Even with increased performance promised by the latest agricultural tractor tyres, tractor manufacturers and users are looking to tracks to provide an alternative solution to optimise traction and reduce compaction, particularly for field work. David Williams visited a Norfolk farm where the latest entrant to the half-track tractor market has been working this autumn.
Norfolk farming business NE Salmon moved to Great Fransham near Dereham in 1955, and has used tracked tractors for all cultivations since a Doe Triple-D was replaced by the family’s first steel-tracked machine. “My grandfather and father expanded the farm from just 100ha, preferring tracked tractors to wheeled alternatives as they coped better with our challenging soils and allowed them to get the work done,” explains Ed Salmon. “When the first rubber-tracked Track Marshall became available offering extra convenience and ease of transport, they moved away from steel tracks, and we have remained with rubber tracks since, for all cultivations and drilling. In recent years we have also adopted a controlled traffic farming regime (CTF), where practical.”
Maintaining soil condition
Just under 2,000ha is farmed which is a mix of owned and contract-farmed land, and for more than 40 years a 10-year rotation has been practised. This is appreciated by Ed as he has inherited soils which are in good condition and black-grass populations remain low, helping the farm maintain a strong reputation as a high quality, clean seed producer.
Crops include oilseed rape, winter wheat, winter barley, spring barley, spring beans, sugar beet, maize, herbage seed, potatoes and vining peas. The maize is for a local digester for which Ed and his team carry out pre-drilling cultivations and the potatoes are grown within the rotation on lighter land rented to a local farmer.
Soil types range from sandy with flint, to chalky boulder clay and vary considerably within individual fields, creating a challenge for management. The farm’s Vaderstad drill is fitted with SeedEye which counts every seed and regulates drilling rates to maintain intended populations for an area, and variable rate seeding is practised, except for seed crops which are usually drilled by weight.
Although CTF is used, Ed stresses that he remains flexible in his approach. “We are still evaluating its benefits,” he explains. “It’s harvest CTF currently, and the combine, chaser wagon and bale chasers all stick to the tramlines. We spread a lot of muck too, so the spreaders are also compatible with our tramline spacing.
Tracks and wheels
The current farm fleet includes three main wheeled tractors used primarily for transport tasks, and three twin-track crawlers; two of which carry out most of the field work while an older Claas 95E has been retained as a reserve and carries out lighter duties. However, while the crawlers help protect the soil structure and relieve compaction, a big disadvantage of the skid-steer turning action are ridges created during headland turns which, if left, have an adverse affect on subsequent field work through the rest of the growing season.
Ed has considered alternative tracked systems in recent years, but found nothing suitable. “We trialled after-market track units to replace wheels on conventional tractors, but they wouldn’t follow the ground contours well enough. We also tried some manufacturer-produced half-track models but it was obvious that the weight was concentrated on a small ground area, so compaction wasn’t much different to a wheeled tractor.
As well as the elderly Claas crawler, the farm also runs a modern Claas Lexion 780 combine and a Scorpion handler and Ed said the local dealer, Manns at Thursford, provides excellent back-up. “The team at Manns knew we were looking at tracked tractor options and asked if we would be interested in trying a new half-track type system which they felt would provide a solution. Our combine has Claas tracks and we can’t fault them; we know other manufacturers also fit Claas tracks to products such as potato harvesters and we believe they are the best on the market.”
A new Axion 960TT with half-tracks was delivered to the farm in August, just in time for autumn cultivations and drilling.
“It is just what we have been waiting for,” confirms Ed. “We put it on our 7f semi-mounted plough and we couldn’t fault it. Then, as soon as we started drilling, it was used on our Vaderstad 8m drill and it’s excellent. Having this much power in this configuration makes it incredibly versatile so we will be selling one of our twin-track crawlers and using the Axion for ploughing, cultivations and drilling.”
Because the new Axion TT is the farm’s first Claas tractor, an Axion 960 wheeled version was loaned to the farm until the new model arrived. Main machinery operator Daniel Edwards says he was sceptical at first. “I hadn’t used a Claas tractor previously so didn’t know what to expect but as soon as I drove it for the first time I was impressed. It performed well and the comfort amazed me. The cab was excellent, I liked the controls – including the CMotion joystick which is the same as our combine. The new Cebis display is easy to use – I couldn’t fault it.”
