My press car has a nice new set of tires on it, complete with those little protruding thingamajigs. I had to knew what they are called, so of course like all self-respecting folks alive in 2014, I Googled it. Turns out they have a funny name that I won’t soon forget.
From Bridgestone’s Website:
What are those tiny hair-like things we see on new tires?
In order to make the tire completely fill the mold, the segments, as we said, push in from outside while the bladder pushes out from the inside.
As all this pressure forces the rubber into the mold, air could be trapped, preventing the rubber from completely filling in each mold detail.
To prevent this, molds have tiny holes in them that allow the air to escape. As the rubber fills the mold, some of it is forced into these air holes, and that is what creates those hair-like projections.
Incidentally, the technical term for them is “vent spews.”