# A pickle in finding vehicle center of gravity.

1. Apr 5, 2013

### constlurker

So i'm trying to find vehicle center of gravity, but i only have this information:
full loaded vehicle weight(3200kg or 31392 N)
empty vehicle weight(2000kg or 19620 N)
maximum rear axle capacity(1500kg or 14715 N)
maximum front axle capacity(1800kg or 17658 N)

Is this possible? I have a book in which is written(and there is an even an example) where they calculate center of gravity for empty vehicle with just full loaded vehicle weight, empty vehicle weight and maximum rear axle capacity, but i'm reading it and it just doesn't makes sense,i tried calculating the same without actually understanding and the formula is easy but the answer i'm getting is nonsense..So i want to ask experts - can i find center of gravity with just these variables(because there is no other info on the vehicle)? Maybe not 100% accurate, but is it possible?

2. Apr 5, 2013

### Filip Larsen

It is the relative load on the two axles that determines the relative position of the center of mass (CM). So, if you only know the total load, but not the relative load, you cannot calculate the CM position.

In your case it means that you can calculate the (relative) position of the CM from the two axle loads, whereas you cannot do so from the empty weight alone. At least not without some further assumptions, like for example that the relative axle load for the vehicle is the same whether empty or fully loaded, or that the the payload has its CM located at some specified relative position between the two axles.

(Btw, since the maximum weight doesn't add up in kg, but does so in N, I assume you mean 3300 kg for the fully loaded total weight.)

3. Apr 7, 2013

### constlurker

Thanks for the info, i am thinking the same way, but they somehow calculating it for the empty vehicle by distributing weight difference(fully loaded minus empty) into drivers seating, passengers and the rest to the back on the vehicle..So i really have no idea what is even happening there and why are they calculating like that. By the way, it is not a simple book, but a book written by a professors, so i'm kinda lost here.