Comparison Dorozhnik Amber 2019 vs Ardis Postman 28

The year to which the manufacturer classifies the bicycle (more precisely, the model range that includes this model).

The significance of this parameter is that the model range is updated every year, and two bicycles with the same name, but from different years, can differ significantly in characteristics and equipment. At the same time, new models ( 2024, 2023) usually cost more, and older ones ( 2022, 2021, etc.) are sold at reduced prices.

It is worth considering that a later year of manufacture in itself does not necessarily mean more advanced characteristics - manufacturers can change them in the direction of simplification. So the model of previous years may be in no way inferior to the new bike.

The maximum load allowed for a bicycle is, in other words, the maximum weight that it can normally carry in normal use. Of course, when calculating the load, the weight of both the cyclist himself and the additional load that he carries with him is taken into account.

The permissible load must definitely not be exceeded: even if the bike does not break down immediately, off-design loads can weaken the structure, and an accident can occur at any time. Also note that it is desirable to have a certain weight margin — at least 15 – 20 kg: this can be useful in case of transporting heavy loads and will give an additional guarantee in emergency situations (for example, when a wheel gets into a pit). Considering that the average weight of an adult is about 70 – 80 kg, bicycles with a permissible load of up to 100 kg can be classified as "lightweights", from 100 to 120 kg — to the middle category, more than 120 kg — to "heavy trucks".

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.

The presence or absence of a depreciation system on a bicycle, as well as the type of this system.

— Without depreciation (rigid). In such models, the wheels are fixed directly to the rigid elements of the frame; there are no depreciation devices. Due to this, the design of the bicycle is simple, the weight is small, the cyclist feels all the features of the road topography as much as possible, and the maximum efficiency of pedaling is also achieved, which is important, for example, for road models (see "Destination"). At the same time, structural rigidity is a "double-edged sword". On the one hand, "feeling for the road" is important for BMX and some mountain models (see "Purpose"); on the other hand, the lack of shock absorption significantly increases the load on both the structure and the rider himself, leads to increased wear, fatigue and some risk of injury on rough roads.

— Depreciation of the front fork (hard tail). The most popular type of cushioning in adult bikes (see "Age Group"), especially urban and mountain types (see "Purpose"). In accordance with the name, in such bicycles, the shock-absorbing device is installed only on the front fork, while the rear wheel is rigidly fixed. The presence of a shock absorber somewhat increases the weight of the structure and complicates its maintenance, however, the advantages of such a scheme significantl...y outweigh the disadvantages: hard-tails combine good handling, “road feel” and ride comfort, including and on rough terrain.

— Rear fork. Bicycles in which only the rear wheel is damped, while the front wheel is rigidly fixed. The rear shock absorber is designed to provide additional comfort when hitting various bumps, and the absence of a front shock absorber reduces the overall cost of the machine. This option is found mainly in urban models, including electric bicycles (see "Application"); in other varieties, the use of rear shock absorption is not practical.

— Two-suspension (full suspension). Bicycles equipped with shock absorbers on both wheels — a fork in front and a special suspension in the back. Such models are as comfortable as possible for driving on rough terrain, because. They dampen the vibrations felt by the cyclist best and provide the best grip on uneven tracks. At the same time, the presence of a rear shock absorber "eats" part of the energy coming from the pedals, and you have to spend more effort to ride. To avoid this, many two-suspension bikes can be provided with front and rear suspension lockouts (see below), but full suspension complicates the design anyway, increases its weight and price. Therefore, this type of cushioning is relatively rare, mainly in certain varieties of mountain bikes (in particular, for cross-country and freeride; see "Purpose").

Front fork suspension type (if available, see "Suspension"). All shock absorption systems in bicycles work in two directions: vibration damping (damping) and impact energy absorption (cushioning). Accordingly, they have two main components: a damper and a shock absorber. Depending on the design features of these elements, the following types of depreciation are distinguished:

— Spring-elastomer. In this case, the role of a shock absorber is played by an elastic spring, and the role of a damper is played by a rod made of an elastic, well-compressible material, the so-called elastomer. This type appeared as a development of conventional spring damping systems, it is more durable, but poorly suited for low temperatures — the elasticity of the elastomer in such conditions decreases, which negatively affects the characteristics of the system.

— Spring-oil. Systems using a spring as a shock absorber and an oil cartridge as a damper. This design is somewhat more resistant to low temperatures than spring-elastomer, and in general has quite good characteristics, due to which it is quite widely used in various types of bicycles. The main disadvantage is the higher (on average) cost.

