Tandem Setting Formula

This was shared to me on Monday by a guy on my new route. So simple, it's unbelievable!


Tandem Setting Formula

Each tandem hole = 250 lbs.
Maximum Gross Weight (Truck/Trailer/Cargo) = 80,000 lbs.
Maximum Front Steer Axles Weight = 12,000 lbs. (Front Tractor Axles)
Maximum Drive Axles Weight = 34,000 lbs. (Rear Tractor Axles)
Maximum Trailer Axles Weight = 34,000 lbs. (Rear Trailer Tandem Axles)

Example 1
Gross Weight = 80,000 lbs.
Front Steers = 11,200 lbs.
Drive Axles = 36,000 lbs.
Tandems = 32,800 lbs.

Your load is not legal. You are 2,000 lbs. overweight on your Drive Axles.

To figure out where your tandems need to be, use the following formula

Drive Axles 36,000 lbs.
Minus Tandems – 32,800 lbs.
-----------------
3,200 lbs. (Difference)


Divide the difference by 2 (2 axles, Drives and Steers)

3,200 lbs. / 2 = 1,600 lbs. proportioning weight

Now take the proportioning weight and divide by 250 ( this is the # of lbs. per hole)

1,600 lbs. / 250 = 6.4 holes

In this case, your drive axles have too much weight, therefore they are the problem. So to properly proportion your load, you will always SLIDE TOWARDS the problem.

So you will slide your tandems FORWARD 7 holes (since we can’t technically slide 6.4 holes).


Example 2
Gross Weight = 79,400 lbs.
Front Steers = 11,600 lbs.
Drive Axles = 30,600 lbs.
Tandems = 37,200 lbs.

Your load is not legal. You are 3,200 lbs. overweight on your Trailer Tandem Axles.
To figure out where your tandems need to be, use the following formula

Drive Axles 37,200 lbs.
Minus Tandems – 30,600 lbs.
-----------------
6,600 lbs. (Difference)


Divide the difference by 2 (2 axles, Drives and Steers)

6,600 lbs. / 2 = 3,300 lbs. proportioning weight

Now take the proportioning weight and divide by 250 ( this is the # of lbs per hole)

3,300 lbs. / 250 = 13.2 holes

In this case, your trailer tandem axles have too much weight, therefore they are the problem. So to properly proportion your load, you will always SLIDE TOWARDS the problem.

So you will slide your tandems BACKWARDS 14 holes (since we can’t technically slide 13.2 holes).

Use chalk to mark your tandem holes so you know where to slide and how far.


Now, if you don’t have enough holes to slide forward or backwards, your load must be re-worked (unloaded and re-loaded and redistributed) by the shipper because you will not be able to get it DOT legal.

Download here for your smartphone or laptop (Uses Adobe Reader. Free from adobe.com for laptop, or free from app store or google market for smartphones)
View attachment 68866

 

I've put it in a pdf format so y'all can download it to your laptops and smartphones. Just be sure to download Adobe Reader from app store or the google market to view it on your phones (free to download). It can be downloaded from adobe.com for your laptops for free also.

View attachment Tandem Setting Formula.pdf

 

yeah, it's just a base formula based on 12,000 steers, 34,000 drives, 34,000 tandems.