Isuzu Twin Steer

The Isuzu brand has not been the number one selling brand in Australia since 1989 for no reason – it has worked very hard to ensure it had a line-up precisely tuned to the requirements of the Australian truck buyer. The company’s latest entrant to the domestic market – a twin steer model – is supposed to build on that heritage.

The concrete agitator market has recently developed a preference for the 8×4 set up, as it can provide the ability to carry more payload in a similar sized envelope to the 6×4 configuration favoured in the past. That’s why the FYH 2000 and FYJ 2000 come in 8×4 configuration, while the FYX 2500 will be a 10×4.

While Isuzu did sell some 6×4 trucks into the concrete business, it has never had a great deal of penetration into that market segment, so the new range is somewhat of a second try. There are very few market segments into which Isuzu has not made serious headway, and the decision to target the concrete business was taken many years ago.

It’s fair to say that getting a Japanese built 8×4 onto the Australian market in a specification to precisely suit the needs of operators moving concrete or garbage is a long and arduous process – and as a ‘newcomer’ to that niche, Isuzu had to get all specification right to compete against Iveco, Freightliner and Mack, who have been honing their product for a long time in the Australian market.

On the other hand, Japanese truck manufacturers build a lot of 8×4 vehicles, as they are extremely popular on the domestic market in Japan. Unfortunately, the design of Japanese trucks is very different to the kind of vehicle concrete companies in Australia are used to – not to mention the unique requirement for a load sharing front suspension on twin steer axles operated in Australia. This regulation is unique in the world, making the design of twin steer trucks difficult for many manufacturers coming to Australia.

Another problem for Isuzu before returning to the agitator game was the economics side of the concrete industry, which is all about keeping tare weight down to the last kilogram. Japanese domestic truck buyers are not as deeply concerned about tare weight, so the core design of many Isuzu trucks is based around the preferences of the Japanese market.

As a result, the Isuzu engineers not only had to turn the front suspension into a load sharing setup, but also take as much weight out of the basic cab chassis as possible. After several years of to-ing and fro-ing between Isuzu’s Melbourne headquarters and those in Tokyo, the first 8×4 and 10×4 Isuzu trucks made their appearance at the end of 2012. Since then, the first production models have made their way to Australia – and Prime Mover was the first magazine to get a chance to test drive the new models on an Australian road.

To get a first impression of the new agitator generation, the FYJ 2000 was taken around the city streets of Brisbane to see just how well the new design would suit Australian conditions and Australian drivers – both of whom can be difficult. For test purposes, the agitator was loaded with sand to replicate the kind of freight and mass it will have to face in everyday life.

One of the most important aspects of a truck in this market segment is ‘ease of use’ to avoid any distractions from the actual job at hand. And, simply climbing into the truck for the first time reveals how serious Isuzu’s engineering team has taken the brief. Simply open the door, grab the long handle on the A-pillar and climb up the well spaced steps into the FX cabin, sit down in the Isri 6860 air suspension seat with integrated seat belt and start working.

An Allison transmission is virtually standard for the concrete industry and this new Isuzu uses the 4430 model. The specification had to go to the 4000 series instead of the 3000 series used in many agitators, because the torque output is higher than the parameters set by Allison for the smaller transmission. Allison would normally say 360 hp is the limit for the 3000 range – but with such a torquey engine the specification has to be a 4000.

In fact, Isuzu’s Sitec 350 engine has a displacement of 9.8 L and puts out 345 hp (257 kW) at 2000 rpm. It delivers 1422 Nm (1049 ft lb) of torque – and it is this figure which gives the truck such a good feel in the stop/start environment of busy traffic and travelling from concrete plant to building site. Couple this engine with a well set up Allison installation, and every driver will exactly what they want – a truck which will go when required and stop when required, getting from A to B in the fastest time and with the least amount of fuss.

Running around in a fully loaded truck, it never feels like it has to work too hard. The combination of plenty of torque and a fully automatic transmission make driver’s life easy. He or she simply has to concentrate on whether to be using the go pedal or the stop pedal. It is possible to focus on the busy traffic and manoeuvring the truck into position without having to worry about which gear is needed.

The six-speed Allison box seems very well set up and the ratios feel ‘just right’. At highway speed, on cruise control at 100 km/h, the tachometer is only reading 1600 rpm, the same as a long-distance line haul truck. Lower down, the combination of well judged ratios and a torque converter sees the truck able to take off, fully loaded, on a steep grade in Paddington without any juddering or bucking. It simply slowly applies the increased torque to get the truck moving. It will continue smoothly up a steep grade and the only thing to cause any concern is backing off on the accelerator on the steepest part of the climb. Such behaviour is sending confused signals and may cause the truck to stutter.

Steering is also light and simple – in fact, this is the demonstration of a well set up twin steering and suspension system. There is just enough feedback from the front wheels to the driver's hand on the steering wheel, but no unnecessary resistance or kicking for the driver. The relatively simple mechanism – using a mechanical equaliser and shock absorbers – gets Isuzu over the load sharing line, without compromising simplicity.

When it comes to deceleration, our test model does not use the combination of exhaust brake and transmission to retard the truck as well as some of its competitors, though. It would seem the exhaust brake is not precise enough to really get the most out of the increase in rpm, which is caused by the down change initiated when the exhaust brake is turned on at the same time as the right foot is taken off the accelerator. After all, this truck is running at a relatively high mass and it is a lot to expect of a simple exhaust brake. The service brakes will do the job very well, and concrete work will always be hard on truck brakes.

This FX cabin is also fit for purpose. It is one of the most recently introduced cabins from Isuzu, so it is a comfortable and well-designed environment. The double 'wave' shape of the dashboard on the driver's side looks modern and is effective. Isuzu can also boast an entertainment system taking up two DIN slots and a climate control. Fitting this cabin is also preferable to the Giga alternative, is not only ageing but probably also heavier.

The gearbox controller option used on this model is the pushbutton Allison controller. It is mounted on a pyramid-like box in the position where the gearstick would normally be. It appears to be larger than it needs to be and could compromise cross cab access, but it probably not an issue as access will be compromised by controllers for the concrete agitating equipment anyway. Also, there is no space on the dashboard where the controller could be easily fitted and remain accessible to the driver's left hand.

From the driver's seat, visibility is excellent. The windows are set low enough, about the height of the driver's knee, to allow an all-round view close to the cabin. The reliable Isuzu rear view mirrors with the main mirror and spotter included in a single unit that is controllable from inside the cabin, are still as good now as they were when Isuzu first started using them. We are still waiting for them to update the style of the controllers for these mirrors, however. This model also includes an extra mirror fitted above the windscreen on the passenger side, giving the driver a clear view of exactly what is in front of the cabin, right up to the bumper.

As a result, it is fair to say that Isuzu came up with a truck specification very close to the requirements of the target market, ticking as many of the boxes as possible. This has been the Isuzu way for many years and, yet again, the company has taken its time to thoroughly research exactly what the concrete industry requires to come up with a vehicle that will do the job as well as any of its competitors.

The issues connected to the introduction of a twin steer – something Isuzu has not sold here before – could create some difficulties for the organisation. But from the evidence of our first test drive, it would appear issues will be far and few. The feel of the steering and the way the truck manoeuvres suggest Isuzu has got the steering geometry precisely right. The ride, out on the highway, suggested the suspension options are also well chosen as well. The proof will now be in the eating, when the trucks are out there and being worked hard by the concrete companies.

 

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