A tractor-trailer fully loaded can weigh up to 80,000 pounds. That’s 40 tons. In fact, that is the legal weight limit in the U.S. The weight includes the truck and trailer as well as all the cargo carried by the unit. When you weigh that much, it takes a long time to slow down and come to a complete halt.
For this reason, manufacturers give Big Rigs multiple gears to shift through to make slowing easier and faster for the trucker. The average truck has a total of 10 gears. However, some manufacturers load their trucks with more. There have been as many as 18 gears in a trucker’s crankshaft. These gears give the truck extra power to get up to speed faster. More gears means more energy for pulling all that weight. They also are helpful in slowing down, because if you’re coming around the mountain in a state like Tennessee where there are steep downward slopes and you are pulling 40 tons of dead weight, you need those gears.
Those Gears are For Downshifting
You learn how to do this right in truck driving school. One of the things that we’ll teach you is how to downshift from that top gear to the lower gears easily and efficiently so you can slow your truck down and stop it when you need to. There are times when you an unexpected halt in the traffic can cause you to slow your truck down rapidly and stop in the midst of heavy traffic. It could be an accident or a police checkpoint. Either way, you need to stop.
A good truck driver can bring his truck to a dead stop quickly using all his truck’s gears–whether 10 or 18–and do it without causing panic or hurting anyone. We’d like you to be that truck driver.