AUTOCAR ROAD TEST 5789

JOHN DEERE 9RX 830

The world’s most powerful tractor ploughs through the pages of Autocar

PHOTOGRAPHY MAX EDLESTON

With impressive understatement the John Deere website refers to its 9RX range of agricultural machinery as “high-horsepower tractors”.

We always like it when the Christmas road test has a unique claim to fame: the biggest, the newest, the fastest or whatever it might be. And this year’s Christmas road test subject takes that ‘high horsepower’ to a level not seen in – ahem – its field before, because it is the most powerful series-production tractor in the world. Here we have the John Deere 9RX 830, the ‘9RX’ referring to its series model name, with the numeric suffix bearing a loose connection to its power output. There are also 640, 710 and 770 tractors in this range, although they all make more than their named and rated horsepower, because on overboost the 830 will produce 913bhp. Unlike in a car, which may only make a peak overboosted output for a short amount of time, the John Deere can sustain this peak figure for hours at a time.

This capability for continuous high-load performance is an important one, because the 9RX 830 is a vehicle that can and will operate for hour upon hour. To do that it has to be not only extremely capable and reliable but also accommodatingly comfortable and usable for its operator. Although there is an element of automation in modern agriculture – as we’ll see – fundamentally this will mostly be a one-person-operated machine that’s out working in all weathers, and at certain times of the year it would be one of an arable farm’s most intensively used pieces of equipment.

DESIGN & ENGINEERING

★★★★★

Even if you spend a lot of time in the British countryside you’ll note that, although there are a few very large articulated tractors like this on the market, models like the 9RX tend to be an unusual sight here. That’s because the UK is not a particularly large country and, by global standards, our fields aren’t big enough to make the most of them. This tractor’s size, purpose and price will only appeal to the biggest British arable farms.

The machine’s purpose is a relatively simple one: the 9RX is a tool for towing large implements across big fields. The idea is that the larger implement you can pull, and the faster you can do it, the fewer passes you have to make and less time it takes to cover the same ground as in a smaller tractor. When windows of opportunity between weather are small, such considerations become quite important. And ultimately it adds up to more profit.

To drag a large implement across a big field you need a certain number of things. One of those is traction and grip on the ground, another one is weight in the towing machine and the third is the power to make full use of the first two.

Even if you tow a caravan or a trailer behind a car you’ll know about all of those things, and the same principles of physics apply here, except on a much bigger scale. In this case, that scale is 8.8m of overall length, 3.8m high and just under three metres wide.