Hello There,
I actually happen to be a mechanical engineer and I have been doing some quick back of the envelope calculations here.
Assumptions I made:
65mph ~150kmph at a maximum.
Total weight is ~26000lbs (12k trailer, 8k truck, 6k load on truck) ~13000kg
Total decelleration due to braking occurs in 1 second, which is a worse case scenario.
I figure that under these conditions the truck would be experiencing a force of 546,000N.
Now I'm guessing that the diameter of the bolts that connect the rotors to the hubs are 1/2 inch in diameter and that they are made of structural steel.
I determine that each bolt can handle ~30,000N.
Giving that you have 12 bolts that means that we have a total yield stregnth of 360,000N.
This is less than what I figure the truck is experiencing under the conditions above. So just by this it would seem that they will not hold up.
However, this is assuming that the rear brakes are not working and that you have no trailer brakes. Also, I don't see any truck decellerating this fast.
So there you go. Now its time to put your engineering cap on and make a decision. How much of the force will be absorbed by the rear drums and the trailer brakes? How fast will you be asking your truck to slow down?
Now just for fun if you had 24 bolts total you would have 720,000N capacity and an estimated 560,000N maximum load. Now, even under the worst case scenario, you actually have about a20-30% foctor of safety, i.e. you system is overbuilt by that much. Now go back and look at decelleration and additional braking and your actual FOS is probably 100%, which means that in the end there is a reason those rotors have 12 bolts.
Good Luck,
54 Monster
