Frame size
Frame size refers to the distance from the saddle attachment point to the bottom bracket attachment point (axles with gears and pedals). The main parameters that determine the choice of a bike for frame size are the height of the user, the purpose of the bike and the intended riding style.It is also worth considering the
female frame, which is lowered, which allows you to ride comfortably even in a skirt or dress.
User height is the most significant factor. In general, the taller the user, the larger the frame should be. The universal formula that allows you to calculate a specific size is as follows: the length of the leg from the groin to the heel in centimeters must be multiplied by 0.6, and then divided by 2.5 — you get the approximate size of the frame in inches. But in the characteristics of brands, the frame can also be indicated in the usual form for measuring size
XXS,
XS,
S,
M,
L,
XL and
XXL.
However, note that this value is very arbitrary and approximate, it can only be used for simple bicycles not intended for extreme driving (for example, city bikes, see "Destination"). If you choose a more specialized model (mountain, road, BMX) — it is better to refer to the tables for th
...e appropriate type, because. sizes for one height can vary significantly depending on the destination. In addition, different manufacturers have different frame geometry and measurement methods, and therefore, for the most accurate selection, it is recommended to use the manufacturers' own tables.
Note that the optimal frame size is not absolute — in most cases, for the same height, “neighboring” sizes are quite suitable. And here it is worth paying attention to the intended driving style. It is believed that small, well-controlled frames are better suited for extreme variant, and larger and more stable ones are better suited for long-term calm movement.Front brake
The type of brake fitted to the front wheel of a bicycle. The first word in the name of the brake indicates the place of application of the braking force, the second — the design feature of the entire braking system.
—
Rim (V-brake). Rim brakes are called brakes that work by pressing the brake pads against the wheel rim. They transfer the braking force from the handle to the pads by means of a cable pull. The common advantages of all rim brakes are the simplicity of design, light weight, low cost, good interchangeability of parts, as well as the minimum load on the hub and spokes. On the other hand, such brakes wear out the pads and rim, require periodic adjustment, and lose effectiveness when the rim is dirty, iced or warped.
Structurally, the differences between the subtypes of rim brakes lie in the way they are attached to the bicycle frame. In addition, each variety has found its own scope. So, V‒brake is common in teenage, touring and budget mountain bikes, the clamp subtype has found its way into road and city bikes, and the U-brake is practiced in BMX bikes.
— Disk mechanical. In disc systems, braking is carried out by pressing the pads not to the wheel rim, but to a special brake disc rigidly fixed on its axis. The braking force, as in mechanical rims (see above), is transmitted to the pads through a special cable. The main advantages of disc systems are significantly more power than rim systems, as we
...ll as better modulation (for modulation, see "Rim hydraulic" above). In addition, they are less sensitive to weather conditions (because the disc is quite high and clogs less than the rim), they easily carry the “eights” on the rims, and the elements of the system wear out more slowly and are not so demanding to adjust. Among the disadvantages are greater weight, high cost, a tendency to overheat, an increase in the load on the spokes and wheel hub, as well as difficulty in repair — the last point is aggravated by the fact that different models of even one manufacturer are often not compatible in terms of spare parts. However, despite all this, disc brakes are quite widely used in extreme riding bikes, especially mid-range and high-end models.
— Disc hydraulic. A variant of disc brakes (see above), in which not a cable is used to transfer force from the handle to the pads, but a hydraulic system — a sealed structure filled with liquid and including a piston system. One of the main advantages of hydraulics is excellent modulation, it allows you to very accurately control the braking force. On the other hand, such a drive is more complicated and more expensive than a mechanical one, and if the circuit is damaged and the hydraulic fluid leaks, the brakes become useless. Therefore, hydraulic systems are used relatively rarely, mainly in professional bicycles.
