Factory-fitted four-track system is an industry first

A brand-new tracked tractor has been added to John Deere’s extensive line-up, boasting unique features likely to suit UK arable farms. David Williams took an early test-drive. Among the updated

A brand-new tracked tractor has been added to John Deere’s extensive line-up, boasting unique features likely to suit UK arable farms. David Williams took an early test-drive.

Among the updated and new models attracting considerable attention on John Deere’s stand at Agritechnica in early November were its latest 8R tractors. Representing the manufacturer’s most powerful conventional tractors, the 8R series is popular with professional users demanding maximum productivity, so its new models were eagerly anticipated. Previously the line-up included 8R (wheeled) and 8RT (twin-track) variants, with power topping out at 450hp. But the updated series provides an all-new tracked option in the form of the 8RX with four sets of rubber tracks and conventional front axle steering, and maximum power up to 458hp.

8R-series updates

Since John Deere introduced its flagship 9RX with up to 670hp (max) and four equal-sized tracks, the addition of a smaller four-tracked model in the 8R series has been widely predicted. Development and testing since development started in 2016 has been extensive but, despite the fact that this new product launch has been one of John Deere’s largest investments ever, with more than 100 test units operating, the company and customers selected to test the new model did an excellent job of keeping it under wraps and few pictures have appeared of machines working.

With the 8RX model’s official launch planned for Agritechnica this year, Farmers Guide was one of a handful of agricultural magazines from around the world invited to an exclusive press preview this summer. It was at John Deere’s Waterloo tractor production plant and, as well as seeing early units coming off the production line, there was also an extensive test-drive on fields adjacent to the factory.

The full range of 8R models has been updated and, from the outside, the most obvious change is revised styling.

There are five new 8R wheeled models ranging from 280–410 rated horsepower, and John Deere claims class-leading efficiency for the latest line-up with up to 94 per cent total tractor efficiency. All the new models are backed by John Deere’s Fuel Guarantee Programme from the start, for both field and transport tasks.

Power and efficiency

All 8R-series models are powered by John Deere 9-litre PowerTech PVS and PSS engines and meet the latest Stage 5 emissions standards.

The engines are similar to previous models but with extra power, and a new eVisco radiator fan improves cooling efficiency.

Transmission options include 16/5 PowerShift for wheeled models up to the 8R 340, and the e23 with Efficiency Manager is available across the range. AutoPowr IVT is an option for all models except the most powerful 8R 410.

The rear brakes are upgraded, with double the performance of previous versions and can stop the tractor from 50kph more quickly than previous models could from 40kph. The rear brakes are so effective that front brakes aren’t needed up to 50kph, but can be ordered as an option.

Cab upgrades

Cab access is improved with 25 per cent wider steps. The door handle is lowered, making it easier to reach from the ground and the opening angle is wider. Right hand side steps are now included in base configuration. There are new lights making it easier to approach and leave the cab in the dark.

The mirrors are improved, and there is an integrated front camera.

Externally the cab is similar to before but inside it feels much larger. The cab ceiling is 5cm higher as the air conditioning has been uprated and relocated under the cab.

The 8R-series cabs have always been popular for their low sound levels, but the latest design is even quieter.

Another improvement on the latest models is the fridge, which is easier to access and has double the previous capacity at 11 litres.

In-cab entertainment is controlled through a 6.5in touch-display, with Apple CarPlay compatibility and improved Bluetooth connectivity. Sound quality for phone calls
and media is enhanced.

Precision agriculture upgrades include the latest StarFire 6000 integrated satellite receiver, which acquires a satellite signal faster from start-up and provides 30 per cent greater accuracy at speeds over 15kph. It can also provide accurate guidance down to just 100m/hr.

On-line field management including field boundaries, guidance lines, and set-up data, as well as crop planning and documentation can all be managed through the web-based MyJohnDeere Operations Centre platform. A new feature coming in 2020 is AutoSetup, making it possible to download all field, machine and implement data for individual jobs direct to the tractor. This makes the tractor ready for use immediately it arrives at the field and reduces the possibility of errors.

There are four specification levels; including Signature, Ultimate, Premium and Select. Top variants include top level seat, infotainment, refrigerator, lighting, mirrors, cameras, CommandCentre and activations. JD-Link Connect telematics is available for all versions and comes with the Connectivity Package including five years’ subscription.

The award-winning CommandPro joystick, introduced previously on largest models in the 6R range, is available with AutoPowr IVT transmission.

Self-cancelling indicators have been added and a new e-Active seat is now available with integrated heating and cooling, plus a two-zone, two-mode massage system to improve comfort during long working days. Seat suspension is improved. The seat can be swivelled 40 degrees right and 25 degrees left, and an additional footrest near the front right-hand cab pillar increases operator comfort.

