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Tires: More to them than you think

by Ian Lurie, Portent Interactive.

When it comes to a bicycle, a tire is a tire, right? Wrong. These days, bicycle tires are as high tech as the latest computers. And the right or wrong tire choice can make or ruin a racer's day. Weather, course and competition all affect tire choices.

A cyclist depends on a tiny patch of their tires - usually less than a square inch - for traction, speed and shock absorption. Different tires offer different advantages, but all tires have a few basic components:

Tread. The pattern of grooves on the tire, or tread, helps the tire shed water, dirt and other debris. But a larger tread offers more rolling resistance and slows the racer down. Look for the riders in the time trials to use nearly-slick tires for the fastest possible ride.

Casing. The side of the tire, or casing, defends the tire against sharp rocks or other debris that may slice the side of the tire. It also offers most of the shock absorption. A lighter casing means a lighter, faster wheel with better shock absorption, but is also more vulnerable to cuts.

Bead. The bead holds a conventional clincher tire on the rim. Beads can be made of wire, kevlar or other materials. A kevlar bead is super-light, but installing a tire with a kevlar bead leaves you cursing with sore fingers. But hey, the pros have mechanics to handle it. Any racer riding clincher rims will use a kevlar-beaded tire.

Belt. A kevlar belt helps tires defend against flats. I've ridden kevlar-belted tires right over broken glass without a single flat. But these tires are heavier and roll more slowly. They also have almost zero shock absorption. Still, some racers may choose to use the best kevlar-belted tires on longer days, if they think the course will be messy.

Tube. While conventional clincher rims use a separate tube, tubular or sew-up wheels use tires that have the tube sewn inside the tire. These are very, very fast wheels. On both clinchers and sew-ups, the tube can add or subtract a few grams to the overall rotating weight. So riders usually opt for the lightest practical tube

Air Pressure. Some tires can hold more air than others. Most racing tires hold between 100 and 140 pounds per square inch. A tire with less air provides a more comfortable ride, and better traction. A tire with higher air pressure is fast, but can feel like you're riding on boulders.

There's a lot more to tires, believe me. Threads per inch, mounting and exotic materials abound. But the goal never changes: Select the equipment that'll keep you upright and fast.

Questions? Did I miss something? E-mail Ian Lurie at ianATportentinteractive.com. That's not a typo - I don't like spam any more than you do. Replace the AT with an @ symbol and your message will reach me, I promise.