You're pulling 200 bushels of soybean seed in a seed tender with a three-quarter ton pickup. Or maybe you're pulling two wagon loads of baled hay hooked together with a one-ton truck. Fred Whitford says the question isn't can you do it, at least for a while, should you do it? And is it legal to do it?
Whitford, director of Purdue University Pesticide Safety programs, has just issues his newest booklet, PPP106, "The Truck-Trailer Combination Vehicle" which is more about determining if your truck is big enough for the job you're doing than if the truck could do the job.
You may not be into math, but part of it is discovering what numbers you need to know, where to find them, and what they mean to towing capacity, he says. The goal is more preventing accidents than avoiding tickets, although a better understanding of towing in general could allow you to do both.
Here's a basic example. Suppose you want to haul home a tractor and loader you just bought at an auction with your truck and gooseneck trailer. First, find the rating plate for the trailer. In this case it says you can carry 14,000 pounds. Next the rating for the trailer hitch ball should be on the top of the ball. In this case, it's 6,000 pounds.
When you hook the truck to the trailer you create a supervehicle, Whitford says. So in this case, you're towing capacity isn't 14,000 pounds that the trailer can carry, the maximum is the 6,000 pounds that the trailer hitch ball is rated for.
It may look ok and you may get by with it, for a while. "Just passing the eye test isn't good enough anymore," Whitford says. "You need to understand the numbers and make sure what you're doing is correct."
You can obtain the new publication or instructions on ordering from Purdue Extension.