lineinthewater

I'm referring to those small (sometimes > 0.5") extensions that line the sidewalls of both sides of the tire. Are those just remnants of the manufacturing process? The normal tires I buy always have long tabs, and my frame is so close to the tire (near bottom bracket) that it will hit and wear down the clearcoat/paint if I fail to cut them when I buy them.

hueyhoolihan

yes, i think they are remnants of the manufacturing process. it's an artifact of the path taken by air escaping when material is injected into the mold. i think it's called flashing.

Retro Grouch 

Two possibilities:

1. When you mold something you have to leave a way for air to escape the mold. Those little fingers of rubber are the result of rubber pushing the air out of the mold vents.

2. They could be "vortex generators". When air hits such an obstruction, it eddys around and can exert a tiny but measurable push against the back of the tire. The amount of force exerted is a function of the surface speed of the tire and the speed of sound so, if you're riding relatively slowly, you'll want longer vortex generators on your tires. When you see TDF riders get a tire change at the start of a climb, they're not be fixing a flat, they're getting tires that have longer vortex generators.

Take your pick.

Homebrew01

Everyone knows it's #2 .... Duh !

lineinthewater

Ah makes sense, I knew I slowed down when I cut them ...

ksisler

L; Car tires also had them in my dad's era. I remember well that he always called them tire-nipples (with a silly solicitious grin). In the modern politically correct era, I don't call them anything. Since I would refuse to buy or ride any bike with tires that close to the chainstays or fork, so I have never had the paint wear issue. I just snip them off new tires with a pair of blunt nippers 'because I want to'.
/K

lineinthewater

Look at the weight savings!

Whiteknight

Tire molds have numerous tiny holes drilled in the molds to allow air to escape when the mold is closed and the "press bladder" is inflated to force the "green" tire into the mold.l A tire going into the press looks like a barrel without ends. Without the holes in the mold the tire could not fill the mold uniformly during the curing process. Auto and truck tires are run through a machine that we called the chicken plucker to cut off the tiny projections of rubber left on the cured tire.

With new bicycle tires I use a razor blade or nail clippers to clean them off the tires. If the tires have the tiny projections on when you ride through a puddle of water the tiny projections throw water in a spray. Some tires may have a thin fin of rubber standing up from the center of the tread area. This shows that the tire was most likely made in a two part "clam shell mold" that did not seal properly when the mold was closed. Some bicycle tires are cured in a multiple piece mold. You will see lines on the sidewalls from the bead to the tread portion.

When Firestoine Tire and Rubber first produced radial tires the management did not want to convert their plants to the multiple piece molds. Insisting they could produce a radial ply tire using the old 2 piece clam shell molds used to produce bias ply tires. They ended up having to recall most of their first radial tire production. Ply distortion during the tire curing process resulted in early tire failure in use. I have seen this ply distortion in some cheap Kenda tires about 5 years ago. After only 100 miles I could see warped ply showing in the tread. My job in the tire plant was watching over the production of the gum dip latex used to coat tire cord before the cord was coated with the tire rubber.

fietsbob

Many single celled organisms use flagella, like that, for mobility in the fluid they live in,
ours is just a thinner fluid.

leob1

They are tire wear indicators. As long as they are there, the tire is still good. There is no need to look at any other part of the tire to tell if it still has any life left.

Nick Bain

They serve as a warning indicator for when you do a tire sweep, if you start to feel them that means your getting your fingers to close to the spokes.

Clawed

Chicken strips! They are a measure of how aggressive you are cornering.

musicgalaxyman

part of the molding manufacturing process, cut them off.

xlDooM

I believe that is called "spew" by pirelli.

squatchy

I thought those were curb indicators to help me park next to the sidewalks close enough.

jolly_ross

Like a cat's whiskers - they tell you when you're passing cars too close.

JohnDThompson 

Too much work for too little benefit. I just let 'em wear off.

dwmckee

When you winter ride and the rubber is a lot stiffer they hold the bike upright when you stop so you do not have to lay it in the snow.

ThermionicScott 

I've generally used the more family-friendly term "tire whiskers" -- I too trim them off with a pair of flush-ground end nippers. I have to.

Nick Bain

I use a razor blade and bring them down to flush.

woodcraft

In metal casting, the channel that the molten metal flows through, into the mold, is called a 'sprue'.

Kimmo

It's also the name of the little frame that holds all the plastic parts of a model kit together.

SJX426 

The sprue is where the material enters. The flashing is where the material leaks out of the mold including the vents. You really take the time to clip them off? I would rather ride!

digibud

I chew them off. Taste like licorice.