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.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.
Freewheel cogs
The number of stars (gears) of different sizes in a bicycle cassette. A cassette is a part of the rear hub that interacts directly with the chain, in other words, a gear or a set of gears mounted on the hub. In classical gear shifting systems, the number of gears directly depends on the number of stars in the cassette (for more details, see "Speeds"); a single chainring is used either in single speed bikes or in planetary hubs (see System Stars for more on these).
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.
