As McCormick continues to launch new tractor models at a pace, we check out its latest development, a CVT version of its X7 series. James Rickard reports.
It has been two years since McCormick took the revolutionary step and launched a brand new range of tractors, the X7.
Spanning 143-212hp and comprising three, four-cylinder models and thee, six-cylinder models, the range was initially available as powershift Pro Drive versions only, until now.
Sticking with its ZF transmission supplier, McCormick is now offering the X7 with a continuously variable transmission (CVT), known as VT Drive.
For those of you with a good memory, McCormick is no stranger to CVT technology, having dabbled with a prototype CVT version of a XTX in 2005. It too used a ZF transmission, but stuck with McCormick’s own rear frame and transaxle. However, after the announcement McCormick’s transmission plant in St Dizier, France was to close, the project was scrapped.
But with a new family of tractors and a wider acceptance of CVTs, McCormick reckons now is the time for CVT models in its line-up.
A CVT is available on all X7 models, barring the top model as its engine torque exceeds the threshold set by ZF for this transmission.
A new 12in touch screen terminal, the Data Screen Manager (DSM), is installed on the X7 VT Drive models – optional on the X7 Pro, affording greater tractor functionality, as well as implement control and set-up via IsoBus.
Fitted as standard to VT Drive tractors, our test drive of a X7.670 VT Drive, gave us the opportunity to try out both latest additions. Having test driven both the four-cylinder and six-cylinder powershift versions of the X7 (LINKS HERE), we were keen to see what the tractor was like with a CVT.
To find out, we carried out various tasks including draft work with a 4m Simba Solo and five-furrow Amazone plough, and pto and transport work with a 14t muck spreader.
For those unfamiliar with the ZF Terramatic transmission used in the X7, it comprises a hydrostatic pump and motor, and four mechanical ranges, of which it automatically changes through almost without you knowing it.
As the operator, you do not have control when these ranges change, you only tell the tractor what speed to achieve. It is then left to the engine and transmission, via McCormick’s control systems, to decide the most suitable engine revs and CVT ratio for the job in hand. Essentially, the tractor will always try and select the most economical operating speeds by keeping engine revs down and CVT ratios up.
However, for pto applications, or to keep revs up for maximum hydraulic flow, the tractor can be operated manually by independently selecting engine revs, via the hand throttle, and forward speed by a variety of ways described below. The system automatically recognises when you have engaged the pto and adopts the appropriate control strategy, so no specific selection is needed.
Control of speed is via the EasyPilot handle as used on the Pro Drive powershift versions. However, for VT Drive models, the handle also moves; forwards to go faster, backwards to go slower.
It is a force-based system, so the more you push it, the quicker the transmission reacts. A detent in the middle of the lever’s travel signifies pushing from low to high reaction characteristics. The lever also features a decent amount of resistance, avoiding any accidental movements.
Buttons incorporated into the lever, used for powershift changes on the Pro Drive versions, can be used for fine adjustment of speeds.
The transmission can be set up into four virtual ranges via the terminal, with the three lower ranges adjustable and the top range fixed at top speed. Virtual ranges can then be flicked through via the fine tune buttons, in combination with a ‘consent’ button on the back of the lever. The virtual range you are in is shown on the dash and on the DSM screen, including the maximum speed setting of each.
As well as the lever, the accelerator/travel pedal can be used for speed selection. Also, within each of the ranges you get the full range of pedal travel. For example, in a virtual range limited to 10kph, off the pedal is 0.5kph or less, while fully on the pedal is 10kph. This allows for more accurate control particularly at slow speeds.
Between the pedal and the handle, whichever one is used last, it has control of speed selection, with no need to manually select which one is used.
In addition to the virtual ranges, two forward cruise speeds and two reverse cruise speeds can be set by getting up to the desired speed then pressing and holding the cruise button. Cruise speeds can also be fine-tuned on the move and, like in a car, can be over-ridden momentarily without losing the setting.
While all of the above does sound quite daunting, in reality it is simple and intuitive to operate, and offers a large amount of tailoring to the operator’s preferences or the job.
Unlike many other CVT tractors on the market, which come to a complete stop and often hold themselves when you take your foot off the accelerator, McCormick have tuned its CVT to be more akin to driving an automatic car, with the tractor continuing to ‘creep’ on at 0.5kph when your foot comes off the pedal. A touch of the foot brake pedal is then required to make the tractor come to a halt and electronically engage the powered hold feature.
While this concept is fine for pto and transport applications, under heavy draft load it is very noticeable when the drive disconnects as you press the brake pedal
If a working speed below 0.5kph is required, then the ‘fine tune’ buttons need to be used.
Shuttling forwards and backwards can be done in three ways; by the left hand, column-mounted lever; a button on the Easy Pilot control lever in combination with the consent button; or moving the Easy Pilot lever in combination with the consent button.
The first two offer quite snappy direction changes, while the latter is more progressive, bringing the tractor to a stop before going into reverse.
For road work and pto applications, the new transmission option proved to be a smooth and responsive performer.
It was a similar story for draft work too. However, under heavy load you can feel the mechanical range changes, particularly if you work at the same forward speed the transmission likes to make a range change. In our case, ploughing at 5kph, the transmission sometimes could not make up its mind which range to be in.
To get around this ‘fishing for ranges,’ there is a button which you can press which will ‘freeze’ the transmission, and then make the engine adapt to changing loads.
As well as the new transmission, there is the new Data Screen Manager touch screen terminal.
Developed in conjunction with a company called Wachendorff Elektronik, which is part of Topcon, the 12in screen affords set-up of all tractor functions, along with the ability to control implements via IsoBus. While it is standard on VT Drive models and optional on Pro Drive machines, it is not retrofitable to already sold X7s.
Primarily, the screen operates in two levels; a home screen which is like a virtual dash showing speed, revs, virtual ranges, hitch position and pto speed; and an applications menu through which all tractor settings can be accessed and adjusted.
And it could not be simpler – find the symbol of the element you want to adjust, hit it, then adjust it.
Navigation is easy, however, it can be a little tardy to react when trying to alter something like hydraulic flow rate, for example. And it does reflect light a lot – needs some sort of anti-glare film, although McCormick says that new software with day and night modes address this criticism. That said, it is a lot easier than having to go through the dash.
We were looking forward to using the tractor’s headland management system, but we will have to wait a little bit longer for that, as we will for assignable buttons on the console’s joystick, until software upgrades are completed.
For optional guidance, auto-steering and section control, a second screen is used courtesy of TopCon with its X25 unit.
According to McCormick, most people prefer to use two screens to monitor two different elements. On the flip side, an extra screen is just more cab space taken up.
Those familiar with Topcon screens will know it is a decent bit of kit, again, very graphically led for ease of use and set up. It is a shame there is not an automatic guidance activation button incorporated into the Easy Pilot lever.
CVT tractors are a new territory for McCormick, particularly its customers and dealers, and while the overall tractor market is amiable to CVTs, will current McCormick users be as receptive to the new technology?
To be fair, they have nothing to fear. CVT tractors are like sliced bread; once you have tried one, you do not want to go back to changing gears. And the simplicity of control with which the VT Drive machines offer will go a long way towards tempting current and new customers to the McCormick brand.
However, the jury is still out on McCormick’s tuning of the CVT, which sees the tractor creep on rather than come to a halt. It does mean you always need the brake pedal to stop and engage ‘hold’ and can never truly drive it on either the pedal or the Easy Pilot lever alone. Like many things, it takes a bit of getting used to.
Overall, the new VT Drive models do offer extra operation convenience, and should appeal to those who seek finer speed control.