Power comes from an FPT 12.9-litre six-cylinder engine, which gets AdBlue exhaust after-treatment to meet current Stage 3b emissions legislation.
Two-stage turbocharging helps the 550 to produce a rated output of 558hp and a peak power output of 614hp. This is no shrinking violet.
First impressions are of a towering brute, and getting to the perch requires a lofty, almost awkward climb to the cab from behind the nearside front track.
Once up there, the seating position gives a panoramic viewpoint, which makes this tractor feel smaller than its physical size first suggests. It feels narrow too, but never unstable.
The 550 is just 3m wide, compared to the MT865C’s 3.3m and 9RT’s 3.46m overall width - and that is before you put ballast on the outside of their front idlers and track frames.
Quadtrac operators get a tall cab, giving the impression you sit on the tractor, rather than in it.
Getting around the outside of the cab to clean windows and lights first requires a risk assessment and assistance from a magic carpet. The idea of self-cleaning glass, as used in conservatories, is not such a silly suggestion for cabs, although there are large grab handles to hold on to, on each of the cab’s four corners.
Tractor performance and information is shown on the right-hand A-post, while air conditioning and heating is supplied from vents tightly packed around the steering wheel console. It could be better.
Beneath this console is an Easy Rider-style steel bar on which you can rest your feet. Not the most comfortable aspect of cab trim if you want to sit with the seat slewed to the right, but ideal when the auto-steering is engaged and you just want to kick back.
A flat floor does offer plenty of open storage space, but with an opening right-hand window, it is easy to lose small items put on the floor, as they can simply roll out of the open window.
It is better to put loose items in the two tool boxes which flank the front grille and serve as steps for those who want to polish the 550’s large bonnet. When you want to delve deeper, to fold out radiators for cleaning and make daily checks, lifting the big bonnet is effortless - but getting it down again could take two pairs of hands.
The Quadtrac features a decelerator button on the cab floor, allowing you to toggle between two preset engine speeds instead of reaching for the throttle lever to ease back when making headland turns.
But with so many buttons on its armrest consoles to make life simpler, we do not understand why there is still a need to fit a decelerator to any of these tractors -pedal or button.
For instance, the 550 has two engine speeds which can be pre-set and selected via buttons. These can also be worked into a headland management sequence - much like the Challenger system.
But while the Challenger’s headland management is relatively simple to master, the Quadtrac’s is a faff, with sequences recorded only - they can be edited for refinement, but functions cannot be added. To activate a full sequence, the headland management button needs holding, or it can be pulsed for step-by-step activation.
Our 550 was fitted with the firm’s own AFS 700, top-spec terminal to monitor performance and set-up all tractor functions.
The terminal does include practically everything you need, including up to several individually tailored performance monitor screens, and a virtual terminal for implement control using IsoBus.
But navigating the large touch screen terminal is a pain. It is cluttered and there seems to have been no logical thought process from its designer - unlike the Deere’s, which is much more intuitive.
However, we do like only having one screen in the cab, which creates a little more space. The screen also duplicates a lot of the information found on the A-pillar.
Whether you are in-field or on-road, the 550 has a driving mode for it. These are selected by two buttons on the console, depicted by a plough for field, or a trailer for road. Choose neither and the tractor defaults into fully manual mode. Press road and the hand throttle then becomes a travel lever and drives like a crude CVT, which saves you juggling the throttle and transmission. Perhaps an accelerator pedal holds the key here?
For field mode, the 550 requires a bit more set-up. First you have to get up to the working/target speed you want to travel at.
Once at the desired speed, press and hold the field mode button, which remembers that speed. The hand throttle can then be used as a travel lever with your target speed as the top speed - similar to road mode. In doing this, the 550 tries to achieve the desired speed at optimum revs. This system works pretty well, but would be much easier if the target speed could be pre-programmed, much like the Challenger’s.
We found the Quadtrac’s transmission a bit lazy, particularly when downshifting. Frustration is further compounded between gears four and 13, as the transmission skips every other gear.
Single shifts can be chosen, but you also need to press a button on the rear of the hand throttle to execute a single shift.
All new Stage 3b compliant Quadtracs get automatic steering as standard, controlled via the optional AFS terminal.
Setting up the system is relatively easy, and the reaction and acquiring of the line is very good - aggressiveness of this can also be adjusted. We really liked how it learned where the field boundaries were, sounding an audible alarm when getting close. This is particularly useful if you are taking full advantage of the Easy Rider bars during night shifts.
Unlike the other two, a lot of the Quadtrac’s primary functions are located on the hand throttle, which we found convenient to use. The only thing missing from the hand throttle was a button for activating the automatic steering.
The first aspect to get used to when operating the Quadtrac is how the tractor steers. As an articulated machine, the 550 feels very different to the Challenger and Deere. It does not spin on the spot, but steers smoothly around, all the time keeping its rubber tracks firmly in contact with the soil. While you need to adjust to the quirks of pivot steering when setting back into work, the upshot is a totally undisturbed headland and supreme traction.
While the 550 might not have the yard-negotiating ability of the 9RT or MT865C, it does ride comfortably thanks to those independent track frames and the two halves of the chassis oscillating.
However, compared to the other two, which use frictional drive, with some give over a large area of their tracks, the Quadtrac uses positive lug drive over a small area, which has to cope with a lot of pressure.
Cab suspension does make you feel isolated from what is going on beneath you. As a result, there are no shocks, jolts or thumps in the back - it seems the Quadtrac has an ability to flatten out surfaces while delivering an armchair driving experience.
In standard battle dress, the 550 weighs 24,405kg - of which 1,800kg is diesel when the Quadtrac’s fuel tank is brimmed. It can also be equipped with an extra tonne of ballast, but compared to the Deere or Challenger, you could not take several tonnes off the Quadtrac to make it much more suited to low-draft top work.
But, while the other two will be waiting for their escorts to arrive, the svelte Quadtrac will be down the road and already working in the next field.
Despite its rear-end being further from the seat than the other two, it is surprisingly easy to hook up implements.
A remote control on a wander-lead for the three-point linkage provides safe and convenient hitching up, and a hefty handle on its Cat V pin also helps when some man-handling is required.
Well positioned hydraulic couplings and electrical connectors add to its user-friendliness.
What we like
What we dislike
Total (out of 100) 76