Comparison Merida Big Nine 40-MD 2017 vs Merida Big Nine 20-MD 2017

The model of the hub used in the front wheel of a bicycle.

The hub is the central part in the wheel through which the axis of rotation passes. Features of the behavior of a bicycle depend on its characteristics, in particular, “rolling” (the ability to move by inertia, without pedaling). Knowing the model of the front hub, you can clarify its characteristics according to the manufacturer's documentation, find reviews from other users, etc., in order to determine how this model suits you.

Model of the hub used in the rear wheel of a bicycle. See Front Hub Model for details.

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.

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).

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.

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".

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".

Features of the handlebar stem (see " Stem Adjustment ") installed on the bike. Here, both the offset model and its individual characteristics, most often the length and diameter, can be indicated. The stem itself can be either a separate part or an integral part of the steering wheel itself (the so-called integrated stem); the latter option is convenient in that the steering wheel cannot be skewed (unless broken), respectively, there is no need for centering.

As for the parameters, the rider’s landing depends on the length — the longer the takeaway, the more you will have to lean forward (ceteris paribus); strength and resistance to loads are directly related to the diameter; See “Cassette Model” for details on why the model name may be needed. It is worth noting that these parameters are important primarily for keen enthusiasts who pay attention to the smallest details in the characteristics of the machine; for most users, even advanced ones, such trifles are unlikely to be useful.

The model of the saddle supplied as standard with the bike. For more information on why you need to know the model of a particular bicycle component, see p. "Cassette Model".