Track system development

John Deere developed the 8RX in response to growing demand for a versatile tractor offering improved soil protection for a wide range of
field tasks, from heavy cultivations to top work.

Alternative solutions were considered, including half-tracks and bolt-on four-track conversions, but these were rejected for
various reasons.

John Deere’s solution is a tractor specifically designed for tracks front and rear. The track units were developed for the application, and sized for optimum flotation, grip and manoeuvrability. The engine, cab and transmission are shared across the 8R range, but RX models have beefed- up axles, suspension and steering.

The result is a tractor which allows users to make the most of its performance and capability in all situations. Drive to the tracks is positive rather than friction, the overall width is under 3m, and maximum speed is 40kph even for continuous operation at maximum weight.And the 8RX’s clever design and construction means that there are no additional speed or use restrictions.

Steering action is similar to wheeled models, and avoids ridging, which can occur during tight headland turns by twin-track machines. When turning, the pivot point is below the centre of the rear axle, similar to wheeled versions, and the tracks remain firmly planted on the ground. Stability and steering performance on sides-slopes is also improved over twin-track machines. Ground pressure is significantly less than for wheeled models at under 0.5-bar, even at maximum weight, and there is even less soil disturbance, making the 8RX ideal for seedbed preparation and drilling.

A primary objective was equal weight distribution between the axles for maximum flotation; reducing compaction and soil damage. The new 8RX achieves a 50/50 split, with 2–4 per cent slip. The ground contact area is 20 per cent greater than for an 8RT twin-track model fitted with 30in tracks, and the turning radius is almost 2m less than an equivalent 8R tractor on large front tyres. New four-point cab suspension ensures a smooth ride on the rubber bands, and there is no front axle suspension as tests showed no benefit over the long tracks’ natural ride improvement due to their bridging effect.

Maximum gross weight is 24t, of which 18.7t is the vehicle’s unladen weight. John Deere explained that for most applications the equal weight distribution and effective grip means no additional ballast will be needed.

The 8RX line-up includes four models – the 310, 340, 370 and 410.

Test-drive

The 8RX test drive included a 370 model with a wide trailed cultivator. With AutoPowr IVT transmission, the combination quickly achieved target speed after headland turns, and the engine revs reduced for greater fuel economy as soon as the set cruise speed was achieved. The cab was quiet, there was little noise from the track units and the new cab suspension and premium seat gave a comfortable ride.

Starting off under full power with the cultivator in the ground, there was no sign of track slip. When turning at the headlands the tight turning radius was impressive. The steering felt little different to comparable wheeled models – it was light and precise, and watching the tracks during tight turns they gripped well, without creating ridges in the loose soil. With the implement raised out of work, only the cleat patterns from the front and rear tracks were visible, and the surface remained level.

Visibility was excellent, including to the front where the wide-set tracks allowed a clear view down past the sides of the engine. At the rear there was a clear view of the drawbar and implement.

The demonstration provided plenty of opportunity to assess the new track system’s performance on land, which would have revealed any shortcomings, and the results were impressive. With growing attention to looking after soils and reducing compaction, while also offering flexibility for a wide range of tasks; John Deere’s new 8RX tractors are bound to be popular and dealers will be busy next year satisfying demand for demonstrations.

Twin-track updates

John Deere’s popular twin-track 8RT series remains available, offering alternative performance advantages to the new 8RX.

Four 8RT models are available in new 310, 340, 370 and 410 variants.

The 8RT’s large rubber twin-tracks are ideal for straight line pulling tasks on dryer, loose soils which means it is likely to be selected for the heaviest draft work, including primary cultivations.

Like other 8R models, the most obvious identifier of the latest version is the new styling and the cab shares the improvements of other models in the latest 8R series.

Battery over-heating was an occasional issue on previous versions, and on the latest models it’s repositioned at the rear where ambient heat is reduced.

Ballast weights have been improved for easier fitting and removal.

New electric transmission

Also revealed for the first time during Farmers Guide’s visit was a new electric drive transmission which will be available for the 8R series within two years.

The exclusive press event included a visit to the research and development centre, where there was an opportunity to meet the team responsible for the new drive system.

John Deere has displayed several concept electric drives previously, but the new eAutoPowr transmission remained a close-guarded secret until now, despite having been in development since 2011.

eAutoPowr works on a similar principle to the current AutoPowr IVT transmission, offering stepless speed selection over the full range. The main difference is that in a conventional IVT transmission, drive is through a combination of hydraulic and mechanical paths, with hydraulic pumps adjusting power delivery for stepless speed control. In the eAutoPowr transmission the more efficient mechanical drive components are retained, but the less efficient hydraulic drive section is replaced by two extremely durable brushless electric motors. One is direct coupled to the engine, so operates at engine speed and the second motor is coupled to the planetary gears. Mode selection is through a drive system similar to the e23 transmission’s power-shift components. In mode 1, all the drive is electric, whereas when full power is needed mode 2 is selected for full mechanical drive.

