Tires 101: Come to Grips With One of Your Bike’s Most Important Components

At first glance, tires may just be one of the most boring components on a bicycle. If you happen to agree with that statement however, you’re forgiven. Now that you’re here, we can set things straight. Far from boring, tires are instead one of the most truly impressive components to grace your bike.

From the road tire tasked with keeping a cyclist connected to twisting roads at 50-miles-an-hour with a contact patch that boasts less surface area than a quarter, to a mountain bike tire subjected to death-defying jumps and rock drops, it’s safe to say that tires are far from boring, instead embodying attributes that border on black magic—ask a derailleur to do something even half as impressive and you’ll be sorely disappointed.

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John Dunlop’s beard is almost as impressive as his inventive spirit.

First produced in 1887, by John Dunlop, the pneumatic tire was the beginning of a long march of advancement for the bicycle. Pneumatic tires not only made riding a bicycle a much more comfortable proposition, it opened up a whole new world of performance capabilities as well.

Dunlop’s first tire took the form of what we now refer to as a tubular tire, and consisted of a rubber inner-tube encased by a soft, pliable woven-cotton casing over the top half of which, a layer of rubber tread was applied.

The next major advancement in tire history occurred with the invention of the clincher tire. Named for its key design aspect, a bead that was clenched in place by a combination of a specially designed rim and the inflated inner tube, it drastically simplified flat repair and tire replacement, making the bike an even more practical mode of transportation.

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While still used almost exclusively in the pro peloton, the tubular has fallen out of favor in casual use, with most preferring the much more practical clincher design.

While both varieties are still in use today, we’ll be focusing on the more common of the two, the clincher.

All clincher tires share three essential parts in common: a bead, a casing, and tread.

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This folding bead uses many threads of aramid fiber to keep the tire in place on the rim.

Bead: Tasked with keeping the tire on the rim, you might say the bead is a pretty important part of a tire’s makeup. Requiring a material that stretches very little, most beads are constructed out of either wire, aramid (a family of nylon fibers that includes Kevlar), or carbon fiber. Wire beads are found on most budget-oriented tires and are much heavier than their aramid counterparts, which are often referred to as ‘folding beads’ due to their more flexible nature. Carbon beads also are foldable and are typically found on road tubeless tires.

casing

This casing ply will be layered with several others before being mated to a layer of tread.

Casing: Tasked with giving the tire it’s shape, the casing is the foundation of the tire. It must be strong enough to withstand the necessary air pressure, but it must also be supple enough to provide proper grip by deforming on the road or trail’s surface. Originally comprised of woven cotton, most tires now use nylon for its superior strength. Generally, the higher the thread count of the casing, the more supple the tire feels.

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While most road tires are slick to reduce rolling resistance and maximize the tire’s contact patch, tread design plays a large part in determining a mountain bike tire’s handling characteristics and varies greatly from tire to tire.

Tread: The most visible part of the tire, the tread is responsible for providing the tire with both grip and protection. Comprised of butyl rubber, proprietary additives are often added to influence a number of important variables including: grip, longevity, and protection.

Extra Credit Vocab:
Sidewall: Technically still part of the casing, the term sidewall refers to the exposed section of the sidewall in between the tire’s bead and the edge of the tread.

Breaker: Composed usually of hard plastic or very tightly woven and reinforced nylon, a breaker layer is often placed in-between the casing and the tread in order to improve the tire’s puncture resistance.

Tubeless: A sub-group of the clincher family, tubeless tires are designed to be used without inner tubes (bet you couldn’t have ever guessed that one!). Requiring a special rim, the bead on tubeless tires creates an airtight seal so that air may be pumped directly into the tire. Liquid sealant is often placed within the tire to aid the bead in sealing with the rim as well as seal any punctures that may occur.

2015-12-16T17:10:54-08:00