rollers as the 8RTs, which means the design is proven and parts are already available. And, if they ever have to be replaced, only eight bolts must be removed.

The tracks on a 9RX have a positive drive mechanism; inside drive lugs engage with sprockets. Outside tread bars are for traction. The result is an extremely efficient transfer of power to the ground. By contrast, two-track systems rely on friction. Large rear drive wheels engage tracks rubber to metal and inside track lugs are guides to keep the tracks centered on the drive wheel; they do not transfer power. Such a friction-based system works well with large drive wheels. It would not work as well on four-track systems because their drive wheels are not as large, and friction would be less efficient than on positive drive.

OTHER FEATURES

The 9RX comes in four models ranging from 470 to 620 hp. The 9470RX and 9520RX feature the John Deere PowerTech PSS 13.5 liter; the 9570RX and 9620RX are equipped with a Cummins QSX15.

Rubber tracks are Camso Duradrive 3500 and 6500 Series and come in 30- and 36-inch widths. The 9RX undercarriage will be set at an 87-inch spacing. While that spacing and those track widths are not ideal for planting or cultivation in 30-inch rows, Griffith said, Deere is investigating other spacings and is also considering narrower tracks that would allow row-crop applications.

Total width when equipped to 30-inch track belts will be about 10 feet, which will make the 9RX narrow enough for road travel. Roading speeds are 26 mph, same as other 9R and 9RT tractors.

The tractors will be correctly ballasted at the factory, Griffith said. Customers will not have to add weight to improve traction.

FAMILY TRAITS

Because it is in the R Series tractor family, the 9RX shares some important technologies and features with its siblings. But cab suspension is a unique design for the 9RX. Tracked tractors are not known for their comfortable rides, so Deere engineered what it calls a Parallel Plane Four Bar Linkage to isolate the cab from the chassis and to control its movement vertically and horizontally. The cab has a 4-inch vertical travel and 2-inch movement to each side.

As with the other 9R Series tractors, the 9RX comes with a CommandView III cab, a Generation 4 CommandCenter and optional Active Command Steering to reduce steering effort. It also has an e18 Transmission with Efficiency Manager to optimize fuel use. The 9RXs are fully equipped with Farmsight capabilities.

TARGET MARKETS

High horsepower tracked tractors typically are popular for air seeding in wide open spaces like the Red River Valley, the Great Plains and western Canada. More and more they have turned up in the Corn Belt and the South as powerful tillage tools.

Because they are low-compaction machines, Griffith said, tracked tractors appeal to farmers in wet areas because they, "maximize the opportunity to get seed into the ground ... Increased floatation can make a two to three day difference in the spring" and farmers "might be able to stay in the field longer if it starts to rain than if they are in a wheeled tractor."

The 9RX won't be for everyone and it probably won't be anyone's only tractor. "This will be one of the tractors in a farmer's arsenal," Griffith said.

The new tractors are available for order now with delivery in late spring 2016. The 9RX tractors will cost about 14% more than comparable horsepower 9RTs.

Jim Patrico can be reached at jim.patrico@dtn.com

Follow Jim Patrico on Twitter @jimpatrico

(CZ/BAS)

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