How to scale a heavy truck

Look at your 5th wheel. Some have about 2" wide slots set about 2" apart and have a single "tooth" that engages it. Others have about 1" wide slots with two "teeth" close together engaging it. (On each side) if you have the wider setup, moving a loaded trailer 1 notch forward on your 5th wheel will move about 500 pounds from your drives to your steers. If the smaller notches, about 250 to 300 pounds will be moved per notch.

When you go to move your 5th wheel, first make sure it's lubed up with WD-40 on all moving parts including the slider. Then crank your landing gear all the way to the ground. Dump your air suspension and wait til it's all the way dumped. This takes the pressure off your 5th wheel. Push the 5th wheel slide button on the dash. Line up something on the truck to something on the ground, put it in gear and very gently let out the clutch, just barely moving the truck the opposite direction you want the weight to go and only the amount you need. Re-engage the 5th wheel pins (just flip the switch) and gently rock the truck to snap the pins in. Refill your air suspension, raise your landing gear and go weigh it to see how you did.

Yeah, I know someone will claim you can burst your air bags doing this. That only happens if you're rough with it.

Trailer tandems will move between 300-400 pounds per hole between the drives and the tandem depending on spacing. You'll have to play with that one to get the hang of it. Weight movement on the trailer tandem is opposite that of the 5th wheel. If you want to move weight forward from the trailer tandem, move the truck forward.

*zips on The Suit and waits*

 

Everyone has left out one critical part of the equation...how does the fuel weight get disbursed?

Depending on capacity of your tanks is one issue on how much total weight fuel will give you. With your tanks at less than half (on the gauge) weigh tractor only, then go put on 100 gallons and reweigh. Compare the two weights, make a note of what percentage of the weight from the fuel goes to the steers and what percentage goes to the drives.

You will need to know this when you are pulling max loads...so you will have the information about weight loss approaching the highway scale and you can maintain legal scale crossings in regard to weight on steers and drives. Also keep track of gallons consumed per mile (mpg) so you can estimate how much fuel you can put on before reaching the scale....

 

Injun, great post!
Otherhalftw, Good points as well.

I guess my point is keep it simple. I do all my calculations assuming the tanks are full!
If ya weigh the combination MT with full tanks, then it's never gonna weigh more than that.
ie; 80k. gross - 32.5k MT = 47.5k. payload in my case. With my 5th. set as-is,,,I know anything under 47.5k. won't be a problem. I actually never haul loads that heavy in a drybox anyway. I guess if I got paid by the hundred weight I might play the "fuel-game" to stay legal as you suggest. I don't know exactly how much a gal. of fuel weighs, but I've always figured it at 8 lbs.

 

8 is a good unit to use...actually diesel weighs 7.468 lbs per gallon and that can vary slightly depending on additives...so 8 is the right way to figure...better high than low.....some dopers use the same philosophy!

 

I get paid by the cwt... if I go BACK to the shipper it's for more product.

As far as portables go... how often do you see them? Not very... I seldom cross any scales anymore as they are not worth the hassle.... I simply go another route.

 

Don't forget that in the winter time ice and snow can add a lot of weight to the equation. Also when hauling fresh veggies and stuff straight from just being picked the ice them down and as you drive along you lose a bunch of weight.

 

well we all can say do this and that but there are to many variables. I'm not very familiar with freight shakers but if your tanks r in the back(under the bunk) and u have an APU(400-500lbs) then almost 3/4 of ur fuel weight is on the drives as well as APU weight so it may not be possible to get all the legal weight on your steers. You aslo have to keep in mind all these broke states and some are writing tickets on overhang laws so you can't just slide the tandems all the way forward. My advice to you is figure out a hole on your fifth wheel where you can get the most weight on your steers and still axle out your drives then never move it.Also pay attention to how they load your trailor.Figure out where you want the weight to go and make sure they load it that way(little extra time on the dock is better than having to come back and waiting to have it reloaded). Also if you own the truck, if you keep the drives and tandems balanced out evenly your truck will pull better and use less fuel$$$. Sorry so long.

 

Overhang laws? anybody else wondering what this is? I am...over length on the tandems (CA 40' bridge law) is one thing....somebody help me out here!

 

There are some laws that you cannot overhang more than a certain amount ahead of the trailer PIN (center of 5th wheel). For instanst, Alberta says 10 feet maximum.

Doesn't matter where the 5th wheel is sitting except if it changes your bridge or overall lenght to the point of making you illegal.

 

I am also unsure of what overhang laws are. I also have never seen a rig where you would have close to 10' in front of the pin. I believe our vans have 36" pins, flats 24", and steps 18". You would need a seriously stretched out rig to have a 10' deep pin.