Bicycle tires: how and what to choose?

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Depending on how you intend to use your bicycle you need to suit tires to your riding style. For example, if you are a city rider you won’t really need knobby tires but rather some slick ones as they provide a higher rolling speed.

This article presents various types of tires depending on the type on bicycle and while we also take a look at their structure. We also offer you a glossary of terms regarding each number marked on the tire.

Tire types and sizes

Tires are divided into several categories: mountain bike, road, track, BMX and city tires. A tire size matches the size of the wheel to be mounted. Thus, among the most common tire sizes we mention 16, 20, 24, 26, 27.5 (new), 28 and 29 inches tires. If the first two sizes are used for children, BMX or folding bicycles, the rest of the sizes can be seen on mountain, road or city bikes.

Construction

In terms of construction bicycle tires are divided into Kevlar bead tires and wire bead tires. Kevlar bead are folding tires, they weigh less but are also more expensive. Also, don’t forget that they are very easy to mount and dismount from the wheel. Wire bead can usually be found on cheaper tires as they require an additional reinforcement of the side walls, with the effect of a stronger grip to the rim.

Tubeless bicycle tires

Mountain tires with Kevlar bead can also be tubeless. Same as in the automotive industry UST bicycle tires (where UST is the acronym for Universal System Tubeless) can be installed without requiring an inner air tube. To benefit from such tire you will need a particular type of rim together with sealing fluid introduced into tire to fix it to the rim. Tubeless tires come with a few advantages as they eliminate snakebite flats (when the air tube gets caught between a solid object and the rim) and are also lighter as the lack of the inner tube saves dozens maybe even hundreds of grams.

Road tires

Road bicycles use either clincher tires (folding or not) or tubular tires, seen as the pinnacle in terms of things that can fit the wheel of a road bicycle. Their construction is quite simple: the tube is sewn inside the outer shell, which results in significant weight savings. Moreover, the tube is often made from latex, which makes it incredibly light and reduces the friction between it and the outer shell, the final result being an important drag reduction.

Road tires are not particularly wide, as the most generous size does not exceed 28 mm. However, any model with a minimum size of 23 mm should be able to provide a comfortable cycling.  Also, it’s worth mentioning that road tires may be designed for dry or wet conditions.

Off-road tires

If you’re riding on tough terrain then you’ll need a set of knobby tires. Some manufacturers offer tires special designed for dry surfaces, different from those meant to be ridden on mud which have a bigger distances between knobs. If you use your mountain bike mainly on paved roads, it’s better to take into account purchasing a set of slick tires, as they give you very good rolling speed, while decreasing your pedaling effort.

For cyclocross bikes sizing is the same as for road tires, but you must be careful to search for a knobby pattern.

Winter Tires

Those who cannot give up cycling even during winter can purchase a set of tires with metal studs, as they add extra grip on those slippery icy roads. .

In brief, how do I choose a tire?

Always judge according to your real cycling needs. The same tire can be sold at quite different prices, even with same pattern and this is because many manufacturers offer different versions of the same tire. Thus, a wire bead tire is cheaper and heavier than the same folding tire with Kevlar bead. More expensive tires offer several advantages, such as low rolling resistance, superior rubber mixture, lower weight and better traction but can wear out faster than cheap ones and sometime fail to provide effective puncture protection.

You must also take into account that a good set of tires decreases considerable weight from your bike. For example, a Schwalbe Black Shark tire weighs 820 grams, while Schwalbe Racing Ralph weighs 495 grams, from the same size of 26 x 2.2. And a difference of 2 x 325 grams represents a saving of 650 grams which is significant to the total mass of the bicycle.

How to choose the width of a tire?

A wider tire provides better stability once taken off-road, but in most cases this comes with the price of extra-weight. For mountain trails or XC/marathon races a tire between 2.10 – 2.25 is quite sufficient while for difficult descents, enduro and all-mountain, you need wider tires, such as 2.30 – 2.40 ones.

Mud tires are usually narrow to so they can easily move forward in rough terrain.

For riding into town, a 1.50 – 2.00 tire will do a good job when it comes to quickly moving from one place to another. And if you want something more comfortable, you can call on slick tires, however these should not exceed 2.30.

Glossary of terms

TPI

Threads per inch – This characteristic of a tire relates to the material from which it is made, a cloth of nylon most often. This is placed in parallel fibers, forming several plies and a layer of rubber is added as a contact surface with the road. A tire needs several layers of plies, each layer being placed perpendicular on the direction of the previous layer.

However, these fibers making up the “heart” of the tire are themselves composed of multiple threads. And hence, we get to the term of threads per inch (TPI). This variable specifies how many threads are in a fiber forming the main structure of the tire and therefore how much that particular tire has to offer. More threads means that the tire is more flexible, offers a higher rolling speed and saves weight as in more threads require less plies for tire manufacture.

Typically, Enduro, Freeride and Downhill tires have 60 TPI while XC and Marathon tires have 127 TPI.

PSI/BAR

These two variables refer to the pressure at which a tire must be inflated. All tires have stamped on their wall the inflation pressure, both in PSI (pounds per inch, 1 atmosphere = 14.69 PSI) and BAR (Bari, 1 bar = 0.98 atm). A tire must be inflated to the recommended pressure as too little pressure results in an increased rolling resistance and exposure to punctures, while too much pressure leads to an increased risk of damaging the tire when it comes in contact with stones or other obstacles. Riding also becomes very uncomfortable, as tires lose their abilities of absorbing shocks.

Tire Size

It refers both to tire circumference and tire width. For example, if a tire has dimensions of 26 x 2.125, then its diameter is 26 inches and width is 2.125. It is vital to know the circumference as this one has to match the wheel dimension. As for the width, it can vary widely, regardless of wheel circumference.

According to ETRTO, European standards, tires have stamped on their bead the width and their interior diameter, measured in millimeters, in our case, 62-559.

Tubeless (UST)

The UST or tubeless tires, were developed by Mavic together with Hutchinson and with Michelin. The interior coating of the rim has a very smooth surface so that air cannot leak. Of course, both rim and tire must be UST compatible. After being inflated, tire edges strongly push the rim, closing this airtight system.

Apex

While describing TPI we mentioned the plies composing tire resistance structure. Apex is nothing else but a piece of fabric which is inserted on the sides of this structure to increase the resistance of the entire tire which benefits from extra protection in case of a snakebite.

Shore

This refers to the rubber characteristics as a contact surface with the road. Softer rubber has a higher rolling resistance, so it doesn’t offer too much speed and wears fast. Therefore, many manufacturers use double or triple compounds in order to provide different mixtures for rolling surface and side walls. At the other extreme a hard tire rolls fast and it is wear resistant. However it does not provide a good grip on rocks, wet or other various surfaces. You can test for your self the softness of tire rubber is to jab it with a needle. The more easily the needle pierces the tire, the softer the tire is.

Compound

After the resistance structure of the tire has been produced, rubber is glued to it, as the contact with the road surface. Rubber may have the same texture throughout the entire rolling surface (single compound) or can be soft or harder for this surface the middle (dual compound, triple compound) to make the tire either run easier or be more resistant to wear.

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