Thread: Towing Capacity

Originally Posted by MR LR

The GCM-GVM is your towing capacity anyway (legally)... should all be on the rego papers I'd have thought.

Towing Capacity

Originally Posted by MR LR

If I'm correct in understanding that the Perentie's have "Land Rover 110" on their compliance plate, as do the civvy 110's, then what is the worry about? If they're complied the same there should be no issue, they have a stronger chassis, so it's not like hanging 3.5T off the back is stupid...

The GCM-GVM is your towing capacity anyway (legally)... should all be on the rego papers I'd have thought.

That's the problem. They're not. The Perentie complies with a completely different set of rules than the civy 110.

An extract from ADR 62/02

12.3.2. Up to 3.5 tonnes ‘ATM’
‘Couplings’, other than those at clause 12.3.1, specifically designed for use between towing vehicles and trailers up to 3.5 tonnes ‘ATM’ when installed in the design configuration must withstand the relevant static or dynamic forces nominated in clause 12.3.2.1 or clause 12.3.2.2 when these forces are applied separately at the intended ‘Coupling’ centreline, without incurring any residual deformation that would interfere or degrade the function of the assembly or any breaks, cracks or separation of components. The static forces must be maintained for not less than 10 seconds.
12.3.2.1. Up to 3.5 tonnes ‘ATM’ – Static Testing
12.3.2.1.1. Longitudinal tension and compression of minimum (N) 1.5 x 9.81 x ‘ATM’ (kg) for the ‘ATM’ at which the ‘Coupling’ is rated; and
12.3.2.1.2. Transverse thrust of minimum (N) 0.5 x 9.81 x ‘ATM’ (kg) for the ‘ATM’ at which the ‘Coupling’ is rated; and
12.3.2.1.3. Vertical tension and compression of minimum (N) 0.5 x 9.81 x ‘ATM’ (kg) for the ‘ATM’ at which the ‘Coupling’ is rated.
12.3.2.2. Up to 3.5 tonnes ‘ATM’ – Dynamic Testing
12.3.2.2.1. Horizontal alternating force of minimum +/- 12 kN acting in a line parallel to the ground and in the longitudinal median plane of the towing vehicle for at least 2 million cycles. The frequency is not to exceed 35 Hz, and must be chosen so as not to coincide with any natural frequency of the system.

You get an automotive engineer to sign off that it conforms to that, you're laughing. Nowhere on a Perentie ADR compliance plate does it say it conforms to that ADR.

For the Perentie, there was no ADR for towing capacity in the second edition ADR's and it was a manufacturer specified thing. For the 6x6 Perentie, the manufacturers specifications were 5.6t GVM and 7.1t GCM. To get it rated for a higher GCM, it has to be tested against ADR 62/02 and probably some others. The military spec 6x6 Perentie is a different beast compared to the civilian 6x6. These diferences must be taken into account when they are comparred. For example, I believe the 4x4 the chassis rails in the Australian military 110 are much smaller than the civilian 110 in order to fit the spare wheel. That would affect the towing capacity. There may be other pertinant differences.

Originally Posted by MR LR

If I'm correct in understanding that the Perentie's have "Land Rover 110" on their compliance plate, as do the civvy 110's, then what is the worry about? If they're complied the same there should be no issue, they have a stronger chassis, so it's not like hanging 3.5T off the back is stupid...

The GCM-GVM is your towing capacity anyway (legally)... should all be on the rego papers I'd have thought.

As said they are not compliance as a land rover 110 but as a military 4x4 so as far as rms are concerned they are totally different

Originally Posted by Mick_Marsh

An extract from ADR 62/02


You get an automotive engineer to sign off that it conforms to that, you're laughing. Nowhere on a Perentie ADR compliance plate does it say it conforms to that ADR.

For the Perentie, there was no ADR for towing capacity in the second edition ADR's and it was a manufacturer specified thing. For the 6x6 Perentie, the manufacturers specifications were 5.6t GVM and 7.1t GCM. To get it rated for a higher GCM, it has to be tested against ADR 62/02 and probably some others. The military spec 6x6 Perentie is a different beast compared to the civilian 6x6. These diferences must be taken into account when they are comparred. For example, I believe the 4x4 the chassis rails in the Australian military 110 are much smaller than the civilian 110 in order to fit the spare wheel. That would affect the towing capacity. There may be other pertinant differences.

I've designed truck towbars and while the method was different, it was stress based analytical rather than deformation based physical testing, the end result for loads and safety factors appears about the same.

Which suggests there may be a stress based adr standard which could be cheaper for an engineer to approve than the physical test.

I'm pretty sure the ADR talks about approved calculations or something to that effect. Which is why I asked about the testing documentation. But that didn't go anywhere.

I enquired about getting a tow bar build about 2 years ago. There are approved engineers who can do this - was going to cost $700 for the engineer to design the bar, inspect the vehicle and inspect the bar after it was built - so the cost of the bar was extra.

No testing required as that was the reason in using the engineer. Bar the conforms with current ADRs.

Of course the tow capacity is primarily determined by the vehicle so if not available this figure would also need to be engineered.

To me the answer on the Perenties is clear - right or wrong - 1200kg in all terrain and if you want higher then get the vehicle and bar engineered and wear the expense.

Same as a 101 - 2 ton in all terrains (is capable of much more) and if I want more then I would alos have to go through the same engineering process.

Garry

Originally Posted by rathgar

I'm pretty sure the ADR talks about approved calculations or something to that effect. Which is why I asked about the testing documentation. But that didn't go anywhere.

I would say that documentation is not available to us and, if it were, would only reflect the load towing capacity of 1500kg.
That's why it would be worth getting an automotive engineer to have a look at it.

We know the tandem Haulmark trailers towed by the 6x6 Perenties were 1250kg ATM. Interestingly, the ADF had a number of trailers made by ARB that had an ATM of 2000kg.
I can only assume they were intended to be towed by the 6x6 Perenties.