Tires can drastically affect your ride, they can be the difference between winning or losing, crashing or “saving it,” riding with confidence or with fear. If your bike is due for a new set of tires, you should look at it as an opportunity to improve your ride. With the exception of a handful of brands, most bikes come equipped with middle-of-the-road tires that are designed to satisfy the broadest customer base. Switching to tires that fit your specific terrain and style of riding can revolutionize your ride.
Tires are the most cost effective upgrade you can make to your bike: they are comparatively inexpensive when compared to the cost of the bike and most components that go onto it, yet can have a drastic impact on the speed, comfort, grip and handling. They can also limit the amount of time spent on the side of the road or trail repairing punctures. Unfortunately there’s no one magic tire that fits all requirements, tire selection is largely a compromise: if you prioritize a particular quality or feature, you are most likely trading in another. For instance, a fast, soft, grippy tire may actually be prone to puncture, while puncture resistant tires have higher rolling resistance, making them slower. Instead of telling you which specific tire to buy, we’ll arm you with enough information to make an educated purchasing decision.
Intended Use
Different cycling disciplines, such as road biking, mountain biking, gravel biking, and city commuting require different types of tires. It is important to choose a tire that is designed for your specific type of riding to optimize performance, safety, and comfort.
Not all bicycle tires are compatible with every bike. It is essential to choose a tire that fits the rim of the wheel and clears your bike’s frame. Using an incompatible tire can negatively affect the bike's performance and lead to safety issues.
If you plan on riding in extreme weather, such as below freezing temperatures, snowy and/or icy conditions, you might need a separate winter tire set. These tires are optimized for winter temperatures and road or trail conditions that gives them a huge advantage over their summer counterparts.
Tire size
Bicycle tires come in a range of sizes, and it is essential to choose the right size for your bike. When discussing tire sizes, it’s important to consider both the diameter and width. Common bicycle tire diameters are 700C (700 mm), 29er (29 inches), 650b (27.5 inches), 26”, and 24”. While there’s a range of acceptable widths for a specific rim, the diameter is specific to the wheel that’s already on your bike. The size is typically printed on the sidewall of the tire and consists of two numbers that indicate the tire's diameter and width. These markings will look like this: “700x32c”, “26×1.95”, or “20-559”. This is the size of your tire, where the first number is the diameter and the second number is the width. Tire widths vary greatly depending on their intended design: road tires can be as narrow as 23 mm and mountain bike tires as wide as 4 inches (102 mm).
Be that comfort, grip or speed, by experimenting with tire widths and pressures, you can dial-in the desired characteristics into your ride. There are safe limits to tire widths for a specific rim width. Before changing the tire width, consult both the wheel manufacturer recommendations and the frame’s limits. Beware that the tire that will fit on your wheel might not clear the chain stays or the fork. It may also flex enough to run the frame under load. A wide tire on a narrow rim may become distorted, create an aerodynamic penalty, or even become unsafe, while a too narrow tire on a wide rim will expose the rim to damage. Refer to the tables below for the industry accepted rim/tire ranges. Note that all rim widths are internal, shown as 21 and 22.5 on the diagram below:
Tread pattern
The tread pattern on a bicycle tire determines its grip and performance on various surfaces and conditions. The tread size and pattern are always optimized for the intended terrain. Tires designed for hard surfaces, such pavement, or even the wood planks of a velodrome, have minimal if no tread at all, mostly limited to water channels to prevent hydroplaning.
Tires designed for mixed terrain and off road will have knobbies of various sizes and arranged in patterns specific to the purpose. Designed for gravel and hard pack riding, tires will have smaller knobbies with a tight pattern to optimize for rolling resistance, and might have larger side knobbies to provide extra traction when cornering.
Large knobbies are designed to dig into loose surfaces such as mud or sand to provide traction. Tight patterns perform best in dry conditions while spaced out knobbies will shed mud and will perform best in wet conditions.
Bike tires, regardless of whether they're meant for on-road or off-road use, may include a supplementary layer known as a 'sub-tread.' This additional layer, typically composed of Kevlar or nylon, is inserted underneath the main tread to enhance puncture resistance. Nevertheless, incorporating this sub-layer results in added weight and increased rolling resistance.
Other than traction, tread also affects the rolling resistance. The tire will roll faster on the surface it was designed for: smoother tires roll faster on pavement and have excellent traction while knobby tires will feel sluggish and provide less traction to boot. A smooth tire will be unstable offroad and will likely puncture and fail very quickly.
Tire tread becomes especially important if you’re riding in variable conditions. A slick tire will perform great on dry pavement, but as soon as there’s any water on the surface, the bike will become significantly less safe: the braking distance will increase tremendously and there’ll be a risk of a slide-out. Winter conditions might necessitate studded tires which offer good traction on snow and ice.
Construction
To comprehend the tire's functioning, it is critical to understand its design and composition. Although it appears as a single rubber piece on the surface, an average bicycle tire is surprisingly complex in design. It comprises three primary components: bead, casing, and tread. Each part, from the bead to the casing and tread, contributes to the tire's overall performance, and the whole is greater than the sum of its parts.
Bead
Every tire begins with a backbone, known as the bead, that is used to secure the tire to the rim and also acts as the main support structure for the tire. Tire bead is made out of a continuous strand of a very strong material, such as Kevlar. For situations where there’s a risk of the tire coming off the rim under very aggressive riding, such as in downhill mountain biking, a steel wire is used instead. Since synthetic materials are flexible, tires that use them for the bead are known as “folding” so they can literally be folded for storage. The steel bead has very little flex, making tires that use it “non-folding.” The folding bead makes tires slightly lighter and also much easier to install.
