7 November 1998

TRACTORS TRADE ON COMFORT

Tractor manufacturers have launched more new models and high-tech features over the past 12 months than for many a year. In the run-up to the Royal Smithfield Show, Peter Hill provides a timely round-up of the key newcomers.

WITH drivers having a bigger say than ever in the choice of tractor they drive – and more growers taking their turn in the driving seat – operator comfort has become a key factor in tempting buyers to new tractor models.

JCBs Fastrac, with its all-round axle suspension, has no doubt had some influence here; after all, many Fastracs are bought as much for their in-field comfort as for any other advantages they may offer.

In response, manufacturers of more conventional tractors have sought ways of reducing the effect of driving a tractor with rigid rear axle over rough surfaces – be it in the field or on the road. In addition to fitting air suspension seats, they have so far come up with three solutions:

&#8226 hydraulic lift linkage damping;

&#8226 cab suspension;

&#8226 front axle suspension.

Operators can add a fourth measure – fitting larger volume tyres. Bigger tyres, holding more air, can support the same load at lower inflation pressures. And squashier tyres are more effective at absorbing bumps rather than passing them on to the driver in the seat. It can make a real difference to driver comfort.

The benefit of hydraulic linkage lift damping is that it reduces the secondary effects of passing over a bump at speed with a mounted implement. Similarly, front axle suspension does much the same job for the front end of the tractor, while also improving steering and, to some extent, braking stability.

Cab suspension, on the other hand, seeks to isolate the driver from chassis movements more effectively than a suspended seat alone.

Renault has long advocated this approach and drivers who have experienced it certainly vouch for the effectiveness of its Hydrostable design. This a fairly sophisticated arrangement, with coil springs and dampers at each corner connected by rods to arrest sideways and fore/aft movement.

It produces a curious sensation as cab and tractor bodywork move in different directions, but that has not deterred buyers. In 1996, before the current Ares range was introduced, Hydrostable cab-equipped tractors accounted for 7% of total Renault sales – including models on which it is not available. Last year, helped by the Ares launch early in the year, that proportion rose to 23%.

In the first eight months of this year, the figure climbed to 40%, with more than 80% of Ares tractors Hydrostable-equipped. Little wonder, then, that this cab is a standard feature of Renaults latest – and most powerful – Ares model, the 185hp 735RZ.

Deutz-Fahr is also focusing on cab suspension (in addition to sprung front axles), though with a simpler design that comes in mechanical and pneumatic versions on different Agrotron models, both with lateral rods to stop sideways sway.

Suspension

On both types, the front of the cab is secured more or less conventionally using rubber blocks. But at the back, the cab rides on either coil spring/telescopic damper units or pneumatic springs – the latter, more sophisticated system is reserved at present for the newly-introduced 230hp and 260hp Agrotrons.

Pneumatic cab suspension is reckoned to be more responsive than a purely mechanical system and on the Agrotron is load sensitive to provide the same degree of comfort whether the driver rides alone or with passenger.

Front suspension shows a greater diversity of designs – from the Carraro independent wishbone layout due to be introduced on six-cylinder Steyr and Case-IH CS tractors to John Deeres Triple Link rigid axle layout launched this year.

These join hydraulic lock-out designs from Fendt and Deutz-Fahr. Unusually, Deeres system is designed to operate at all times without a lock-out facility, giving the benefits of a front end that gives over rough ground in all operating situations.

Adding diversity is the new Aires front suspension option for Mega-series Valmet tractors, which features compressor-boosted pneumatic springing rather than the gas accumulator-damped hydraulic systems favoured by other makers.

CASE-IH

HEAVIER and more powerful versions of the Maxxum MX fill out the Case-IH range with rated outputs of 151hp and 166hp climbing to 161hp and 177hp under additional load. A 150mm longer wheelbase improves weight distribution with heavy implements and the transmission, offering four powershift speeds in four ranges, has bigger gears and shafts to cope with the extra power and torque.

Clutch packs and other key parts are also uprated, along with hydraulics output.

At the other end of the scale, the C series Maxxum MX tractors provide higher-spec alternatives to the CX models of similar output that Case also introduced this year. Power outputs are 84hp, 90hp and 102hp, with Perkins-built load bearing engine installations in contrast to the frame structure of the larger Maxxums.

Compared with the CX models, the newcomers have a more versatile four-speed thumb switch-operated powershift instead of simpler synchroshift gearboxes; they can lift quite a bit more on the three-point linkage; and the have bigger output hydraulics from a variable rather than fixed output pump.

The CX range itself marks a significant advance over the 3200/4200 series, with Perkins engines giving 50hp to 100hp outputs at tidy 10hp increments, lower noise levels, more torque, better power characteristics, and greater economy.

