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A few days ago, I stopped for coffee at a truck stop. As I was leaving, another customer asked if I was a driver.
He had a scale ticket in his hand, and wanted to know how to get some weight off his drive tires (34,560 lb IIRC, with the legal limit being 34,000). I explained the workings of 2-point support, and how moving one support point closer to the center of gravity puts more weight on it (and takes weight off the other). The practical application of this was that he needed to slide his trailer axles forward - but not bring his wheelbase (kingpin to center of trailer axle group) below 37 feet (in Ontario, wheelbase on a 53 foot trailer has to be between 37 and 41 feet). He didn't know that there was a minimum.
To top it off, he was 300 pounds under the legal maximum on his steer axle, and the combined weight on his drive and trailer axles was 67,900 lb, or 100 lb less than the legal maximum for 2 tandem pairs - and he hadn't fueled yet. In other words, he only had enough "wiggle room" to get 50 gallons/200 litres of fuel. Of course, since this was in Ontario (slightly higher weights allowed than in the U.S.), he could have got (assuming 6 MPG) either 60 or 70 gallons, depending on what crossing point he would be using (different distances, and he'd burn off the "extra" 10 or 20 gallons before reaching the border).
What he didn't know is basic stuff about driving a truck. The school he went to for his CDL should have taught him that - and the company he drives for should have made sure his OTR trainer covered the matter in case the school hadn't, before sending him out on his own.
He had a scale ticket in his hand, and wanted to know how to get some weight off his drive tires (34,560 lb IIRC, with the legal limit being 34,000). I explained the workings of 2-point support, and how moving one support point closer to the center of gravity puts more weight on it (and takes weight off the other). The practical application of this was that he needed to slide his trailer axles forward - but not bring his wheelbase (kingpin to center of trailer axle group) below 37 feet (in Ontario, wheelbase on a 53 foot trailer has to be between 37 and 41 feet). He didn't know that there was a minimum.
To top it off, he was 300 pounds under the legal maximum on his steer axle, and the combined weight on his drive and trailer axles was 67,900 lb, or 100 lb less than the legal maximum for 2 tandem pairs - and he hadn't fueled yet. In other words, he only had enough "wiggle room" to get 50 gallons/200 litres of fuel. Of course, since this was in Ontario (slightly higher weights allowed than in the U.S.), he could have got (assuming 6 MPG) either 60 or 70 gallons, depending on what crossing point he would be using (different distances, and he'd burn off the "extra" 10 or 20 gallons before reaching the border).
What he didn't know is basic stuff about driving a truck. The school he went to for his CDL should have taught him that - and the company he drives for should have made sure his OTR trainer covered the matter in case the school hadn't, before sending him out on his own.
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