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When it comes to truck stereotypes, there’s one part of the culture that most motorists seem to hate. And that is rolling coal. Maybe you’ve seen it happen on backroads or on the highway, a pickup truck with plumes of black smoke coming from its exhaust. To some, it might look cool, but rolling coal is also illegal. 

What is rolling coal?

Largely exclusive to trucks, rolling coal is the result of modifying a vehicle’s emissions control. By making the air/fuel mixture extremely rich, you get a huge cloud of exhaust smoke. To put it in simple terms, a large amount of fuel goes into the engine’s cylinders, and then you bypass or remove some emissions components. 

With the air/fuel mixture being rich and pushing it past the Stoichiometric ratio, you can roll coal. Typically, the EGR (exhaust gas recirculation) valve control is bypassed by using modification kits. Some folks will even remove the catalytic converter on their truck to roll coal. And with no controls over emissions, that is when you see those big old plumes of smoke. 

Is it illegal to roll coal?

Because of the removal or modification of emissions control, rolling coal in a lot of cases is actually illegal. Although, it doesn’t seem like that deters folks from doing so. According to Car Throttle, under the Clean Air Act, any emission-control tampering is not legal. 

A truck with a smoking exhaust, is it illegal to roll coal?
Truck exhaust | Universal Images via Getty Images

Initially, rolling coal started out in the sport of truck pulls. In that context, a lot of smoke is supposed to demonstrate horsepower and torque. But now, rolling coal is popular among regular road trucks. Sometimes being referred to as “Prius repellent.”

Truck culture can be weird

People love their trucks, and for some folks, making modifications is just a part of the game. Growing up in rural Kansas, I do have to say that I am definitely familiar with rolling coal. This part of truck culture can actually put more stress on vital components of your vehicle, depending on how you achieve getting those black plumes of exhaust smoke. 

With today’s gas prices, it can be expensive as well. When you roll coal, you are essentially wasting fuel. Another consequence is gunking up your oil quicker. And that means you might find yourself having to do oil changes more often. 

A truck wheel with spikes on it.
Spiked lug nut covers | United Pacific via Raney’s Truck Parts

Then there’s the case of other motorists. I’ve seen truck drivers roll coal with no regard for their surroundings. And frankly, that can get pretty annoying if you fall victim to compromised visibility due to the smoke. So in addition to being illegal, it can also show a lack of courtesy. 

At the end of the day, I’m not here to tell you what or what not to do with your truck. This is all just something to keep in mind when it comes to making modifications. And if you were wondering if it’s illegal to roll coal or not.

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