As overall leader in the Australian truck market, Isuzu have a truck for just about every job in the Australian trucking industry, apart from extreme heavy-duty applications. Their range goes from the smallest 4.5-tonne GVM delivery truck to a 530-hp B-double prime mover with very little missing in between. However, there has been one very clear gap in the range for a considerable amount of time – and that was for a twin steer rigid suitable for work such as concrete agitator, garbage front loader, or hook lift.
The problem for Isuzu, as it is for the competition, is the requirement in Australia for a load sharing suspension on a twin steer axle to achieve GVM allowances of up to 11 tonnes per front axle. No other jurisdiction in the world specifies this kind of system as a requirement to achieve maximum GVM. As a result, manufacturers around the world have not been actively developing effective load sharing systems that comply with the Australian rules. Such systems do exist, but as an aid to truck stability and improved handling.
There is no requirement for load sharing in the Japanese domestic market and, as such, Japanese manufacturers have not invested a lot of development dollars in creating a special front suspension purely for the Australian truck market. It has been a combination of a lot of hard work on the part of Isuzu here in Australia and the importance Isuzu in Japan placed upon their Australian arm with the number one position in the truck market, which has brought about the development by Isuzu in Japan of a load sharing suspension specifically designed for our market.
“These trucks have been on our wish list for a long, long time,” Isuzu Chief Operating Officer Phil Taylor says. “The main hold up was that we wanted to get the spec just right for the Australian market. Although we have twin steers available in other global markets, they do not have load-sharing suspension. Not having one available has stopped us from competing in markets, which are now growing. With the launch of the FY range we see a lot more opportunities in the heavy duty market for us.”
Of course, once a load sharing solution has been designed, it has to be integrated into the existing Isuzu range to get the most out of technology supplied and tailor the new truck design to suit the Australian industry and their requirements. This has seen in the company using a tried and trusted approach taking different components from different models already in production to develop an all-new model using twin steer.
As a result of the work, Isuzu have announced the release of three new models in the FY Series. The FYJ 2000 and FYH 2000 are both 8 x 4 trucks with a GVM of 30 tonnes. The FYX 2500 is a 10 x 4 model designed specifically to suit the heavy agitator cab chassis market, capable of a GVM of 35 tonnes. With the various options available this means there are now nine factory built variations available from Isuzu for twin steer truck customers.
The load sharing solution Isuzu engineers in Tokyo have come up with is relatively simple but does have a high-tech element to the design. The load on the two front axle suspensions is shared by a rocker between the two front springs but includes a damper to improve performance. The damper controls the movement of the equalising rocker with the intention of giving the truck a better steering performance. This all-new design is unique to Isuzu here in Australia and has not been seen in other truck designs.
The basic design for this model became available back in 2008 when the new Isuzu F Series was launched, and more specifically, when the FX models came on stream. With the development of the FX, taking elements from F Series and from the Giga model, the basic layout became available and would form a solid platform on which to develop a twin steer system with a load sharing capability.
There are a large number of 8 x 4 trucks running on the roads in Japan, but they are built to a completely different set of specifications. The trucks are used for long distance highway freight work and run with low-profile tyres and chassis in order to maximise freight volume within the relatively tight Japanese weight and dimension rules. Therefore, the development of the FX chassis design was the first time a suitable design with the correct height and size had been available through the Isuzu manufacturing system.
The FYX 10 x 4 model simply uses the existing 8 x 4 chassis with an additional lifting tag axle fitted behind the two drive axles. The basic chassis design is able to handle the extra mass, as the individual axle weights on a 10 x 4 are actually lower than on the corresponding 8 x 4. Isuzu simply order up an 8 x 4 with a slightly longer wheelbase from Japan and the additional axle is fitted here in Australia as and when required by concrete agitator customers.
The engine being used in all these models is the Sitec Series lll 350, a six-cylinder 9.8L engine developing 345hp (257kW) at 2000rpm. This engine produces maximum torque of 1422Nm (1049ft lb) at 1400rpm. It features a variable nozzle turbocharger, high-pressure common rail fuel injection system, cooled EGR and a diesel oxidation catalyst to ensure performance and limit exhaust gas emissions.
When compared to the kind of engines currently available in these kinds of trucks on the Australian market, this specification seems just about right with the useful torque rating enabling operators to get the kind of performance they are looking for. The 9.8L engine does have the capability of being rated higher. It is available in Japan at 400hp, but at Euro 6 emission levels, and may be an option for the future.
There are three transmission options available on the new twin steer range including the Eaton RTO 11908 LL 10 speed constant mesh manual transmission, the ZF 9S 1310 TO9 speed synchro gearbox and the Allison 4430 fully automatic six speed. The choice of transmission will be application dependent with concrete agitators favouring the Allison gearbox. This is a relatively high specification for the concrete industry as most agitator buyers are normally offered 3000 Series Allison by the other truck manufacturers.
“We had to go to the 4430 Allison because of the torque available from this engine,” Isuzu Product Planning and Engineering Support Manager Colin White says. “So we are quite happy about this because of the heavy duty reliability it offers us. It is well installed in the chassis and the design is very PTO friendly, very accessible.”
For operators wishing to ensure their truck has plenty of low-down crawler gear capability, the Eaton is the obvious choice as it goes down to a low-low gear ratio of 14.56:1. For trucks travelling around in normal highway conditions or in urban delivery situations the simpler ZF nine-speed will be more than sufficient to do the job and more accessible to truck drivers with lower skill levels.
Isuzu engineers have been working hard to get as much weight out of the new model as possible. Tare is extremely important in many of the applications at which these models are aimed, especially the concrete agitator market. According to Colin White the kind of numbers possible with a standard agitator specification including a 200L fuel tank will make these new models very competitive, in terms of tare weight, when compared to the other trucks competing in this market.
The FX design has allowed Isuzu to keep the cab set relatively low to ensure ease of access in and out for the driver as well as ensuring a relatively short BBC dimension leaving potential operators plenty of room to fit different style bodies including difficult equipment like garbage front loaders.
As part of the introduction of the new models, Isuzu are also upgrading their entertainment/GPS system in the trucks. The previous all-singing, all-dancing system was one of the most advanced available on the Australian market and came as standard, but the new system introduces touchscreen capability, enabling the driver to flick through menus by simply swiping the finger across the screen. As before, the entertainment system comes as standard with an option of adding a GPS navigation system and four video camera feeds if required.
Prime Mover managed to get a feel for just how well the new models perform around the test track at Anglesea in Victoria recently. First impressions of the twin steer set-up are of a surefooted and positive steering system giving the driver the right sort of feedback from the road, without the kind of kick back which is sometimes evident in twin steer systems. Isuzu have clearly done their homework well and the load sharing rocker with its damping system have the effect of smoothing out the differences between the two front axles. Even on the larger 10 x 4 there is little evidence, even when attempting sharp turns in tight manoeuvring situations, of any conflict between the rear axles and what the front axles are trying to do.
Australia has had a long relationship with Isuzu trucks, as many in the transport industry have come to rely on the Japanese manufacturer for a solid dependable vehicle able to do the work and make money. This particular model with its new twin steer suspension system has been a long time coming. One of the reasons for the delay is the insistence by Isuzu that the specification needs be exactly right and able to cope with the worst conditions Australia can throw at it.
On the evidence of the kind of specifications available on these models, especially the 4000 Series Allison, this truck is certainly up to the job and likely to find a home in many fleets around Australia. On a first drive of the new models, the handling and directness of the steering also look like it may impress Australian truck buyers.