Axles, Industry Issues, Powertorque Workshop

Heavier Axle Masses Required

Heavier Axle Masses Required

In the race to zero emissions, there are new challenges ahead with heavier axle masses required. Battery electric vehicles are known to be considerably heavier than the equivalent internal combustion alternative.

One state recently released a network for heavy electric vehicles with up to eight tonnes on a single steer axle and 18.5 tonnes on the tandem drive group, this is 2.5 tonnes more (26 tonnes GVM) than an equivalent non-electric prime mover operating at HML.

This is all headed to being like the steer-axle quick fix of 2006! The solution needs to be 100 per cent technical. Eight tonnes on a single tyre steer axle will require something like a 315/80R22.5 tyre at around 125 psi (850 kPa). If 850 kPa is OK for the thin chip seal then publish that as a figure as a National Standard (no secrets) and progress.

Don’t overlook the twin steer configurations, comparatively, these need to be a minimum of 12.5 tonnes (6.6 tonnes per axle), a 295/80R22.5 or a 305/70R22.5 at 850 kPa.

There are local government jurisdictions that still do not allow CML/HML, what will their position be on these mass concessions?

If a zero-emission prime mover is used in a B-double what is the implication of these mass increases on axle spacing mass schedule – and let’s not continue to play games (like VicRoads do with structures – when the group axle spacing is 1180mm rather than 1200mm).

There are technical solutions to the rubber on the road issues, but where do bridges and culverts stand? Will there be a minimum clear space between a single steer axle and the first axle of the prime mover tandem group?

Image: Prime Creative Media


Recently there has been much hype about emissions of larger SUVs and tradesman utilities and emission standards. Australia is not the architect of any emission standards the ADR 80 suite of emission standards are, in the main, an adaption of Euro or other international standards.

None of these vehicles are manufactured in Australian and no manufacturer develops an engine in Australia specifically for Australia.

There is much talk about battery electric vehicles, but it seems technical convenience isn’t providing answers for the hard questions.

  • What is the source of power to charge these vehicles coming from, especially at night if it’s not coal/gas?
  • What happens to the out of service batteries?

The recharge for BEVs will need to come from the grid. Regional areas already pay more for access to the power grid and supply than do metropolitan suburbs. So once again, the regional areas will pay for the city centric ideals.

Solar doesn’t produce power at night and wind generators don’t produce power in calm conditions. The ACT promotes renewable energy, the ACT 26 turbine wind farm can reportedly generate 390 GWh of clean energy per year.

In 2021 Australia reportedly generated 265,000 GWh of electricity, of which 71.7 per cent was being generated from coal (52.9 per cent) and natural gas (18.8 per cent), that’s 190,000 GWh, in simple terms Australia would require 500 ACT wind turbine farms to replace coal/gas. However, none of this addresses the issues of suitable grid distribution in getting the electricity to the transport recharge site.

To the end of 2020, the Australian rigid and articulated vehicle fleet reportedly annual consumption was 7,465 megalitres of diesel. Assuming an ICE diesel engine thermal efficiency of 40 per cent this equates to an actual transport task energy equivalent to 2,986 megalitres of diesel.

To substitute transport diesel with electricity, there is a need for a further equivalent of 82 ACT wind farms; and, much of this energy requirement will be at night, hence solar will be of little benefit, thus the grid will be very dependent on wind generators. With this zero-emission wind power generation, when will the promoters be specific on what happens to the life expired wind turbine blades?


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