A newly-engineered gearbox matches forward-reverse speeds for easier shuttling, and there is electronic linkage operation with sensed electronic draft control.

DEUTZ-FAHR

THE Deutz-Fahr Agrotron range has been further extended with 230hp and 260hp giants designed for high output tillage operations.

Powered by Deutz six-cylinder liquid cooled motors, the tractors can operate at up to 14t and run on big diameter front and rear tyres – 710/70 x 42 covers are fitted at the rear.

Sitting snug in the familiar Agrotron cab, the driver gets a panoramic view of both the implement hes working and way across the plains. And he should be more comfortable than ever once under way thanks to hydro-mechanical front axle suspension and pneumatic, load-sensing cab suspension – the first of its type on a farm tractor.

Beneath the cab floor, a ZF 7300 gearbox and transaxle assembly (as used on the Fendt 800-series) links engine and wheels, with a fluid turbo clutch protecting the conventional clutch, gearbox and engine from shock overloads, and preventing engine stalls.

The gearbox provides semi-powershift, with four joystick selected powershift speeds in each of six manually-selected range gears. Forward/reverse is by a pre-select mechanical shuttle.

Up front, ZFs biggest tractor drive axle is used, with locking diff and automatic driveline management controlling four-wheel drive and diff engagement.

At the other end of the Deutz-Fahr line-up are four Agroplus models taking the line to 100hp as lighter and smaller alternatives to the Agrotron.

Specifications include a choice of synchromesh or three-speed powershift gearboxes, and mechanical or electronic linkage draft control. Buyers can also opt for two joystick controls for external hydraulics.

NEW HOLLAND

FRESH styling and a new title highlight engine and cab interior updates for the New Holland Series 40 tractor range. There are three TS tractors, all powered by four-cylinder Powerstar engines tuned to meet emissions requirements. Power outputs are down a touch on their predecessors but this is compensated by improved power and torque characteristics that should help maintain performance. Rated outputs are a tidy 80hp, 90hp and 100hp.

Compared with the New Holland L/35 models of similar power, the TS tractors have electronic rather than mechanical draft control, more weight, more hydraulic power and the option of a four-speed powershift transmission. Larger rams give the tractors more lift than their predecessors and more front end weights can be fitted to keep things balanced.

Better quality materials, new mouldings and a more generously proportioned seat greet the TS driver, along with standard air conditioning and seat air suspension.

RENAULT

AT 185hp, Renaults Ares 735RZ now tops the French manufacturers range – until further newcomers, likely up to 250hp, are unveiled next year.

Powered by an intercooled turbo Deere engine, the big tractor has load-sensing hydraulics – for the first time from Renault – with individual valve flow control and lever-release couplers that allow pipes to be plugged in or pulled out regardless of system pressure.

The hydraulic lift will handle 600kg more than the 145hp and 165hp Ares models – capacities are 11,330kg maximum, 8,050kg to full height – with electronic operation standard, and add-on options of traction control and a timer system for automatic operation of semi-mounted ploughs.

Quadrishift transmission gives a total of 32 speeds in either direction, four-speed push-button powershift and synchromesh manual shuttle, while front and rear axles are a grade up on the other two Ares 700-series tractors.

Further down the Ares range, revisions to three-point linkage geometry (including a higher upper top link position) give up to 6% more lift capacity and greater clearance beneath mounted implements, while Revershift offers clutchless forward/reverse changes for the first time on 95hp to 130hp models.

Two hydraulic clutches transfer engine torque to planetary gears which cause the gearbox output shaft to turn in the opposite direction, ensuring smooth transitions from one direction to the other. In the Ceres range, larger hydraulic cylinders contribute extra lift capacity on 75hp and 85hp models, with revised valves giving faster operating speeds.

ZETOR

MORE modern appearance and a spacious, glassy cab heralds significant mechanical improvements on the Zetor UR1 Super, which include revamped engines, wet disc brakes, an optional fast transmission, and a limited slip front differential.

There are four models at 60hp, 70hp, 75hp and 84hp, all with two- or four-wheel drive, other than the four-wheel drive only 84hp version.

Improved torque and power characteristics are claimed for the engines, there is more fuel capacity and although transmissions are improved internally in detail, the most obvious change is gear selector levers positioned either side of the drivers seat.

Lift linkage capacity rises to 4,000kg with the help of two assister rams, and driver accommodation is transformed by the new cab, particularly in terms of all-round visibility.

JCB

UPRATED transmission components and three-speed powershift, with mode-selectable automatic gear changing feature among Fastrac upgrades.

