Tandem Setting Formula

what happens if you need to move back 8 holes and only have 6
send three messages to dispatch and see you in the morning



common sense isnt very common
without a spreadsheet

 

I was referring to loading heavy loads (42k+) back past the 48 foot mark that "shippers are not supposed to do". This is another situation when your per-hole weight shift number will no longer be valid.

 

Ummmmmm no, well not in my world, 5th wheel 250lbs per hole, trailer tandems 500 lbs per hole. 3300 lbs would be 6 holes, and the 300 is left as you are allowed a 500 lbs differential in your axles as long as you are not over your gross. but then again what do I know 40 years of playing this game and have not ever been cited for overweight.

 

There's reason/s for that.

Space between holes vary by trailer manufacturer, e.g., Great Dane v. Utility, and those can vary by year of manufacture, and weight distribution varies by load.

It's fine and reasonable to find a rough baseline for adjustment, but with the many variables nothing can be written in stone.

 

Blah blah blah.

30000 pound load....drop 2 zeros
300 per hole.

Don't overcomplicate things.

 

That's been my general go-to rule-of-thumb. I was going to suggest to the OP imagine an empty 53 foot trailer, a 53 foot trailer with 22,000 lbs in it, and a 53 foot trailer with 44,000 lbs in it, all equally distributed to the 48 foot mark. Now is the OP going to try and tell me that 250 lbs per hole going to apply to all 3 trailers? Never mind weight distribution and product mixing for the purposes of this explanation. The point is, all heavier loads are not the same, and the amount of weight makes a difference as well as where the weight is in relation to the trailer floor.

When they single twice in the front half of the trailer, that means you have more weight situated near the rear of the trailer, meaning each 6 inches of pivot point change with the trailer tandem position will be more amplified.

 

this is a great tool

 

Geez, are you all serious? Now that I know some of you are so gullible and easy, I'm going to write a simple "slider app" and sell it for $5 a pop and make millions off of all the new guys ... I'll have to put a small disclaimer in fine print buried in the help area that basically says "there really is no complicated formula per say but it will give you a number that will work 7 out of 10 times and you can try it anyway at your own risk"

I'm off to work and will be banging on my computer for a few days ... app store approval, here I come!

 

Assuming a uniformly loaded trailer and a 80,000 gross combination weight, every inch you slide shifts ~55 pounds. 4" hole spacing means ~220 lb/hole. 6" hole spacing means ~330 lb/hole.


Again that assumes:

1) uniformly loaded trailer (this is very often not the case)
2) 80,000 gross. At 65,000lb gross, 1 inch is ~45 lb (again -- uniformly loaded).

 

The trailers I pull when you slide the tandems are around 400-500lbs per hole. If im pulling a heavy load right around 78-80k lbs I will adjust my axles to where my PSI guage for my drives is right around 70-72psi and then I will scale it. Then adjust as needed and hopefully don't have to do a reload.