— Air-oil. Combined systems consisting of an air cylinder that acts as a shock absorber and an oil cartridge that acts as a damper. They appeared as a development of “pur...e” air systems, which had a serious drawback: even with high-quality maintenance, the seals wore out rather quickly, which could disable the shock absorber. Air-oil systems are more durable and easier to maintain, while being quite efficient and weighing little. The latter is especially valuable for cross-country (see "Purpose"), where it is required to combine depreciation with a low weight of the machine.

Front fork travel on bicycles with damped suspension (see "Suspension"). Roughly speaking, the travel of a fork is the maximum distance that its size can be reduced by compression during shock absorption. The longer the fork travel, the better the shock absorption and “soft” ride it provides, but not all bikes require a lot of travel. Even within the same type (see “Purpose”), depending on the specific application and riding style, the optimal fork travel will be different — for example, freeride mountain bikes need good shock absorption, and for cross-country, on the contrary, a long fork travel will be redundant.

In general, if you do not plan on extreme cross-country riding or doing cycling tricks, this parameter is not critical. However, when choosing a bike for serious cycling, it is worth checking the recommended fork travel values (according to specialized literature or from professionals) and making sure that the desired model corresponds to them.

Tyre model supplied with the bike as standard. Different tyres have different purposes and characteristics; knowing the tyre model, you can clarify these points and check how they correspond to your wishes. This is especially important when choosing a machine for serious cycling.

A type of rear brake fitted to a bicycle. Here are the main types of brakes found today:

— Obodnoy. Rim brakes are those that work by pressing the brake pads against the rim of the wheel. They transfer the braking force from the handle to the pads via cable traction. The common advantages of all rim brakes include simplicity of design, light weight, low cost, good interchangeability of parts, as well as minimal load on the hub and spokes. On the other hand, such brakes wear out the pads and rim, require periodic adjustments, and lose effectiveness if the rim becomes dirty, icy, or bent.

Structurally, the differences between the subtypes of rim brakes lie in the way they are attached to the bicycle frame. Moreover, each variety has found its own area of application. Thus, V‒brake is common in teenage, recreational and budget mountain bikes, the pincer subtype is used in road and city bikes, and U-brake is practiced in BMX bicycles.

— Disk mechanical. A kind of mechanical brakes (see above), in which the pads are pressed against a special brake disc (rotor) rigidly fixed to the wheel hub during braking. Such brakes are much more efficient than rim brakes, they are not as sensitive to dirt and retain their full performance even with rim curvature. Among the disadvantages of disk systems, one can note greater weight and cost, increased load on the bushing and spokes, as well as dif...ficulty in repair.

— Disc hydraulic. Disc brakes (see above), in which the force on the pads is transmitted not by a cable, as in mechanical systems, but by means of a hydraulic circuit. They are the most advanced option in terms of performance: the use of a disc provides high braking efficiency, and the hydraulics give excellent modulation and allow you to accurately dose the force on the handle. At the same time, such systems are not cheap, and in addition to the general disadvantages of disc brakes, they add sensitivity to damage: a violation of the tightness of the circuit leads to fluid leakage and brake failure.

— Drum. Brakes in which the pads are pressed from the inside to a special drum; in this case, the role of this drum is usually played directly by the wheel hub. One of the advantages of such systems is that almost the entire mechanism is hidden inside the drum and protected from dust and dirt, making it virtually maintenance-free. In addition, drum brakes do not wear out the rim and can work even with a bent wheel. On the other hand, such systems are rather bulky and their effectiveness is lower than that of rim and disc brakes. In addition, the drum brake on the rear wheel can be used with either a single speed cassette or a planetary hub (see below) — these brakes are not compatible with classic multi-star cassette derailleurs.

— Roller. A variation of the drum brakes described above, in which the pressing of the pads to the drum is ensured by the so-called. roller mechanism. The drum in this case, usually, is performed separately from the sleeve. Due to this, it was possible to achieve higher efficiency (comparable to disc brakes) while maintaining the main advantages of the drum circuit — unpretentious maintenance, good protection against dirt and independence from rim curvature. However, roller brakes are not cheap, and besides, they have a number of their own drawbacks — in particular, they worsen the roll and make it possible to spin the wheel back when the brake is pressed. Yes, and with classic speed switches, such systems are poorly compatible.

— Pedal. In fact, it is a variation of the drum brake described above, controlled not by a handle, but by pedals: braking is carried out by pressing the pedals in the opposite direction. This method of control greatly simplifies the design, eliminating unnecessary handles and rods. At the same time, in some moments it is not very convenient and practical. So, the effectiveness of the brakes is directly dependent on the position of the pedals — for maximum efficiency, they must be horizontal at the time of braking, and in a vertical position, difficulties may arise. In addition, when the chain falls off, the cyclist, in fact, loses the brake. Thus, pedal mechanisms are used relatively rarely — mainly in city bikes that are not designed for particularly high-speed riding.

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.