What Are the Little Nubs on Tires Called?

The little rubber “hairs” or nubs on tires are called vent spews—also known as vent whiskers or nibs. They form during manufacturing when small amounts of rubber are pushed through tiny vent holes in the mold to let trapped air escape. They have no performance role once the tire is made and will wear off naturally with use.

How Vent Spews Form

Vent spews are a normal byproduct of tire manufacturing. When a green (unvulcanized) tire is pressed and cured inside a heated mold, tiny vent holes allow air and gases to escape so the rubber can fill every groove and detail of the tread pattern uniformly. A small bit of rubber extrudes into these vents during curing, then solidifies and remains as thread-like nubs on the finished tire.

Inside the Tire Mold

Modern tire molds have many strategically placed micro-vents to prevent air pockets that could cause defects or incomplete tread definition. After curing, the molded tire is removed and the extruded rubber “whiskers” are left behind. On some tires you may see more vent spews along the sidewall or shoulder than on the main tread, depending on vent placement and mold design.

What They’re Called

While drivers often call them “nubs” or “hairs,” the tire industry uses more specific terminology. The following list clarifies common names and how they’re used.

• Vent spews: The most widely used technical term in tire manufacturing.
• Vent whiskers or tire hairs: Common colloquial terms among drivers and retailers.
• Nibs: A casual nickname, often used interchangeably with “nubs.”
• Sprues/sprue nubs: A general molding term sometimes applied informally, though in tire making these features come from vents, not sprues.

Regardless of the name, all refer to the same harmless rubber filaments formed by vent holes during molding.

Do Vent Spews Indicate Anything About Safety or Quality?

People often wonder whether these nubs signal a tire’s newness or affect performance. Here’s how to interpret what you see.

• They do not affect traction, handling, speed rating, heat dissipation, or ride quality.
• Their presence does not guarantee a tire is “brand new,” only that those specific surfaces haven’t experienced abrasion yet.
• They typically wear off quickly on the tread that contacts the road, but can remain longer on sidewalls and shoulders.
• Quantity and length vary by mold design and brand; more spews don’t mean better (or worse) quality.

In short, vent spews are cosmetic artifacts with no functional purpose once the tire leaves the factory and should not influence purchasing or safety decisions.

Care, Removal, and Best Practices

There’s usually no need to remove vent spews, but some owners prefer a cleaner look. If you’re considering it, use the following guidance.

1. Ignore them: The safest and simplest approach—they will wear down naturally.
2. Avoid shaving the tread: Cutting on the tread can damage sipes or introduce superficial cuts.
3. If removing for aesthetics, use blunt trimming only on sidewall whiskers and avoid cutting into the rubber surface.
4. Focus on real tire health: Check pressures monthly, inspect for cuts, bulges, cracking, or uneven wear—issues that matter for safety.
5. Consult a tire professional if you see anything unusual beyond harmless whiskers.

Leaving vent spews alone is generally best; any trimming should be conservative and limited to non-tread areas to prevent accidental damage.

Summary

Those little nubs on tires are called vent spews, also known as vent whiskers or nibs. They’re harmless remnants from mold vent holes used during curing, carry no performance or safety significance, and will disappear with normal driving—especially on the tread. Their appearance varies by tire and should not influence your assessment of quality or condition.

Is it okay to put regular air in nitrogen-filled tires?

Yes, it’s okay to add regular air to nitrogen-filled tires; doing so is safe and will not cause harm, though it will dilute the nitrogen and reduce its effectiveness over time. The biggest disadvantage is the potential inconvenience of not being able to find a nitrogen-filling station when you need to add air. While pure nitrogen offers benefits like reduced moisture and slower pressure loss, mixing it with air is permissible for topping off your tires in a pinch. 
Why it’s safe:

• Nitrogen isn’t explosive: and is chemically similar to the other “ideal gasses” in the air, making them compatible. 
• No harm to the tire: There are no negative effects on the tire itself when air is added. 

Why you might choose to use air:

• Availability: Nitrogen is not readily available at most gas stations, making regular air a more practical option for quick top-offs. 
• Mixed gases are common: Most nitrogen fills in tires are not 100% pure, so mixing gases is a common practice. 

When to consider refilling with pure nitrogen: 

• To preserve benefits: If you want to maintain the benefits of nitrogen (like consistent pressure and reduced moisture), you’ll need to eventually drain the air and refill with pure nitrogen.
• At a specialized center: This is best done at a specialized service center.

What are the little nubs on tires for?

The small rubber “spikes” or “hairs” on new tires are vent spews, a harmless byproduct of the tire manufacturing process, not a functional part of the tire’s design. They form when rubber is forced into tiny vent holes in the tire mold to allow air to escape and ensure a complete, bubble-free fill. These spews have no purpose and will wear off naturally as you drive.
 
What they are:

• Vent Spews: These fine rubber strands are technically called vent spews, but also go by names like tire nibs or gate marks. 
• Manufacturing Byproducts: They are created when excess rubber is pushed out of the tiny air vent holes in the tire mold during the manufacturing process. 

What they are for (or rather, not for):

• No Functional Purpose: They do not improve tire performance, safety, or any other function of the tire. 
• Indicator of a New Tire: Their presence is a sign that the tire is new and has not been used. 
• No Need to Remove: While they can be trimmed off with wire cutters, there is no functional need to do so, as they will naturally wear away with driving. 

What is the purpose of vent spews?

A spew hole, or vent sprue is the tube that excess pressure escapes from as the rubber expands. Toyo Tires technical manager Steve Burke explains why your fresh tyres have these hairs/nibs/nubs/spews. “Air escapes, ensuring no air bubbles between tyre and mould, and takes with it little bits of the rubber.

What are the bumps on tires called?

The small rubber spikes on new tires are called vent spews, also known as tire nibs, sprue nubs, gate marks, or nippers. They are a natural byproduct of the manufacturing process, where small bits of rubber escape through vent holes in the tire mold to release trapped air. These spikes have no functional purpose and will wear off with normal driving.
 
How they are formed:

1. Molding: A “green tire” (uncured tire) is placed in a mold. 
2. Pressure: Heat and air are applied to cure the rubber. 
3. Air Escape: Small vent holes in the mold allow trapped air to escape. 
4. Rubber Squirts Out: As the rubber fills the mold, tiny bits of it are pushed out through these vent holes, creating the spikes. 
5. Curing: These rubber bits then firm up and remain attached to the tire when it is removed from the mold. 

Key characteristics:

• No Purpose: Vent spews have no impact on tire performance, safety, or balance. 
• New Tire Indicator: Their presence is an indication that a tire is new and has not yet been driven on for long. 
• Wear Off Naturally: The spikes are made of the same rubber as the tire and will naturally disintegrate and wear away with driving. 
• Optional Removal: While they can be removed by hand or with a file, there is no practical need to do so.