Pony
Senior Member
I was going to post the question in the overload of the day thread, but then figured I'd just start a new one.
Having a few beers with some mates and started talking about what we call GVM's (Gross Vehicle Mass) here in Australia and how they relate to the real world capacity of the truck.
Now we were talking real trucks, air brakes, 11R 22.5 tyres etc, but the conversation can go to smaller vehicles as well.
I'll stick with with the details of my new truck as it's fresh in my mind, but question can apply to any vehicle.
Truck is bogie drive, single steer, flat bed, 400hp.
Australian?, Queensland for sure, road limit mass for 3 axle truck as above is 22,500kg.
GVM for my truck is 24,000kg.
Front axle 6,500kg.
Rear axle group 21,600kg.
Rear suspension group 18,000kg.
295/80 22.5 steers and 11R 22.5 drives.
Truck is speed limited as required to 100kph.
The argument we were having was around the 'safety factor built into the mass limits. My theory was that speed is a factor in determining these limits.
My peanut brain says that a truck weight 22,500kg going 100kph hitting a bump in the road produces 'x' amount of stress on all components. However same truck hitting same bump at 120kph will produce 'x+?' stress. Therefore same/same at 80kph will produce 'x-?'.
Therefore if my truck were speed limited to 80kph would the GVM be, say 28,000kg?
Following on, speed limited to 40kph would the GVM be 35,000/40,000kg?
Again, my mind says speed would increase stress exponentially.
Obviously there comes a point where static load is simply to high and permanent deformation of components occurs.
Getting back to the Overload thread, my idea is that it mostly reverts back to speed, more specifically the ability to stop the overloaded vehicle safely. So if the speed were taken out of the equation, at what point does it become unsafe?
Most of the photos in that thread are of pick ups towing overloaded trailers, steer tyres very light, limited braking, lethal accident waiting to happen at highway speeds.
How about on your own property at walking pace, I'm assuming that none of the pictured pick ups/trailers had permanent deformation from the loads, therefore would that be ok?
Long rambling post I realise, but just wondering what safety factor is built into components?
Having a few beers with some mates and started talking about what we call GVM's (Gross Vehicle Mass) here in Australia and how they relate to the real world capacity of the truck.
Now we were talking real trucks, air brakes, 11R 22.5 tyres etc, but the conversation can go to smaller vehicles as well.
I'll stick with with the details of my new truck as it's fresh in my mind, but question can apply to any vehicle.
Truck is bogie drive, single steer, flat bed, 400hp.
Australian?, Queensland for sure, road limit mass for 3 axle truck as above is 22,500kg.
GVM for my truck is 24,000kg.
Front axle 6,500kg.
Rear axle group 21,600kg.
Rear suspension group 18,000kg.
295/80 22.5 steers and 11R 22.5 drives.
Truck is speed limited as required to 100kph.
The argument we were having was around the 'safety factor built into the mass limits. My theory was that speed is a factor in determining these limits.
My peanut brain says that a truck weight 22,500kg going 100kph hitting a bump in the road produces 'x' amount of stress on all components. However same truck hitting same bump at 120kph will produce 'x+?' stress. Therefore same/same at 80kph will produce 'x-?'.
Therefore if my truck were speed limited to 80kph would the GVM be, say 28,000kg?
Following on, speed limited to 40kph would the GVM be 35,000/40,000kg?
Again, my mind says speed would increase stress exponentially.
Obviously there comes a point where static load is simply to high and permanent deformation of components occurs.
Getting back to the Overload thread, my idea is that it mostly reverts back to speed, more specifically the ability to stop the overloaded vehicle safely. So if the speed were taken out of the equation, at what point does it become unsafe?
Most of the photos in that thread are of pick ups towing overloaded trailers, steer tyres very light, limited braking, lethal accident waiting to happen at highway speeds.
How about on your own property at walking pace, I'm assuming that none of the pictured pick ups/trailers had permanent deformation from the loads, therefore would that be ok?
Long rambling post I realise, but just wondering what safety factor is built into components?