You can still calibrate your Air Scale sensors if you don't have easy access to a certified scale that gives axle weights. You'll just have to do a little math.
First, pull only your steer tires onto the scale and get that weight. Next, pull forward until your drives are also on the scale and get that weight. Last, pull forward until the trailer tires are on the scale and get the total weight of the truck.
You've got all the weights you need to calculate your axle weights. We will use some generic weights to show how to make the calculations:
Steer weight = 11,000
Steer + Drive weight = 41,000
Total truck weight = 71,000
The steer weight is good as-is and can be entered for calibration.
To get the Drive axle weight, subtract the steer weight from the steer + drive weight:
41,000 - 11,000 = 30,000
To get the trailer axle weight, subtract the steer + drive weight from the total truck weight:
71,000 - 41,000 = 30,000
Now that you have each axle weight, you can begin calibration. For our example calibration, we would enter the weights like this:
Steer = 11,000
Drive = 30,000
Trailer = 30,000
If you've got your axle weights calculated, and you're ready to calibrate, our article How do I calibrate my Air Scale sensors? will walk you through it.