The Reason Why Your Car's Tires Are Black

Daniel Kalisz, Getty Images
Daniel Kalisz, Getty Images

With the possible exception of some Big Wheels or other child transportation vehicles, most tires are black. You’d be hard-pressed to find a tire shop and come across a Goodyear or Michelin sample that’s any other color.

Natural rubber, however, is closer to an off-white shade, and early-model cars sported that lighter color. Early tire makers also often added zinc oxide to their natural rubber as a way to strengthen the material, resulting in white tires. But at some point, tire manufacturers decided to go darker. Why?

Jalopnik automotive journalist David Tracy pondered the question when he visited Detroit’s Ford Piquette Avenue Plant Museum and came across the white tires of a Ford Model T, a vehicle that began production in 1908. Tracy posed the question of the color transition to Michelin, which informed him that tires changed color when manufacturers began adding carbon black around 1917.

It wasn’t for cosmetic purposes. Carbon black—an elemental carbon made from the incomplete combustion of gas or oil and collected as particles—increases a tire’s durability, in part by blocking damaging UV rays that can cause rubber to crack, and by improving road grip. It also improves tensile strength, making tires more resistant to road wear.

Older tires that weren't treated with carbon black were good for 5000 miles before they needed to be replaced. Tires made with carbon black, meanwhile, could be driven for 50,000 miles or more.

There was another wrinkle: World War I led to a shortage of zinc oxide, as it was needed to make ammunition. That’s when carbon black became tire companies' go-to strengthening material (though zinc oxide does still play a role in the tire-making process today). Carbon black was initially supplied to tire manufacturer B.F. Goodrich by Binney & Smith, the company that produced Crayola crayons, which originally sourced the material for a line of ink pens.

Was that the end of the tire color evolution? Almost. Early on, companies decided to try and limit production costs by only adding carbon black to the treads, inadvertently creating the whitewall tire with a white sidewall and dark treads. The two-tone look is still popular among classic car collectors today.

[h/t Jalopnik]

Why You Shouldn’t 'Heat Up' Your Car's Engine In Cold Weather

iStock/borchee
iStock/borchee

When the inside of your car is no warmer than the frozen tundra outside, it’s easy to believe you need to let your engine “heat up” for a minute or two by idling in your driveway before driving away. The old adage goes that giving your engine time to reach its normal operating temperature is easier on your car than hitting the gas as soon as you turn the ignition on. One 2009 study showed that, on average, Americans believed a car's engine should be left to idle for nearly four minutes in subfreezing temperatures—but it turns out this behavior is not only bad for your wallet and the environment, but your car as well.

In 2016, Business Insider spoke with former drag racer Stephen Ciatti to get to the bottom of this widespread myth. Ciatti has a PhD in mechanical engineering from the University of Wisconsin-Madison and has worked on combustion engines for nearly 30 years, so he knows a thing or two about how to best treat your car. And he says that idling your machine in the cold only leads to a shorter lifespan for your engine.

In older car models that relied on carburetors to run, frigid weather did pose a threat to engine performance. Gasoline is less likely to evaporate in colder temperatures, which would have led to carburetors failing to get the right mixture of air and fuel into the engine. This sometimes caused cars to stall out, and that's likely what led to the practice of heating up our vehicles in our driveways in the winter. But if you’re driving a car that was made in the past few decades, this is no longer something to stress over. Beginning in the 1980s, car companies began replacing carburetors with electronic fuel injection, which uses sensors to calculate the correct mixture of air and fuel to supply your engine with.

When temperatures dip below freezing, your engine is already aware of this and adjusts by introducing more gasoline into the fuel mix. By letting your car idle, you’re subjecting your engine to more gasoline-rich fuel than necessary, and this ends up stripping oil from your engine’s vital components.

"Gasoline is an outstanding solvent and it can actually wash oil off the [combustion chamber's] walls if you run it in those cold idle conditions for an extended period of time," Ciatti told Business Insider. He said this washing action can gradually "have a detrimental effect on the lubrication and life of things like piston rings and cylinder liners." So in the end, what you intend as gentle behavior toward your car’s engine could turn out to be the opposite.

Once your engine reaches a temperature of around 40 degrees it switches back to its regular fuel mixture, but idling doesn’t help it hit that point any faster. According to Ciatti, the fastest way to heat up an engine is to actually drive. But don’t take that as an excuse to go gunning down the driveway: Your engine will take between five and 15 minutes to reach a normal temperature from the moment you hit the gas. Until then, go easy on the pedal to avoid putting additional stress on your engine.

This article originally appeared in 2016.

The Reason Elections Are Held on Tuesdays

Joaquin Corbalan/iStock via Getty Images
Joaquin Corbalan/iStock via Getty Images

Ever wonder why Americans always vote in federal elections on Tuesdays? There are a few reasons—including a little something to do with the horse and buggy.

Between 1788 and 1845, states decided their own voting dates. In 2012, then-Historian of the Senate Don Ritchie told NPR that strategy resulted in chaos, a "crazy quilt of elections" held all across the country at different times to pick the electors—the white, male property owners who would cast their votes for president on the first Wednesday of December. In 1792, a law was passed mandating that state elections be held within a 34-day period before that day, so most elections took place in November. (Society was mostly agrarian; in November, the harvest was finished but winter hadn’t yet hit, making it the perfect time to vote.)

The glacial pace of presidential elections wasn't a huge issue in the late 18th and early 19th centuries—communication was slow, so results took weeks to announce anyway—but with the advent of the railroad and telegraph, Congress decided it was time to standardize a date. Monday was out, because it would require people to travel to the polls by buggy on the Sunday Sabbath. Wednesday was also not an option, because it was market day, and farmers wouldn’t be able to make it to the polls. So it was decided that Tuesday would be the day that Americans would vote in elections, and in 1845, Congress passed a law that presidential elections would be held on the Tuesday after the first Monday in November.

This article originally ran in 2012.

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