I've driven trucks most of my life, and I've learned a lot a long the way, but when I first started, it was with a gas job triaxle dump, well the loader went to lunch, so I loaded it myself out of the bin full of the stone they use for black top, that real tiny stone, cause they paid by the ton.
I didn't know you could get that much weight on a truck, that old 60's girl was bowed in the center, and it had a double transmission, with a 5 and a 3, but I didn't need to worry about that with that weight.
I took off, and got a run for that little hill, I swear I could hear the pistons fireing one by one by the time I got to the top it seemed, I almost didn't think I was, and this was just a little hump, and it was 500 and sum cubic inch, I can't remember now, but a Ford, well I got to the scales, and the scale man came running out saying get the hell off his scales before I broke them.
Well I had to take it a little ways to the asphalt plant, and I only got to third gear, or fourth on the first box, I never even shifted the other, then it seemed to not have no brakes, thank God there was nothing around, and plenty of room to pull in.
That is when I learned real quick about over loading a truck, it could move, but very slowly, and the brakes, seemed like I was pushing on a balloon for all they done, good thing I was only going 15 to 20 mph.
The brakes would only work at walking speed with that weight, they figured I was well over, I can't remember what it was now, but they weighed tractors and trailers on that same scale, but some how I was way more then what they weigh to, so they can handle extreme weights for short periods, it just isn't safe.
They put the tonnage rating on them for a safe margin, so they have plenty of good braking, plus the HP to pull it at safe speeds without anything breaking.
I was real lucky I didn't blow out a tire in that 1/4 mile trip, plus the loader never let me load myself no more, but I was young, and didn't know no better, you learn from your mistakes.
A real good example of how trucks handle heavier loads is the Michigan centipedes, with all them multi axles under them, they haul over 120,000 pounds all the time, they take off quick, and stop fast, cause they have all them axles, with brakes, and bearing's, to handle the extra weight.
I had a friend that quit from pulling a centipede, and went to pulling a 5 axle like the rest of us, but they offered him an permitted overload, which when enough money is applied, they give you the permits to overload a little, well he went even more, cause he figure he used to pull that kind of weight all the time, and never thought about him only having 5 axles now.
Well he said he was never so glad to get that load off, and glad he never got caught with it, cause it was real hard to stop he said, he said I never thought about only having 5 axles of brake shoes now, and he said that sure does make a big difference at higher speeds, and getting it moving was harder to, not having all them bearings in the axles either, cause he had the same tractor, just a different trailer.
He said he had to give more then double the stopping distance then he normally did, and if an emergency had arisen, he wouldn't of been able to stop.
Those bigger trucks also have wider brake shoes, and when your trying to stop all that weight, you need all you can get, that is the most fearful thing is getting it stopped in time.
Kerry