Features
The general purpose of tyres determines the type of bike and the general riding style they are designed for. Of course, this indicator is rather conditional, and in each category there are separate varieties that can differ markedly in characteristics. However, within each appointment, there are inevitably common features.
It is also worth noting that among tyres for different purposes there may be identical models in size, and it is technically quite possible to install non-native products on a bicycle. However, it is still not recommended to do this: matching in size does not mean that the performance of the tyre is suitable for a specific riding format. For example, there are a lot of 26" options among urban/tourist models, but when installed on an MTB, such tyres most likely will not provide normal grip for riding on rough terrain.
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Urban/tourist. This class of tyres can be conditionally described as "walking". They are designed for driving mainly in uncomplicated conditions, at low speeds on hard and relatively even surfaces (for example, asphalt or rolled dirt roads). Note that this category includes two main types of tyres — for adult bicycles and for children. "Adult" models mostly have a rather large size — from 26 "and in most cases 28". This, in particular, allows you to keep the speed well and coast for a long time. The diameter of "children's" tyres, respectively, is smaller — depending on the age categor
...y of the bike. However, both of them have a tread with a pronounced, but shallow relief, which allows you to maintain sufficient grip on asphalt and on less favorable surfaces (although off-road driving is usually out of the question).
— Mountain (MTB). "Mountain" riding involves off-road driving, often on difficult surfaces like sand, mud or small gravel. In addition, the wheel must provide good torque, but speed performance and coasting are not particularly important in this case. As a result, mountain bike wheels and tyres are somewhat smaller than touring/city bikes: in this case, the “classic of the genre” is considered to be a diameter of 26". At the same time, there are also larger models — 28" and 29"; note that they have the same inner diameter of 622 mm and differ only in profile height.Such "larger" tyres are usually positioned as off-road models with a larger footprint, better handling in mud and sand, and more stable in corners.There are also children's MTB tyres — they are correspondingly smaller in size than "adults".
— Highway. Tyres designed for driving on roads with even hard surface — including during the races. With such movement, high speed and the ability to coast for a long time are more important than acceleration, so road tyres are quite large — usually 28". road bikes).
— Stunt (BMX). Tyres for stunt riding associated with the performance of various acrobatic numbers — jumps, slides, etc. To ensure good acceleration dynamics and torque, bicycles of this type have small wheels — usually about 20 "; this is the size that is considered standard in this case. However, "bicycle acrobatics" includes many subspecies, and other sizes will be optimal for some of them. As a result, among such tyres there are models for both 16 "and 26".
— Electric bicycles. Tyres specially designed for e-bikes. In terms of application features, such machines are generally similar to urban / tourist ones (see above), however, there is one important nuance: electric bicycles move much faster. So, if an ordinary bike only occasionally and briefly reaches speeds of 40 – 50 km/h, then for many electric bikes such a high-speed mode is standard. Thus, such vehicles require special tyres — capable of maintaining performance even at high speeds, as well as having good grip for safe cornering.Width
The nominal width of a tyre, in fact, is its width with a normally inflated wheel. Approximately this parameter is expressed in inches, more precisely - in millimeters. The latter option is used in bicycle tyres marked according to the “French size” (see the corresponding paragraph).
As well as the fit size (see "ETRTO Standard"), this indicator determines the compatibility of a tyre with a particular rim. However, if the size must exactly match the size of the rim, then in the case of the width, the selection rules are somewhat different. It doesn't have to exactly match the inside width of the rim - a tyre that is 1.5 to 2 times as wide is considered the best option. Up to 2.5 times is allowed, but care must be taken here: a tyre that is too wide on a narrow rim will behave worse in corners and may break off the rim. Also, excessive width impairs handling at low speed and with a pressure drop (even a small one), accelerates sidewall wear. In turn, a tyre that is too narrow is more likely to puncture and damage the rim due to abnormal loads on it.
Recall that if the marking of the tyre matches the marking of the standard tyres of the bicycle, it is guaranteed to fit it. This is true for width as well. At the same time, there are tables that allow you to determine what "non-native" tyre width is suitable for a particular rim.
ETRTO
The main dimensions of the tyre are in accordance with the ETRTO standard (the name "ISO standard" is also found). Indicated in millimetres, while the first digit corresponds to the width of the tyre, the second to the inner diameter.
The variety of markings used for bicycle tyres (including french size
650x23C,
650x25C,
650x28C,
650x35C,
650x43C,
650x48C,
650x54C,
700x20C,
700x22C,
700x23C,
700x25C,
700x26C,
700x28C,
700x30C,
700x31C,
700x32C,
700x33C,
700x34C,
700x35C,
700x38C,
700x40C,
700x42C,
700x43C,
700x45C,
700x47C,
700x50C) at one time created many problems for both users and specialists.
