Tires (Clinchers)

You’ve heard  it’s harder to find 650c wheels and tires.  Was the source of that information someone who has never had to work at finding clothes that fit, or a small enough car with a steering wheel they can actually see over the top of?  The vertically challenged are used to just that–challenge!   So congratulations for ignoring your “source.”

Now it’s time to learn about tires. There are three types:  Sew-ups, tubeless and clinchers.

Clinchers are attached to the wheel by a metal bead on the edges of the tire that hook over the edges of the rim of the wheel.  The bead can be made of steel or Kevlar® cord.  Tires with steel beads cannot be folded.

Rubber is used to coat and protect fabric (made of nylon or other polyamides), which is woven from one bead to the other to create the shape of the tire.

The threads are not interwoven like traditional cloth, but are  parallel fibers placed in layers on a bias, with each layer running perpendicular to the next.  The type of thread (thin or thick) used to create the fabric determines its ” TPI” or threads per inch.

Compare this to the thread count of sheets. High thread count in sheets make them softer, but they tend to wear out quicker.  The higher the TPI, the thinner, lighter and more flexible the tire fabric is.  Some consider this number representative of a tire’s performance, claiming that the higher the number the lower the rolling resistance.  Unfortunately, a higher the number also means tires are more easily damaged by road hazards.

The rubber that comes in contact with the road is called the tread and is significantly thicker than the sides of the tire. Some treads have patterns which may enhance traction, others used for racing, are slick and do not have any pattern. Manufacturers produce different formulations of rubber to achieve varied traction and wear properties. Better traction may mean faster wear.

These tires require an inner tube.  Air pressure in the inner tube is what seals them in place. 99% of the tires produced are clinchers and are considered normal road tires.  

Sew-ups (also known as tubular tires)  have the tire and inner tube combined.  They are used primarily for racing and do not have a bead but instead require adhesive glue or tape to attach to the wheel rim. Hmm… I can’t imagine flying down a hill at 35 mph with my tires held on to my wheels with… glue?

Tubeless tires are a fairly new invention which was initially designed for mountain biking and tend to minimize the occurrence of pinch flats.  This type of tire is a scaled down version of an automobile tire.  As their name implies, tubeless tires do not require an inner tube (obviously).