Can someone plz explain to me about sliding tandems

I'm not trying to be mean but this should be a part of basic truck driver training. If you don't understand this, you should go back to your school and find out why you weren't trained in this area.

Having said that, it's simply a matter of physics.
The further your tandems are under your trailer, the more weight they will have to support. if you notice the holes above your tandems and underneath the box, those are for sliding your tandems. There's not really any way of stating for certain how much weight you will move with each hole because it really depends on what is loaded where in the trailer.

Some people say anywhere from 250 to 350 but that is not really an accurate statement either.
If you place a 50000 pound coil in the very front of the trailer and then tried to slide your axles you're not going to move very much weight per hole because there's nothing in the back of your trailer. And vice versa if the coil is placed over your trailer tandems.

But let's say that each pallet weighs the same from the front of the trailer to the back of the trailer.

Your scale ticket says that you are 11000 on the steers, 31,000 drives and 35,000 on the trailer. You know that you need to move at least 1,000 pounds off the trailer in order to be legal.
Personally, when I was pulling a box trailer I liked my drives and my tandems to be as close to even as possible because that is ideal for driving in Winter conditions.

If you add 31000 + 35000 you come up with 66000. 66000 ÷ 2 is 33000.
So by my standards 33000 on each tandem is ideal. So in this case you need to move 2000 pounds. If we go with 300 lb per hole and take 2,000 divided by 300, this will be rounded off to six or seven holes.

Since you are heavier on your trailer tandem then you are on your drives you want to shift some of the weight onto your drives By sliding your trailer wheels back and in this case 6 or 7 holes.

After you scale again you can look at the new weights and determine how much weight you actually moved by sliding six or seven holes and then it's a matter of just doing the math.
You can do this by subtracting the new tandem weight from the old tandem weight. Divide that number by the number of holes that you slid and this will tell you how much weight you actually moved per hole.

In today's tech age we have lots of computer programs and apps on our phones that will help us do this and make things much easier.

Legal Load.
Trucker Math
Trucker axle weight calculator
To name a few.

I would recommend that you clearly understand how this works before you start to use the shortcut apps so you at least have some head knowledge.

And sliding your fifth wheel will usually move more weight per notch depending on the tractor.
Sliding your fifth wheel to the rear of the tractor will take weight off of the steers and place more on the drives.

Oh and one more thing; Some states, like California and Oregon have what is called a bridge law.
The bridge law refers to the distance between your Kingpin and the the center of the front or rear trailer axle. (Varies between states)
This places limitations on how far you can slide your axles. If you can't get legal within the legal limitations you will have to go back to the shipper and get Reloaded.
It is important that you understand this before leaving the immediate shipper area and traveling across state lines.

And unless you have air powered pins on your trailer you're going to have trouble sliding them sooner or later. This is the only tool you will ever need when it comes to releasing your trailer tandem pins.

It's called the Persuader and can be found on Amazon and several other places online.



CA Progressive Engineering 27" 5th Wheel Semi Truck Pin Puller "The Persuader" - OneStop-TruckShop

 

Children are taught to bounce quarters for the proof that the bed is made properly to spec the night before. If there was any time it needed to pas inspection it was made to pass top to bottom regardless of actual denture; recprds

Now that children have in some cases grown into United States Marine Corps they are to duplicate the quarter problem this time with solid brass bed frames in it's entirely. =) They will find a bit of joy in teamwork with a like minded second.

 

Did the O/P ever figure it out?!?

 

If I had been a class instructor and go to the iron skillet for two hours, I fully expect you, the student to blow the whistle on such activity,.

If the school refuses to fire me on your video evidence, time and date stamps etc. then you I think have the right to feel that you are not being traught or trained to your best and should withhold your tuition and whatever else

Some will get LAZY and call it NOW the new NORM.

I. REFUSE. TO.

If a school's training and motivation of staff is so #### and not acceptable by even the greenest of students The school has by the same token lost all expecting and valid demands for paymetn of tuition until corrective action is taken.

Enough is enough. Literally enough. Bring in the State employment board. You will find present up to date records maintained by some students but not all.

New Norm Dies now. Enough is enough as of right now.

If you students in your hudnreds of thousands want to loll around your garden chairs sipping mint Juilepts and pretend to be students playing at trucking... you are engaged in a completion of a circle fraud big enough to destroy these united states as a valid trucking industry.

Enough. IF I had a number of you try to climb into my truck to do a road test on say 4 of you and discovered just how abysmal your training has been up to this point you seriously will collectively have been sent home to retain in a different school., Im not sending you back to the same cesspool to double money on you with more of the same old Norm.

 

I thought I'd bump and piggyback on this thread to point out an interesting thing I ran into today.

I have a 3 drop load of sour cream. It was heavy at 79,500 full of fuel at the shipper with 1/2 tank fuel. Load came to about 5 foot from the trailer doors. Trailer tandem was slid as far forward as would allow, and drives were at 33,700, so this load had some heavier product in the nose for the final drop. Also, there are no single rows. All pallets loaded 2 wide, straight in, all the way back.

Anyway, I get the first drop off (6 pallets and 9,300 pounds) and still at half tank fuel but I notice my drives are now indicating they are in excess of 34,000 lbs, (while my trailer tandems are in the same identical, far-forward position)

This points out the "teeter-totter effect". That little bit of product that was behind the trailer tandem center point was just enough to lighten my drives to a legal point. Removing that 9,300 lbs from the rear, ACTUALLY RAISED the weight on the drives.

I was rolled across the Woodburn, OR scales (north of Winco Foods) and noticed the scale indicated 34,400 but he let me roll.

So keep this in mind in the future. It is possible in some unique situations to lighten the gross by removing product from the rear, but increase the drives weight. This also bears out what I always try and stress, with mixed product loads, you can never take anything for granted or make any "assumptions" about weight distribution or how much weight will transfer by moving "one notch".

 

Reminds me of a story. In my earliest days of truck driving I pulled a box truck. I picked up a load of breaker bars I believe it was in Youngstown Ohio. I hopped up to take a look inside and I saw pallets with breaker bars banded together. I made the mistake of believing that they were banded to the pallet but they were not and I found this out the hard way. Back in those days I drove like an idiot following too close which resulted in me having to hit the brakes all the time. By the time I got to the scales in Illinois going into Iowa I was way way over on my drives. I slid the tandems up and crossed the scale and I was still over and then I went and slid them all the way up and when I crossed the scale I was still way over. They told me that I had to get it right before they could let me go. So I had no choice but to walk to the front of the trailer and cut the bands and start carrying breaker bars all the way to the back of the trailer I think I had to move about two pallets of them in order to get my weight right. Needless to say I started to take a closer look at my freight and I stopped following so close so I wouldn't have to hit the brakes all the time.

My grandfather told me many years ago, truck driving is a thinking job. When you quit thinking, that's when you're going to get yourself into trouble.

 

43,000 on the tandems? I say 50:50 odds you are at JBS Swift Meats in Marshalltown IA. Their dockworkers are all on the crack pipe

 

Weren't you taught this at basic training? Why not ask your boss to show you? and it is so simple specially if its one of the newer trailers you just pop the air valve button and the pins pop out slide it back or forward and push in the air lock which should lock the pins in place and away you go.

 

Slide the tandems in the direction your heavy. i.e. heavy on the drives, slide forward, heavy on the trailer, slide back towards the back of trailer.

 

I am only four weeks into CDL training and already learned how to slide them, calculate ~250 lbs per hole, etc. it’s not really complicated