...Moreover, in most cases, inches were used for marking, and this is a less accurate unit of measurement than millimetres. Moreover, formally identical sizes with different designation formats often differed in fact — for example, 1.75 "and 1 3/4" inches could correspond to different actual sizes in millimetres. Also, manufacturers most often indicated in the characteristics the outer diameter of the tyre, and not the inner one, and without actual fitting it was far from always possible to choose a product to fit the rim size.
To remedy the situation, the ETRTO (ISO) standard was developed. Dimensions according to this standard are perhaps the most important parameter for selecting a bicycle tyre. First, ETRTO covers the two main characteristics that determine rim compatibility — bore diameter and width. See above for the meaning of width; and the tyre and rim must match in terms of the rim diameter — otherwise the installation will be simply impossible, no matter how perfect the other characteristics of the “rubber” may be. Secondly, ETRTO uses a designation in millimetres, which allows you to choose the tyre size with maximum accuracy.
There are tables that allow you to translate some branded "inch" markings into ETRTO values; such tables can be found in special sources. However, the need for such data rarely arises: most modern manufacturers, along with branding, also use the ETRTO standard.EPI (TPI)
The carcass density of the tyre in threads per inch (Ends Per Inch or Threads Per Inch).
The material of a bicycle tyre is composite in composition, it includes a beading cable (see below), a frame (cord) made of synthetic fabric, and rubber itself (compound). The density of the frame determines primarily the softness of the product; dynamics, rolling, cross-country ability and a tendency to crush when hitting obstacles and other heavy loads depend on this. So, a soft cord is better suited for driving over rough terrain, including on difficult surfaces like sand or gravel: it provides a larger contact patch, crumple well on small bumps and allows you not to lose speed when hitting a small obstacle like a pit, tree root, etc. Yes, and it shakes on such tyres less than on hard ones. On the other hand, they hold speed and roll worse, and also have an increased likelihood of punctures in certain situations: for example, a sharp stone can dent the tyre to the very rim and pierce the chamber.
Hard tyres, in turn, are distinguished by good dynamics: it is easier for them to pick up speed and maintain it. Yes, and when hitting the same sharp stone, the probability of a puncture will be much lower. On the other hand, the slightest obstacle on the road when driving on such tyres will lead to a noticeable loss of speed, and on uneven surfaces the bike will be subject to strong shaking. In addition, from a certain value (120 EPI and above), an increase in the dens...ity of the carcass does not increase, but a decrease in reliability: a high density of threads leads to a decrease in their thickness and, accordingly, strength.
Also recall that the actual stiffness of the wheel will depend not only on the carcass, but also on the pressure in the tyre. So in some situations, the features of the frame can be completely compensated for by selecting the appropriate pressure.
If we talk about specific numbers, then tyres with a cord density of up to 60 EPI (TPI) can be classified as soft, up to 90 TPI — as medium, up to 120 — as hard, and a value of more than 120 EPI (TPI) corresponds to high rigidity. With the above in mind, soft tyres are better suited for rough terrain and stunt riding, while hard tyres are better for high-speed driving on flat roads. More detailed recommendations on this matter can be found in special sources.
Cord
The material of the bead wires used in the tyre.
A beading cable is a rigid cable passed along the edge of the tyre (along that part of it that is in direct contact with the rim. It allows the tyre to maintain its shape and provides it with a snug fit to the rim. Such an element can be made from different materials:
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Steel. A steel wire beading cable is a classic and most common option in modern models. This design is quite practical and at the same time inexpensive. It does not have some of the advantages of Kevlar (see below), but in most cases this is not critical.
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Kevlar. Kevlar fibre is lighter than steel wire, resulting in an average weight gain of about 100 grams per tyre. It is this option, for a number of reasons, that is considered optimal for tubeless models (see below). In addition, it allows you to fold the tyre very compactly (literally “flatten” it) without losing performance. Therefore, models with such cables are sometimes also called "folding". However, they are much more expensive than tyres with traditional materials.
Puncture protection
The presence of additional
protection against punctures in the design of the tyre.
Such protection is a layer of special material (dense rubber, Kevlar, etc.) placed between the cord and the tread, thereby increasing the total thickness of the tyre from the outer part of the tread to the chamber. As a result, many small sharp objects (like a carnation or glass shard) that could pierce a normal tyre do not pose a danger to a protected model. Of course, this design does not give an absolute guarantee against punctures, moreover, the additional layer usually does not apply to the sidewalls; however, other things being equal, “protected” tyres are definitely more reliable than unprotected ones. Their unequivocal disadvantages include a higher cost, as well as a slightly greater weight.
Weight
The total weight of the tyre.
This indicator affects the overall weight of the bike, but this influence is so insignificant that in most cases it can be neglected — especially since the difference between tyres similar in size and use can be some tens of grams, or even grams. In fact, paying attention to weight makes sense mainly when used in professional racing, where the struggle sometimes goes for tenths of a second — and, accordingly, every extra gram can be decisive. If tyres are bought for simpler use — for example, amateur "rides" on roads or even cross-country — this parameter can not be given much attention.