— Drum. Brakes using a special drum, inside which brake pads are installed; in bicycles, the role of the drum can be played directly by the wheel hub or a special part of the hub. Anyway, the pads are pressed against the drum from the inside, and the entire brake structure is closed. This is one of the main advantages of this option: the mechanism is protected from pollution, external factors such as dirt or snow practically do not affect the effectiveness of the brakes. In addition, the advantages of drum mechanisms include the fact that they practically do not require maintenance, do not wear out the rim and do not lose efficiency when it is bent. On the other hand, such brakes turn out to be quite bulky, and in terms of efficiency they are inferior to rim and even more so disc counterparts. Therefore, this option is found mainly in urban bikes.
— Roller. A variety of drum brakes (see above), in which the pressing of the brake pads to the drum is ensured by a special mechanism — roller. In this case, the brake drum is often performed separately from the bushing. Such solutions were developed as an attempt to combine the advantages of disc and drum brakes in one mechanism, and partly succeeded: roller systems are noticeably more powerful than classic drum brakes, they are well protected from dust and dirt, require virtually no maintenance and work effectively even with a curved rim. On the other hand, the weight, dimensions and price of such brakes turned out to be very significant, they worsen the roll and get quite hot with constant use; and protection against pollution is not as high quality as in drum systems.Rear hub model
Model of the hub used in the rear wheel of a bicycle. See Front Hub Model for details.
Speeds
The number of speeds (gears) provided for in the design of the bicycle. Each transfer has its own so-called gear ratio — in this case it can be described as the number of revolutions that the driven gear (rear, on the wheel) makes in one revolution of the leading gear (associated with the pedals).
Different gear ratios will be optimal for different conditions: for example, high gears provide good speed, but are poorly suited for overcoming obstacles, because. the effort on the pedals increases significantly and the frequency of their rotation decreases. It has been scientifically proven that a cyclist develops maximum power at a cadence of about 80-100 rpm. Thus, the presence in the bike of several speeds allows you to optimally adjust it to different driving modes and features of the tracks in order to provide optimal pedaling force and frequency of their rotation. For example, on smooth asphalt it is best to drive in a high gear, and when overcoming a rise or entering a dirt road, you can lower it in order to effectively overcome resistance.
The number of gears in classic systems is directly related to the number of stars of the system (on the bottom bracket with pedals) and the cassette (on the rear wheel); it can be obtained by multiplying two numbers — for example, 3 stars of the system and 6 on the cassette give 18 gears. However, there is also the so-called planetary hubs — there are stars one at a time, and gear shifting is carried out by a mec...hanism built into the rear hub.
Note that the optimal number of gears depends on the purpose of the bike (see above), and it is not always necessary to have several of them. So, in mountain models, depending on specialization, there can be from 8 to 30 gears, in road ones — within 20-30, and some inexpensive city bikes and most BMXs do not have a gear shift system at all.
Planetary hub
The presence of a planetary hub in the design of a bicycle, more precisely, the rear wheel of a bicycle.
Such a bushing is installed directly on the wheel axle; the name "planetary" describes the type of mechanism located inside. The purpose of such a sleeve is the same as that of the cassette (see below) with several sprockets: it provides gear shifting. At the same time, the cassette itself most often has one asterisk and does not participate in gear shifting (although there are exceptions where the “planetary” is supplemented by a cassette with several asterisks).
The planetary hub has both advantages and disadvantages compared to the classic multi-star cassette. One of the key advantages is the closeness of the mechanism: it is not affected by moisture and pollution, requires virtually no maintenance and, subject to the rules of use, can last a very long time. If gear shifting is carried out only due to the “planetary”, the bike does not need additional rollers for the chain and it wears out less. Also, the chain in such models is constantly in one position, which allows you to install full protection on it (and it protects not only the chain, but also the cyclist's clothes). In addition, the advantages of planetary bushings include ease of adjustment, resistance to falls on the side, ease of adjustment, ease of switching (one switch is enough) and the absence of close and “opposite” gears.
