Some time back I was up in Oklahoma and got involved in a “Rig Move”. Oil Rig that is…big hole puncher.. capable of putting a hole miles deep in the ground. There’s a place in Oklahoma City that makes oil rigs. Naturally after they’re sold they have to be transported.

Ta Da!!! That’s what I do. I Transport big stuff.

So I’m at the “shipper” about daylight….and loaded and rolling about nine thirty in the morning. Perfect. Curfew wasn’t over until nine anyway so I couldn’t be rolling much earlier. I planned on being in Houston the next day. It was shipping out on a boat from some port down there.

So I’m toodling along with an SCR House on my trailer. I have no clue as to what that is or does other than it’s part of an Oil Rig. It’s also about forty foot long, maybe eleven foot wide, twelve foot tall and weighs sixty five thousand pounds. Pay’s pretty good too. All in all it’s just about as close as you can get to a “perfect load”


At any rate somewhere south of Ardmore Ok. on I35 there’s a chicken coop. Just my luck it’s open. So I roll in. No big deal since I generally stop at EVERY open scale and stop and talk to the nice gentleman (or lady) running it. It’s part of the job….just time consuming and that’s something OverSize has very little of in winter…..Time. They normally want to see my permit, registration etc. I show it all to them and it’s “have a nice day” and I leave….quickly.

This time it was a little different. There were two other Oversize in there ahead of me. They looked to have been there a while.

Ooopsie.

Two over axle oversized loads. One was over on his trailer by about seven thousand pounds. This cost him about six hundred dollars. The other….coincidently enough…was on the same Rig Move that I was, leased to the same company that I was. He’d apparently loaded the day before and was just now here. He was over about three thousand on his trailer.

The pitiful part of it was that he was clueless. He didn’t know axle weights from bacon grease. It seems that we were running short on trucks for this rig move and his dispatcher talked him into “helping out”. (He was normally in short-haul general freight.) . Do her a “favor” she said. He didn’t want to but dispatchers determine driver income and you mostly do what they say……or starve.

So he did.

He knew nothing about the trailer he hooked onto to go get the piece. It was a 3 +1 stretch lo-profile stepdeck….all his experience was with two axle non stretch normal profile spread axle stepdecks.

He knew nothing about shimming.

He knew nothing about the “pin” between the three and the one. (3+1) or when to use it or not.

He knew nothing about maximum (unpermitted) lengths.

He knew nothing about axle weights.

He loaded an eighty three thousand pound set of DrawWorks.

He was very, very lucky.

He managed to deliver the load late the next day with “only” a four hundred dollar overweight ticket AND about a seven hundred dollar charge (dunno who pays it) for blowing out two tires and service call for changing those tires on the side of the road.

It could have been a whole lot worse. Much, much worse. I could go on and on about the problems involved…all the things he DIDN”T know… ..but for now let’s just focus on what got him the ticket…and blew out his tires.

Axle Weight….and excess thereof.

Weight. It’s broken down into two types. Gross weight and axle weight.

Legal trucks of the five axle variety have a set weight nation wide. It can vary some state to state but only IN state. Nationwide the Legal max is 80,000 lbs gross of which the max axle weights are 34,000 lbs on each set of tandems, that is, the tractor drives and the trailer. Sometimes the steer axle is specified as 12,000 and sometimes not.

Heavy haul is a bit different. After we pay the nice man we’re allowed more weight. The amount varies from state to state. In Oklahoma and Texas it’s (roughly) 20,000 an axle. Since he had a seven axle rig he would have been allowed 140,000 gross. He would have had to have been over 57,000 empty weight to NOT be able to handle 83,000 pound draw works. And he wasn’t. His gross weight was fine.

The problem (one problem) is that he loaded it too far to the rear of that trailer. This put too much weight on the trailer, about three thousand pounds worth…. and not enough on the tractor.

He asked me if sliding his fifth wheel would help.

How do you react to something like that?

He was serious. He honestly genuinely had no clue as to how to balance a load. He was about forty or so and had been driving for quiet some time. He was an Owner Operator. And he had no idea.

THAT kiddies….is what we’re going to look at. How to axle out.

For the mathematically inclined these are the equations:

A = L - (D x L)/ B and D =B (L-A) /L

where A : is additional load added to the axle

L : is net weight of load

D : is distance to the Center of Gravity of the load from one of the Bridge Points.

B : is the Bridge of the trailer.

Since this is the United States all measurements are in feet and fractions thereof (for example….6 ft. 6in. = 6.5 ft.)
and all weights are in pounds.

A bridge point is the center point in an axle group. The bridge of the trailer is the distance between it’s two (or more) bridge points.

Clear as mud right?

Maybe next time you think truckers are stupid you might reconsider? We have to deal with this stuff every day. Especially heavy haul.