Apart from the wheels, the farm’s new TT version is almost identical. “If anything, now I have used the tracked version I prefer it,” comments Daniel. “It’s quiet, and just as comfortable even on the road. It’s very stable, the tracks feel planted to the ground and there is none of the swaying which occurs with large tyres.”
The new Axion 900TT tracked variant is available in two models – the 445hp 960 and the 355hp 930. The new Claas track system is the first with full suspension and the company says it was designed based on 30 years’ track experience with Lexion combines.
For the tractor application where higher torque loading is a factor, the new tracks have a larger spoked drive wheel with rubber blocks to aid self-cleaning. Higher track tension prevents slip, and improves pressure distribution.
The new track suspension not only increases traction capability, but with front axle and cab suspension it provides unprecedented comfort for the user, claims Claas.
CMatic infinitely variable transmission is standard, and drive is through a cardan shaft to the track units. The wheeled tractors’ trumpet housings are replaced by ‘saxophone’ housings to bridge the height and length difference.
The new Axion Terra Trac units can pivot from +8 to -15 degrees, maintaining optimum ground contact over uneven surfaces.
Rubber track options include 635, 735 and 890mm, and all maintain a road transport width below 3m. The widest 890mm tracks have a 3.87m2 ground contact area; 35 per cent more than a 900/60R42 tyre. Claas claims this results in 50 per cent less ground pressure than the tyre, with15 per cent greater traction capability.
Performance during field turns is improved by an intelligent steering system. Below 12kph the brakes of the inner track are biased and the operator can select the degree of assistance needed in three levels. As a result, scuffing in turns is reduced for steering performance similar to a wheeled tractor.
The new Axion TT models also feature height adjustment. The operator can select low, medium or high positions for the track units allowing the optimum height to be set for different implements, and for tasks such as baling the tractor can be raised to clear the swath.
Impressed from the start
The track’s performance has impressed Ed from the start. “One thing I really like is its ability to follow the ground contours. Along the full track length it’s obvious that the weight is evenly applied as the tracks and rollers mould around every undulation. Its ability to put the power to the ground is excellent and even while ploughing the slip indicator didn’t move from zero. It’s just as comfortable on the road as it is in the field and at almost 50kph it doesn’t ‘nod’ as most large wheel tractors would and feels far more stable. It’s easy to forget that it’s on rubber tracks rather than wheels.”
Ed and Daniel have also been pleased with the improved headland turn performance and, in particular, the lack of ridging during turns. “Previously we drilled the main field, then re-cultivated headlands before drilling, otherwise we would be thrown out of our seat each time when the field was sprayed later in the season,” adds Daniel. “Even turning on full lock, the ridges left by the new Axion TT are no larger than from wheeled tractors, so we save time and can get the field finished without waiting for a second tractor and operator. Obviously a twin-track crawler can turn on the spot, but for practical field work the Claas tractor turns just as tight.
“I think the drive system is a key part of its success,” continues Ed. “Unlike conventional crawlers which disconnect the drive to one track while turning, the Claas design uses electronic power distribution maintaining drive through both tracks during the turn. This helps maintain traction and reduces slip and scuffing.”
Farmers Guide visited the farm in early September when the Axion TT was working with the 8m Vaderstad drill. The previous crop was a two-year grass ley and subsequent cultivations and exceptionally dry weather had created a cloddy seedbed on heavy ground at one end of the
field and a loose, fine tilth in lighter sandy soil at the other.
At both ends it was easy to see why Ed was so pleased with the new tractor’s turning performance. Despite turning back on itself for each bout there was no sign of the ruts and ridging which had proved an issue with the twin-track machines.
In the cab with a target speed of 12kph the ride was excellent and noise levels were low, with the engine and transmission constantly adjusting for optimum efficiency. Typical engine speed was 1,250–1,350rpm and even when accelerating after each headland turn the slip indicator remained at zero.
With the new Axion proving immediately successful, Ed is already considering further Claas products for the future, and a demonstration Xerion 5000 had been trialled the week before Farmers Guide’s visit. “Moving to CTF provides new opportunities and the big Xerion’s power means we could pull a wider cultivator and remain in our wheelings.
“Mann’s local depot is nearby and our sales representative, Thomas English looks after us well, having taken over from Paul Peachment who was also excellent. We have Claas UK’s Saxham headquarters under an hour away and tractor brand manager Steffan Kurtz has also been keen to work with us and the new Axion TT. The product range is good and the brand is a logical choice.”