Tread, Casing, Bead, and Inner Tubes
How to Pick the One for You
With so many manufacturers to choose from, picking the right road tire for your riding style and budget can be very confusing. Dual compound treads, Kevlar beads, Kevlar belts, the thread per inch count of casings, and all the different kinds of inner tubes can add to this confusion. So how do you decide which tire is the best one? Here are some basic guidelines to follow.
The tire tread for a road bike tire is much simpler than that of a mountain bike, but there are some important things to consider when choosing one. The tread of a road tire is often slick or has a very shallow pattern. This is for two reasons. Road bikes are made to go fast while still maintaining rolling efficiency. No tread or very little tread at all helps to reduce rolling resistance. You may ask, "What about traction?". Traction is not as much of an issue because of the narrow tire width used on a road bike. The contact area to the pavement for a road bike tire is about the size of the outline of a paper clip (per wheel). This enables the tire to press through any moisture that may reduce traction. This is the second reason for slick treads and no tread so as not to interrupt the squeegee process.
Dual compound treads are another thing to consider in choosing a road tire. If you need more confidence in cornering, many tires are available with softer rubber on the sides of the tread to give you more grip to the road when you lean your bike into a corner. Often this tread is a different color than normal black tread and many people choose the color as a way to accent their bike. It is sort of the road bike equivalent of white walls, but with a function. Of course dual compound treads will add to the price of a tire.
Road tires come as narrow as 18 mm and as wide as 45 mm (hybrid road tires). Narrow tires are for the fast tourist or the racer. Wider tires are for the gravel road rider or the loaded cross country tourist. The most common widths are 20 mm, 23 mm, 25 mm, and 28 mm. If you use a tire narrower than 20 mm, the ride is very harsh and the probability of flats from pot holes or gravel is much higher. Tires wider than 28 mm may require a special frame and brakes to give enough room to prevent the tires from rubbing.
Most road bicycles come stock with 23 mm tires. If you would like more speed, don't mind a harsher ride, and can live with the chance of more flats, try a narrower tire. If you want a cushier ride, want to reduce the chances of pinch flats, and can live with slower acceleration due to increased weight, then try a wider tire.
Casing (Side Walls)
The casing of a tire is the network of cloth that gives the tire it's shape. Nylon and cotton casings are the most common for clincher tires. The threads per inch of the casing is usually a clue to the characteristics of a tires side wall. A lower thread per inch count indicates a less expensive tire that will be heavier and give a slightly harsher ride. But this tire may be less prone to side cuts. This is because more rubber fills the cracks between the threads than on a tire that has a higher thread count. Higher thread count casings offer a smoother more supple ride, a lighter tire, but often these tires are not very forgiving on rough pavement and gravel.
The tire bead is the portion of the tire that sits inside of the rim. Tire beads are most commonly made of several strands of wire surrounded by rubber. The other less common bead is made of Kevlar surrounded by rubber. Kevlar beads are more flexible than a wire bead and are popular with tourists because a tire can be folded up more compactly to fit into panniers or bags. Kevlar beads are also popular with racing cyclist, because a Kevlar bead saves around 100 grams of rolling weight (rotating weight slows acceleration). The catch with Kevlar beads is that they usually double the price of a tire.
Puncture Resistant Belts
Belts inside of the tread of a tire made of steel or Kevlar can reduce the chances of glass or cinders from cutting into your tires. There is a weight penalty and some gain in rolling resistance from adding belts to tires. Another option for belts to reduce flats is to use a plastic or Kevlar insert between the tire and the tube. This method is more versatile in that you can use it with any tire and you can re use the tire liner after you have worn out your tires.
The most common material for road bike inner tubes is butylized rubber. You can get rubber tubes in different wall thickness. The standard width wall offers a compromise between light weight and puncture resistance. Thinner tubes offer light weight, but give a greater chance of a puncture from anything that cuts into the tire. There also is a greater chance of a flat from the thinner inner tube seeking out a hole in the tire casing or a rim hole under a misaligned rim strip. Thicker tubes offer more resistance to flats from these causes but suffer from slow acceleration due to added weight. Thicker tube also give a slightly harsher ride.
Latex and latex mixed with butyl rubber tubes are reserved for the riders who are looking for a light and resilient ride, but don't mind filling their tires more frequently. Latex inner tubes leak slightly over the course of a day. Latex tubes are also prone to flats from the same causes as a thin butyl rubber inner tube. All tubes loose air over the course of a week and tire pressure should be checked frequently.
Wipe Them Tires
After riding through gravel or glass, it is a good idea to wipe your tires lightly with your gloves. This will displace any small particles that may inch their way into your tread as you ride. Make sure that you keep your hands away from any space that may jam your fingers between your tires and your bike (the frame or the brakes). After a ride you can even pick out tiny bits of glass or cinders from the tire tread further reducing your chance of getting a flat. If you are on a mountain bike, don't wipe the tires (knobs at speed on hands = pain).
Questions or Comments Welcome