Tandom Question (Where does it go?)

I never pay attention to the six hole thing nor the 250 pounds per hole. I have seen my trailer be anywhere between 350 and 500 pounds per hole depending on how the trailer is loaded. The actual rule for distance is how ever much the legal limit is for that state from the kingpin to the center of the rear tandem axle. Example is CA is 40 feet from the kingpin to the center of the rear tandem axle.

 

Unless they put almost all of it at either end, you will not be over, no matter where you put the axles at 35,000 lbs.

 

Takes some experience to get confident in choosing when to scale, picking up a heavy sealed trailer, would probably require a scale ticket.
If you can see into the trailer, it helps you in your decision, if they load the trailer 1-2-1 and the palets, are at the rear door..you may be heavy on the tail.
If you see everything loaded towards the front of trailer..slide your tandems all the way forward and roll.
This is asuming all palets are the same product and size..liquids etc.
Had a load of oil in quarts and gallons, good thing I read the bol and scaled..back was over weight 2000 pounds..didnt look it, looking at how the trailer was loaded.

 

This is actually the first time in 10 years I have ever heard of this. The correct way to do it is to scale the load. Fill the tanks. Slide the tandems and re scale the load. You scale before you fill if you are in danger of being over gross. If not then fill the tanks first.

Slide the tandems to the rear for a smoother ride unless you are dealing with the different bridge laws. The 250 pound weight is for the small holes but the large holes are around 600 pounds. If you are carrying the same freight you will get to where you can eyeball it.

Remember the weight on the steers is not necessarily limited to 12,000 pounds. My axles are 12,500. The limit is the lower of the limit of your axles (found on the drivers post) and the tires (found on the sidewalls.)

 

I kinda just look at it. If the wheels are too far back or forward for the weight, load distribution, and height I adjust according. I just got out of California, I think the tandem law there puts you mostly forward. (I carry a tape measure just in case the trailer '40 isn't marked out) But nobody is going to do this for you. Don't worry, be happy! It's just part of the learning curve.

Some Russian O/O in Detroit a while ago said he just lines up the tandems with the last pallet in the load. I do that sometimes if it's short and heavy.

Good idea to weigh, though, when the cargo is over 30K.

 

This pretty much sums it up. Let's first assume we're talking about 53' trailers for those new guys who read this later. "Rules" only apply to "common load patterns". Problem is, where people get in trouble is picking up loads with UN common load patterns.

Imagine a trailer that is loaded evenly with product back to about 35 foot, and this product weighs 25,000 pounds, then the last 13 feet is loaded with a heavier product that weighs 20,000 pounds. Any change in the "pivot point" is going to be greatly exaggerated as compared to the opposite arrangement.

Trailer tandem position affects the FULCRUM point, but the real weight shift all depends on how the "load" (weight ahead of tandem center), and "force" (weight behind tandem center) is arranged in the trailer, which can vary anywhere form a little, to wildly. What we are dealing with is how much weight we are REMOVING from the drives based on the amount of weight (Force) that is situated behind the trailer tandem center.


These "simple minded" pointers and "rules of thumb" are getting a lot of people in trouble and it needs to stop. WEIGH YOUR LOAD is the only to know for sure, or use any available weigh gauges to guesstimate. Where did they single any pallet(s)? Do you know? Is all the product pallet weight the same? Is the cargo load weight all even and evenly distributed from front to back? Do you know how many pallets for sure? If you don't know the correct answer to any/all of the above questions then you need to scale the load is the only way to know.

Also consider ...

 

In engineering the course that deals with these issues is call Statics. If you have an interest in flying an aircraft then you are dealing with weight and balances. My point is that we as truckers deal with things everyday that are more complex then we realize. We sometimes underestimate our worth because the only thing we can hold up is our CDL and our logbook. If you combine all the knowledge that we need to do our jobs correctly and safety then I am sure you understand that we are underpaid.

 

Don't measure from the back as suggested. All bridge laws are measured from the kingpin (IIRC).

Mikeeee

 

53 foot trailer, 3 foot kingpin setback...50 feet..measure 10 feet from rear.
Easy math.

 

To me it was always confusing to think of "sliding the tandems". The tandems are stationary, it's the box that you're sliding. The weight is in the box, so by sliding the box you're sliding the weight. If you need more weight back on the tandems, push the box back. If you need more weight up front on the drives, pull the box forward. Just slide the box where you need the weight to go. This was helpful to me when I was new.