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What Is the Purpose of Tire Hairs?

Have you ever wondered about those funny rubber spikes on tires many call tire hairs? You can recognize them as little bits of protruding from random places. They almost look like the stubble that appears when someone hasn’t shaved in a few days.

Why do tires have hairs? Do they have a function, and if so, what happens to your tires once they wear down?

Let’s find out!

What Are Tire Hairs?

Tire hairs are tiny pieces of rubber that stick out vertically from a tire’s surface. They’re relatively short. Most tire hairs are no longer than a quarter-inch and no thicker than a pencil lead.

Officially, people in the manufacturing business call these small, thin pieces of rubber “vent spews.” That’s a clue to how manufacturers make them. They have other names, like tire nubs, nippers, and gate marks.

Why Do Tires Have Hairs?

You may wonder if odd little formations of rubber have a function. Many motorists figure they must serve a definite purpose. Otherwise, the tire hairs wouldn’t be there right?

One popular theory is that they indicate the age or condition of the tire. The idea is that as long as the tire hairs are present, the tires are safe. Further, the prevailing opinion is that you should replace the tire tires once the tiny hairs wear down with use.

If this is what you have been thinking we’re sorry to inform you that none of these reasons is correct. The truth is that tire hairs are a byproduct of the manufacturing process and have no purpose.

Close up of tire
Tiny tire hairs can often be found along automobile tires.

How Do Tire Hairs Form?

When manufacturers make tires, machines inject rubber into molds. They then use pressure to spread the material evenly throughout the mold. The molds have small holes in them to prevent air bubbles from forming where they would get trapped. Their design allows air to escape.

So the tire hairs are nothing more than excess rubber pushing through ventilation holes, only to harden as it cools. This explains why people in the industry call them vent spews because that’s literally what they are. 

Many times it seems like tire hairs are onle on the side walls of tires, but they exist on the tread too. Tire hairs on the tread get worn off very quickly or are even shaved off by the manufacturer. The hairs on the sides of the tires however can last for a very long time and manufacturers rarely remove them.

hancook tire mold with vent spews
This is a tire mold from Hankook. Note the holes for the rubber to vent out in the corners. While these are on the tread and get cut off or worn down immediately, the ones on the sidewall are usually left because there is no need to remove them.

Pro Tip: Say goodbye to the stubble and learn more about What Is Tire Shaving? The Dying Art of Truing Tires.

Are Tire Hairs Useful?

Tire hairs serve a purpose, but only during the manufacturing process. Inspectors see them as a quick visual indicator that the operations are running smoothly and vents are working.

In other words, if they aren’t present, it could be a sign there’s some mechanical breakdown. Perhaps the rubber isn’t heating enough, the air pressure is too low, or the vent holes are clogged.

Once the tires leave the factory, however, the tire vents are obsolete. They have no function in the real world and certainly don’t indicate the condition or safety of your tires.

But they don’t cause any problems, either, so tire hairs are nothing to worry about.

vent spews on tires
Tire hairs reveal that the mechanical process of making tires is working correctly.

Do All New Tires Have Vent Spews

It’s fair to say that almost all new tires have vent spews, but some tires have more than others. It’s extremely rare to spot a new tire with no tire hairs, but how many depends on the brand.

For instance, one company’s tires may leave the factory with more vents on the treads than the sidewalls, or vice versa. These variations occur because of slight differences in manufacturing processes.

Close up of car tire.
Tire hairs are unproblematic and do not need to be removed unless you don’t like the aesthetic.

How Do You Remove Tire Vent Spews?

Because they aren’t causing any problems, you don’t need to remove them. However, we realize that some people find them annoying or unsightly, so you can remove them if you want to.

The easiest and safest way to remove vent spews is to pluck them. You would pluck tire hairs like you would a real hair. Grab them between your thumb and forefinger and give them a quick yank.

Another easy method is to snip them off with nail clippers. You might want to use a knife or scissors but don’t. It’s never a good idea to use sharp objects around a tire because you could accidentally puncture it.

The best approach may be to leave them alone because they wear off over time. The tire vents directly on the treads are the first to wear off, often within a few miles. The ones on the sidewalls may linger, but they sometimes disappear, too over time.

Pro Tip: Protect your tires by knowing When, Where, and How to Air Down Your Tires.

Look Out for Other Vents! 

Now that you know more about why tires have tire hairs, you may start to notice them on other products. They can appear on many objects manufacturers make with a similar process to tire production. These manufacturers will place materials in a mold and compress them. It might look like a hair, or spike of plastic. Many times manufacturers remove them from parts where they interfere with their function or aesthetics.

You might find protruding hairs where you’d never thought to look before, even on rubber or plastic parts for vehicles or appliances. Like the little rubber whiskers on tires, they have no significance and are no cause for alarm. They’re simply unintentional results of the manufacturing process.

Have you heard any strange myths regarding why tires have hairs? If so, let us know in the comments!

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About Tom Morton

Tom, a Pacific Northwest native, is our technical genius. Born in Washington and raised in Alaska before settling in Michigan. He's the man who keeps our operation running, both figuratively and literally.

With a background in Electrical Engineering, Tom specializes in RV solar systems and lithium batteries. He made history as the first documented individual to use a Tesla battery module as an RV battery. Tom has personally assisted countless RVers with system installations and has educated thousands more through his videos and articles.

Cinematography is another of Tom's passions, showcased in his work on the Go North series. You can see his camera skills on display in The RVers TV show on Discovery Channel and PBS where he also stars as a co-host.

Tom's mechanical expertise extends beyond RVs to boats, planes, and all things mechanical. He's renowned for taking on maintenance and repair projects single-handedly and is often spotted underneath RVs, making him the technical backbone of our endeavors.

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Daniel

Tuesday 28th of February 2023

What ignoramus would think that it measures the wear on your tire like do you actually drive on that side of the freaking tire?🙄

Brent

Tuesday 28th of February 2023

“Tire Nipples” That’s all I’ve ever heard them called? But maybe in danger of Internet censorship or abundance of caution, TireNipple was too far over the edge? Definitely like my new tires to keep the nipples as long as possible.

John horstman

Tuesday 28th of February 2023

You may want to learn more about how a tire is built if you think that rubber is injected into a mold ... so much mis information nice try though ..

TG

Tuesday 28th of February 2023

Tire hairs not harmless. When they fall or wear off they are scattered in the environment. Manufactures save their labor by not trimming at factory. With millions of tires on road equals billions of rubber nibs.

Bob Laird

Tuesday 28th of February 2023

Tires are not ejection molded. Need to check your source of this information. A mold for tires is a two piece mold, upper and lower. Vents allow air to escape as a green tire is forced into the mold