There’s nothing like a fresh set of tires. Along with the obvious safety and performance aspects of a new set of hoops, fresh rubber looks and smells fantastic. New tires can really spruce up your car or truck’s looks, and honestly, it just feels good to do something nice for your ride.
Since we’re talking about new tires, have you ever wondered what those wispy little rubber nubs all over new rubber are? What do they do? Why are they there? Are they, like, cat whiskers for tires? Nah, they’re just an odd little leftover from the tire factory.
Those little hairs or nubbins are called vent spews, and they’re part of the final tire production process. See, once a new tire goes through all the initial steps of construction it becomes what they call in the industry a “green tire” — an uncured, raw rubber tire without tread or markings. The final step in the tire making process is vulcanization, which converts the rubber from a soft, sticky dough to the stiff, hard-wearing rubber you see at the local tire shop.
Steam, rubber, pressure, heat
During the vulcanization process, a green tire is put into a massive mold that cures the rubber and applies the tread and sidewall markings. Inside the mold are superheated, steam-pressurized bladders that press the tire against the mold. To ensure full contact between the rubber and the mold and eliminate any air bubbles, the mold is pierced with countless tiny vent holes. As the steam-filled bladders push the tire into the mold, air escapes through those vent holes. A side effect of this is that rubber is also pressed into and through those vent holes.
When the tire is finally released from the mold, it’s covered in hundreds of tiny rubber hairs or whiskers where the soft rubber was pressed through the vent holes. Those are the vent spews. Once the tires are mounted, a few miles of driving will clear them from the tire’s contact patch, but they’ll still be all over the sidewalls. Don’t worry about it. Vent spews are harmless, they don’t affect a tire’s performance or traction or wear or anything like that. If you think they’re unsightly, you can clip or shave them off.
Oh, one quick note — vent spews on a sidewall aren’t necessarily the sign of a new tire. I’ve had plenty of motorcycles come through my garage with 20- or 30-year-old tires that still had a bunch of ’em. The only thing intact vent spews on a sidewall tells you is that the tire has pretty low mileage on it. Always check your tire date codes (and the condition of your sidewalls) if you want to know how old a tire is.