On the other
...hand, such systems are much more expensive and heavier than classical switches of similar quality; they are more difficult to repair, make it difficult to replace the wheel and adjust the gear ratios if the initial value of the latter for some reason does not suit the cyclist. Yes, and the gear ratio (the difference in speed between the lowest and highest gears) of the planetaries is noticeably lower; the exception is perhaps expensive professional bushings, and even then not all. This makes climbing steep hills difficult (the gear may not be low enough) and fast driving, where high gears are needed, including when descending. Accordingly, planetary hubs are poorly suited for hilly or rough terrain. However, the gear ratio can be increased by adding a classic derailleur (with a multi-star cassette) to the bike — however, with this addition, many of the original advantages of the "planetary" are lost, such as insensitivity to pollution and a constant position of the chain.Freewheel/cassette model
Model of a cassette — a system of rear wheel gears — mounted on a bicycle. Cassettes of different models differ in characteristics and can belong to different classes — from entry-level to professional. Knowing the cassette model, you can get acquainted with its features in more detail (according to official documentation, reviews, user reviews, etc.). This is especially important when choosing a bike for professional cycling.
Rear derailleur
Model of the derailleur (derailer) installed on the rear wheel cassette as standard on the bike. For more information on why you need to know the model of a particular bicycle component, see paragraph "Cassette Model".
Shifter type
Type of shifters — devices that control gear shifting — installed on a bicycle. To date, the following types of shifters are used:
— Trigger. The design of this type is based on the use of 1 or 2 levers, as well as (sometimes) buttons located in close proximity to the hands of the cyclist. Trigger shifters can have different designs with varying degrees of convenience (usually, this is directly related to the price category of the device), located above or below the steering wheel, however, a number of common features are characteristic of all such models. Their main advantages are the traditional design and comfort when holding the steering wheel — the shifters are located outside the handles (grips) and do not affect convenience. In addition, they are quite simple in design and installation. On the other hand, this type also has a number of disadvantages. Thus, the presence of protruding parts increases the risk of equipment failure or injury to the cyclist in an accident. In many models, especially the low-cost level, in some cases, you have to take your hand off the steering wheel to change gear, which can lead to loss of control. In addition, shifting gears more than 2-3 "clicks" per press in trigger shifters is somewhat difficult and requires skill. However, in most cases, these disadvantages do not play a decisive role, and this type of levers is by far the most popular.
— Grip shift. By design, the grip shift is somewhat reminiscent of motorcyc
...le gas regulators: part of the handle is made movable, and gear shifting is carried out by turning it in one direction or another. Since the grip shift rings are actually combined with handles (grips), you don’t need to remove your hand from the steering wheel to control the gears — just move it a little to the side, and you can switch speed (and in some cases you can even keep your hands on the rings all the time). Such systems are devoid of protruding parts, which increases reliability and safety. Another advantage over triggers is the ease of shifting gears to any number of speeds. The main disadvantage of this type is the increased risk of accidentally shifting gears on a difficult section of the track, when you have to hold on tightly to the grips (especially with large palms and short grips) — you can accidentally turn the shifter, which is fraught with a sharp shift, breaking the chain from the sprockets and loss of controllability. In addition, contact with water or dirt on the ring can lead to slippage of the hand when working with gears, and the rings themselves increase the dimensions of the steering wheel and for some may cause inconvenience in the grip.
— Dual control. An original system that combines the control of brakes and gears in one lever — the brake lever. In this case, braking is carried out by moving towards you, and gear shifting is carried out by shifting up or down. The advantages of such a system are the constancy of the grip of the steering wheel — 2 fingers are enough to control both the brakes and the gears. At the same time, dual control shifters are quite complex in design, as a result, they are expensive and poorly compatible with “non-native” brakes and switches. And the ergonomics of such systems is very ambiguous, ease of use largely depends on the individual tastes of the cyclist. Therefore, this type of shifters is rather uncommon.
— Electronic. The competitive advantages of electronic shifters include the absence of a cable and levers to transfer physical force to the switch. In fact, these are ordinary buttons that send signals to the gearshift control unit. Such shifters work in conjunction with electronic switches that are installed on board advanced bicycle models. They can be placed in any convenient place with quick and comfortable access to the switches.Shifter model
The model of the shifters (see “Shifter type”) that are fitted to the bike as standard. For more information on why you need to know the model of a particular bicycle component, see paragraph "Cassette Model".