Electrical power is from a generator between the flywheel and transmission and, as well as powering the transmission and drive wheels, electricity can also be supplied to power implements and attachments through a pair of rear sockets. Each socket is capable of supplying the total 100kW available, or a proportion of the total can be supplied through each. Supply is managed by the tractor’s systems, and all that is required from the implement is information regarding the power and frequency needed.

Like the established AutoPowr transmission – with automatic performance management, the engine maintains the minimum revs to supply the electrical power needed. Asked why John Deere hasn’t removed the gearbox completely and adopted direct electric drive through wheel motors instead, the design team explained that the current mechanical transmission is extremely efficient with minimal power losses, and there is no need to replace it.

As well as providing external electrical power for implements, eAutoPowr models retain a conventional PTO for compatibility with existing machinery. The PTO drive is direct mechanical with minimal power loss. Changing to electric PTO drive would reduce efficiency as the engine’s mechanical power output would have to be converted to electrical power, then back to mechanical power to drive the PTO and implement.

Hydraulic pumps and services retain current mechanical drive which is efficient; but it was acknowledged that potential benefits of changing to electric drive in future would include greater control and easier automation.

User benefits

For users, speed control through electric drive is easier and more precise, and acceleration is also improved.

A further advantage, according to the engineers, is that with electric drive replacing the hydraulic component of the IVT unit, the result is an almost totally silent transmission.

Maximum gains over the standard IVT unit are available under partial or variable load, when electric propulsion replaces less efficient hydraulic drive. This means that, for constant heavy draft work when drive through the transmission is direct mechanical, a tractor with the new transmission will provide similar efficiency to AutoPowr models. But in a partial load situation and where the load varies, the new system offers greater efficiency and fuel economy.

John Deere’s current 8R series tractors are recognised for their class-leading fuel efficiency, and with the new electric drive transmission, performance figures should be even better.

Practical application

John Deere has worked with Joskin developing a tractor and slurry tanker combination which optimises drive performance using electrical power from the tractor. Two of the tanker’s drive axles are powered by a 100kW electric motor – operated through a standard AEF ISO socket. The result is precisely controlled driven wheels on the tanker which provide traction, reducing wheel slip and ground damage. Potential future developments include using smaller tractors to pull wider implements, with optimum use made of the engine power available by distributing it through electrical cables to where it is most useful. The design engineers explained that combined tractor and implements solutions using electrical power offer real potential for improved efficiency and cost savings.

Using some of the power available to drive an implement’s wheels could allow up to double the working width behind the same tractor, but at lower speeds. This would result in a typical work rate increase of 45 per cent, overall fuel savings of 45 per cent, and a 25 per cent saving in production costs per hectare.

Further potential for John Deere’s new system includes use of the tractor as a portable generator, with either 700V of DC current, or 480V of variable frequency three-phase AC available.

The new eAutoPowr transmission won the only Gold Medal awarded at this year’s Agritechnica, and the system is expected to be available for a limited number of 8R-series models by late 2021.

7R updates

New 7R-series tractors were also demonstrated during the American press event, and the highlight was a new flagship for the five-model line-up. The 7R 330 has up to 373hp available with Intelligent Power Management for certain situations.

The engines use a combined DOC and DPF within one package which keeps the unit compact, improving visibility and styling. No change to the engines was required to meet latest Stage 5 emissions regulations as previous 7R models already achieved the standard.

Transmission options include e23 powershift or AutoPowr IVT, but for the latest 7R series with AutoPowr transmission a new option is the CommandPro joystick.

The cab is new, with the same specification as 8R-series models.

Like the 8R series, an 11-litre fridge is available, and an improved 360-degree LED lighting system provides 60 per cent more illumination than the previous top-specification option.

The same upgraded media package is available, operated through a 6.5in touchscreen.

Cab access is easier, and approach and departure lighting is added with timed operation. The cab suspension is also improved.

Precision farming upgrades include the Starfire 6000 integrated satellite receiver, and wireless data transfer to the John Deere Operations Centre is provided free-of-charge for up to five years when the Connectivity Package is ordered.

AutoSetup is also available.

JDLink telematics allows remote tractor monitoring, and recent service upgrades include Expert Alerts, through which dealers can be authorised to monitor performance data, allowing fault prediction and correction before they occur.

“The 7R series has benefitted from many updates in recent years and is respected by users and dealers for its performance and reliability. The latest updates provide further improvements and additional features,” explained product specialist Dave Gutterman.