Casing
A bike tire's structure consists of a fabric network, typically made of nylon or other synthetic fibers (but sometimes cotton or silk in specific tire models), which is woven between the two beads. Unlike regular cloth that uses crossed threads, the threads in a bike tire's carcass are arranged in parallel layers, each running perpendicularly to the next at a 45-degree angle.
The layering and 45-degree angle application of the casing mesh, when attached to the rubber tread, are crucial in providing stability to a bicycle tire. Additionally, the density of the materials utilized in the casing mesh can greatly affect the tire's characteristics.
The density of the casing mesh is typically measured in "threads per inch" (TPI), referring to the number of threads contained in one square inch of casing. Bicycle tires with lower TPI counts typically have larger gauge threading and more rubber in their casing mesh, resulting in heavier weights. Conversely, tires with higher TPI have finer thread and a tighter weave in their casing mesh. Increasing the thread count results in a tire that feels more supple and flexible, leading to enhanced ride quality, handling, and control but at the cost of durability and sidewall stiffness.
Compound
The compound of a bicycle tire is important because it affects characteristics such as grip, durability, rolling resistance, and puncture resistance. Tire compounds are formulated with various blends of rubber to achieve optimal levels of grip and durability. Softer compounds provide more grip, but wear out faster, while harder compounds are more durable but provide less grip.
By combining multiple compounds tire manufacturers attempt to offer tires that offer softer rubber on the contact patch and harder rubber between the tread and casing, which results in better performance in almost any terrain.
The choice of tire compound will depend on the intended use. For example, a tire designed for racing or high-performance riding may use a softer compound to provide maximum grip and reduce the rolling resistance, while a tire designed for commuting or touring may use a harder compound to improve durability on and off road.
During the manufacturing process, the tread rubber is extruded through a die to create a thicker center and thinner sidewalls (the section between the tread and the bead) since it endures the highest amount of wear.
Tubes vs Tubeless
Most conventional bicycle tires contain an inner tube. Inner tubes are cheap, readily available and are relatively easy to replace. Unfortunately, just like everything else when it comes to tires, tubes come with a hefty set of drawbacks: they are susceptible to punctures, require a certain minimal tire pressure to perform correctly, and increase the rolling resistance.
Tubeless tires are omnipresent in cars and have been popular with the mountain biking community for decades. Instead of the inner tube, these tires contain a liquid sealant. Tubeless tire sealant is typically made from a mixture of liquid latex and other ingredients such as small rubber particles, fibers, and proprietary compounds. The liquid latex is the primary ingredient that coats the inside of the tire and seals any punctures that occur while riding. The rubber particles and fibers help to create a mechanical plug that fills the hole and keeps the sealant in place.
Running your tires tubeless has a number of advantages: they are a lot less prone to punctures, have lower rolling resistance, and can offer better traction because they can be run at lower pressure without the risk of pinch flats. If you were to puncture a tubeless tire, you could always install a tube to get you home, or use a tubeless tire repair kit to seal the picture with a plug.
Tire Inserts
There are situations where traction is more desirable than low rolling resistance, such as that in mountain biking where hard cornering at speed is a common occurrence. Additional traction can be easily found by lowering the tire pressure but if lowered too much, the tire will become unstable, can roll off the rim and you’ll be at risk of damaging the rim on a rock.
Tire inserts are made from high-density foam and are installed inside the tire, sitting flush against the rim and the sidewalls. Most inserts weigh only slightly more than a comparable inner tube, but provide a number of advantages.
Tire inserts can prevent punctures by providing an additional layer of protection between the rim and the riding surface. They increase sidewall stiffness and reduce lateral roll, which improves high-speed cornering, even at a significantly lower tire pressure. The inserts also absorb shocks and vibrations, acting as suspension, but are known to make the tire feel less bouncy. Tire inserts are only compatible with tubeless tires.
Solid Core Tires
Solid tires, also known as airless tires, have existed for many years. These tires contain no tubes, the void where the tube would go is filled with rubber. They do not need to be pumped and will never go flat. Until the recent advancements in technology, they have been slow, heavy, uncomfortable and lacking in grip. In the last decade, the technology that goes into these tires has improved significantly. The recent models of airless tires are made out of advanced blends of rubber that trap many air bubbles, creating a compound known as cellular rubber. The compound’s properties are tuned for optimal bicycle tire performance.
While the airless tires suffer from such shortcomings such a higher rolling resistance and inability to adjust pressure, they provide worry-free cycling for situations where puncture resistance is of the utmost importance. These tires are optimal for bike commuters, students, and environmentally cautious cyclists who picked cycling over driving.
Tire Pressure
A conversation about tires would not be complete without a discussion of tire pressure because running tires at the right pressure is almost as important as having the right tire. Tire pressure affects not only how comfortable your ride is, but it is also a matter of safety. Low tire pressure can make the ride squishy, requiring extra effort to pedal and increases a chance of a rim strike, which could result in wheel damage. High tire pressure can make your ride feel jarring, and while it will roll faster, the stopping distance will increase and grip may diminish.
Changing the tire pressure has a significant impact on the vibrations that are felt through your bike and through you. By experimenting with tire pressure you can find the sweet spot between speed and comfort.
Unfortunately, there’s no magic formula for setting the optimal tire pressure, because it depends on so many factors such as the rider’s weight, bike type, terrain, tire volume and construction. The best way to determine the optimal pressure is empirically, by making small adjustments and observing how they affect the ride.