The 2000-series field tractors, with 50kph transmissions, now stretch from 115hp to 148hp while the road models with 65kph gearing run to 150hp and 170hp. Revised front suspension significantly improves the bigger tractors turning ability.

Moreover, all Fastracs get an extra 18 forward gears thanks to a three-speed powershift that offers auto gear changes with different operating strategies for different tasks, as well as an opportunity for the driver to programme his own gear-change parameters.

Other drivetrain changes bolster the Fastracs durability with heavier duty rear differential pinions and bearings, tougher axle drive shafts and a more positive prop shaft/diff coupling. The 150hp and 170hp machines also get a bigger front axle and locking differential.

In the cab, electronic instrumentation brings a host of new functions – from output calculations to real-time fuel consumption from which tank contents and remaining work time is calculated and displayed. Automatic wheelslip control also comes with this package.

FENDT

HAVING successfully tested the water with the 260hp Favorit 926 Vario, Fendt has extended its hydro-mechanical transmission to three more models of 170hp, 200hp and 230hp. And there is more to come, with the imminent UK unveiling of the 700-series tractors at 140hp and 160hp which not only feature the Vario transmission but frame-type construction and new 24-valve Deutz engines.

Vario combines mechanical and hydraulic drive in a progressive manner to give infinitely variable speed control with minimal loss of power transmission efficiency.

Programmable features enable the driver to use the system in different ways – to achieve constant speed or give priority to power or economy. The 900-series Vario tractors are based on the Favorit 800-series models, so hydraulic lift capacity is the same at 9,180kg, the electronic control system for the hydraulics is the same, and the two designs share the same spring suspended cab.

JOHN DEERE

USEFUL increases in power from new engines, a semi-automatic gearbox and front axle suspension are highlights of the 6010 Series tractors from Deere.

The 4.5 and 6.8-litre PowerTech engines used in the 6010 Series meet current and forthcoming emissions legislation, with high torque output and rising power characteristics aimed at improving performance and productivity. With the AutoQuad transmission, the engines have electronic governors which tend to react more effectively to changing load and provide scope for using a cruise-control feature that will more accurately maintain a desired operating speed.

Four-cylinder models range from the 80hp 6110 to the 105hp 6410 – both gaining 5hp in rated output – while six-cylinder versions go from the 105hp 6510 to the 135hp 6910.

Automatic powershift changes are available on 100hp models upwards, leaving the driver to concentrate on steering and implement control.

The AutoQuad transmission deploys 24 speeds in all, with clutchless powershuttle for forward/reverse selections – uniquely available with a selector to the right of the driver or as a steering column stalk.

VALMET

EXTRA gears, uprated hydraulics and a higher-spec cab feature on Valtras four-model Valmet M100 series.

They use the same three- and four-cylinder Valmet engines, delivering 60hp to 90hp, mounted well forward in the tractor to promote good traction when pulling draft implements and extra stability when carrying loads on the three-point linkage.

But the engines are revised for improved torque and fuel economy, and can be coupled to a new 16 x 8 speed gearbox giving extra speeds and a push-button splitter.

A beefed-up back-end with stronger lift linkage components gives buyers the option of 3.3t lift capacity in place of the standard 2.5t specification, with Autocontrol electronic linkage management standard on the 70hp and 90hp tractors.

A flat-deck cab, introduced originally on the Valmet 865, offers better visibility and a neater interior.

MASSEY FERGUSON

FEATURING full powershift for the first time on a European Massey Ferguson tractor, the MF8170 tops out the companys range with a 230hp Valmet engine. This six-cylinder inter-cooled turbo engine delivers power bulge characteristics that raises output to 242hp as revs are pulled back under load, and maximum torque lugging away at only 1400rpm.

The Funk gearbox is operated by a short control lever mounted on the drivers seat armrest, and takes light taps in either direction to move up or down through the 18 forward speeds. Programmable features are designed to make the tractor easier to drive and more productive.

An all-new back end for this tractor includes external lift rams giving 10t lift capacity for big mounted implements; and Kleber has produced a new tyre for the machine which, as a 650/85R38, uses its large diameter to produce a big contact patch, instead of relying on section width.

DISTRIBUTION

NEW distribution arrangements have been put in place for several tractor marques this year.

Steyr, the Austrian manufacturer owned by Case, has switched to a new business – Bonhill Marketing – formed from the previous Fendt importer, while the Fendt range itself was brought under AGCOs wing, with some Massey Ferguson dealers appointed to take on the range.

Most recently, the Italian Landini company has switched to Zetor importer Motokov with the hope of raising its profile and sales in Britain.