The worlds biggest tractor - Challenger MT975

Big Dog

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The worlds biggest tractor - Challenger MT975

As tractors go, the Challenger MT975B is big and as it turns out for UK growers, just too big. It's based on a similar concept to the all-American Steiger and Versatile artics, but the whole thing has been built on an altogether bigger scale.

The MT975B is the largest in Challenger's MT900B range and has been primarily designed for the North American and eastern European markets and has not been homologated for Western Europe. With peak power output in excess of 600hp and a maximum operating weight of just over 27t, it's the world's biggest and most powerful production tractor.

Everything about this machine is monstrous - its fuel tank takes a good 20 minutes to fill and matches most farm sprayers at 1500 litres - some indication of the 18.1-litre engine's thirst.

The size of a small suburban semi and with a pricetag to match, it's got the widest and heaviest frame in the industry (1321mm wide, 3950mm wheelbase), the largest articulation pin and the biggest bar axle (145mm) on offer anywhere. It's a six-step climb up to the cab.

The firm claims that making the chassis chunkier provides better weight and power distribution over uneven terrain. The drawbar extends to the centre of the tractor, which is also said to help spread the load to all four corners.

And yet, despite its size, the enormous machine is nimble. Its articulation pivot-point allows 42 degree turns (15.2m diameter turning circle on dual 800 tyres) and 13 degrees of oscillation to keep all the wheels in contact with the ground.

The whole MT900B range uses Caterpillar's 24 valve ACERT Tier III engines, delivering power through Cat's 16x4 full powershift transmission - an adapted version of the gearbox used in the construction giant's dump trucks.

But for those in Western Europe, the MT975B's size is ultimately its undoing. To get all that power down effectively on a wheeled machine, it has to run on dual wheels, making it far too wide (5.1m) for our roads.

The logical solution - aside from selling it on single wheels and an "optional" set of duals - is to put it on four tracks. It's a move which has proved successful for other machines, such as Case's Quadtrac and John Deere's H-track equipped 9020 series tractors. Challenger however, has no plans for such an adaptation.

So what's it like to drive?

Even for a novice to the Challenger brand, operating the MT975B is relatively straightforward and it is easy to forget you're driving such a big machine. Most of the controls are on a stubby joystick close to your right hand (sorry to anyone who's naturally left-handed!).

Flick the parking brake off, knock the lever into drive, bump up the throttle and away you go. Steering is light for a machine of such size, although the tight turning circle means you'll need to watch the drawbar doesn't get too close to the rear wheels for some kit.

Spool valve switches can all be found within easy reach and, on this outing, pushing forward switch one drops the 10m Horsch cultivator into work. With some 600 ponies under the bonnet itching to be let loose, unsurprisingly, the machine barely notices anything's hitched up - not necessarily a good thing if you've got less observant drivers who tangle with trees, pylons or other obstacles on a regular basis.

Notching up through the gears is made easy with the fingertip buttons on the control stick - one for up, one for down.

Challenger says that operator comfort has been made a priority within the cab and first impressions suggest they've done a reasonable job. Shared with the brand's twin-tracked crawlers, the cab feels light and roomy, with good visibility all round, although there is a distinct lack of handy cubbyholes.

Grey/black plastic trim is pretty inoffensive and climate control, a "deluxe" air-suspended seat and passenger seat are fitted as standard. It's pretty quiet too, confirmed by the official noise rating of 73dB.

Most of the information you need is displayed on the touch-screen tractor management centre within reach at the end of the armrest.

Because the MT900 range was originally designed for North American markets, rear linkage and pto equipment are not fitted as standard, but is available as an optional extra.
 

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Grrrr

Member
Too bad they won't fit down our roads!

But you couldn't turn it around in any of our fields!

And even more of our gateposts would have to go!
 

Doc

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But wouldn't it be cool to drive? Even if it did need 50 acres to turn around :pat:
 

Grrrr

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Does anyone know what sort of patterns they follow when using tractors like this one.

I can't imagine they would just go up and down because the headland turn would be so wide. Lots of backing up maybe.

Or just go round in big wide circles and then have a small(er) tractor come in to do the corners?
 

Mith

Active member
I'd assume the fields they use such a tractor in is so big that the larger headland is not an issue.
The article says it has a 15.2m dia turning circle, meaning the width of the area needed to turn in would be 7.6m + the width of the machine.

You wouldn't even get it around some of the corners in the roads around here :D
 

Jim_S

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You wouldn't even get it around some of the corners in the roads around here :D

That shouldn't be a problem with something that large. Just through the hedgerow and over the fence :yankchain:
 

California

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That shouldn't be a problem with something that large. Just through the hedgerow and over the fence :yankchain:
I love it! We need photos!!!

Realistically, those things run implements so wide that their turns are likely the same as a smaller tractor - only bigger.

Here's the first related picture I found. I'm surprised I didn't see similar field photos on the site Big Dog referenced, since what these things can pull is the real news.

Another set. In the Great Plains, particularly up into Canada, those things may run for miles before they need to turn.
 
Does anyone know what sort of patterns they follow when using tractors like this one.

I can't imagine they would just go up and down because the headland turn would be so wide. Lots of backing up maybe.

Or just go round in big wide circles and then have a small(er) tractor come in to do the corners?

Actually they do go straight up and down and have a little waste on the turns...My cousin currently has 2 of these...
http://www.challenger-ag.com/agco/Challenger/ChallengerNA/TrackedTractors/800Ag.htm

and farms 26+ square miles...in minimum 1/4 sections (thats 160 acres per 1/4 for the non-farmers...:mrgreen: ) He gets into the field turns on the navigation system and lets the tractor run the row (about 1/2 mile in length at a minmum), at the end of the row he turns the rig resets nav and does the next row...:mrgreen:
http://stellarsupport.deere.com/en_US/
 

Grrrr

Member
Yes, GPS is a nice luxury. Twas impressive that the seeding outfit we were running before christmas was accurate to 6cm. Hardly any wastage. Just the fields are too small :rolleyes:
 
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