Truck manufacturers seem to have discovered a new niche in the market, the lifting pusher axle is on the rise and is appearing in a Diesel test drive for the third time in eight months. This time Diesel News runs the Hino GH through its paces.
It is is difficult to gauge why the last year or so has seen more pusher axles on rigid trucks available for test than in the rest of the century. There are a number of possible reasons, some obvious and some not so plausible. The one fact we can be sure of though, pusher axles have now become a thing.
Is there pressure out there in the truck market for a pusher axle? Are truck buyers wandering into dealerships and asking for a 6×2 or 8×2 with a pusher? The answer to these questions is probably no, but there are lots of operators in the distribution sphere who are looking to improve productivity and flexibility within their fleets. Costs are a big factor so reduced fuel consumption and lower tyre wear are attractive benefits.
Utilisation is also on the minds of truck buyers. In a distribution scenario the route may need a four wheeler one day and a six wheeler the next. In another scenario a truck may go out with a light load for multi-drop delivery, but return to base with a heavier load requiring three axles.
There is a third possibility. After a crazy ten years from 2002 to 2012 in which engine emission rule changes meant new engines and technologies had to be engineered into every range of trucks every few years, we are now looking at an hiatus, which may stretch out until 2027 before the ADR 80/04 rules come into play. This has given the engineering teams the time to play with other gadgets, like lifting axles.
The model Diesel is taking out on the road this time is the Hino GH 1832, but this is not an 18 tonne GVM truck. By fitting a lifting pusher axle the GVM goes up to the mid twenties. This is not an issue, this 320 hp nine litre engine has got power and torque to burn, making it able to cope at max GVM with relative ease.
The Hino A09C-US engine puts out 320hp (235kW) of power, reaching its maximum power at 1800rpm. Maximum torque, at 1275Nm (940 ft lb) is available all the way from 1000rpm up to 1850rpm. The engine uses common rail fuel injection and SCR to achieve this level of performance and keep inside the confines of the ADR 80/03 exhaust emission limits.
The lifting system or the pusher axle works in the same way to many a similar set-up with the truck acting as a 4×2 with the axle raised until it senses over six tonnes mass on the drive. The axle is then lowered to help carry the mass. Six tonnes is the level set by the regulations, but the reason for this is difficult to fathom. A normal 4×2 can operate with the mass on the rear axle up to at least nine tonnes, go figure.
A more rational approach to the way these regulations are laid out would introduce even more flexibility into the equation. If the second rear axle didn’t drop until nearer the nine tonne limit, the truck operator would have an effective 4×2 which would only increase fuel consumption and tyre wear when running at over 4×2 GVM limits.