Comparison Discovery Rocket AM2 DD 24 2019 vs Ardis Jetix MTB 26

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 age group to which the bike belongs. This parameter in our catalogue is indicated only for teenage models; if the age group is not specified, it means that the car belongs to “adults” (children’s bikes are placed in a separate section of the catalogue).

Teenager bikes are designed for teens aged about 10-14 years old, for whom children's bikes are already small, but adults are still too big. Such bicycles are similar in design to adults and differ from them mainly in slightly reduced sizes — in particular, the diameter of the wheels (see below) in them usually does not exceed 24 "(there are exceptions, but extremely rarely).

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 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.

Type of rear suspension damping in full suspension bicycles (see "Suspension"). To date, there are such options:

• Spring-elastomer.
• Spring-oil.
• Air-oil.
• Air.

The first three options are described in detail above in the "Type of cushioning (fork)" section above. In air systems, as the name implies, the working element is air, which acts as both a damper and a shock absorber. This is very convenient due to the ability to change the stiffness of the suspension by adjusting the pressure in the system — the higher the pressure, the harder the damping. However, such shock absorbers are prone to rapid failure due to wear of the seals and require more careful maintenance than similar air-oil shock absorbers in many respects.

The nominal diameter of the bicycle wheels. Usually, this paragraph actually indicates the size of the bicycle tyres supplied in the kit, more precisely, the outer diameter of the tyres.

Wheel diameter is traditionally indicated in inches. For bicycles of different purposes and age groups (see paragraphs above), there are certain size standards. So, adult mountain models are equipped mainly with 26 " wheels, "road" and urban ones — with a slightly larger diameter (mostly 28 "), and BMX for the most part — much smaller; children's and teens' bikes have smaller wheels than similar adults' bikes.

Other things being equal, larger tyres hold speed better and work out small bumps on the road; and relatively small wheels are more “sticky”, they provide more torque and better traction. This is the reason for the above-described difference in wheel sizes between bicycles for different purposes. Such nuances will be useful if you choose a car from several models with similar characteristics, but different wheel diameters. Here it is worth considering the features of the planned application. For example, for urban and "road" driving — on a hard surface without any special irregularities and elevation changes — it is better to choose larger wheels, and for dirt roads with ups and downs — smaller ones.

Also note that tyres are replaceable, and many bikes allow the installation of tyres of...a “non-native” size — for example, 29 "on a model with 28-inch wheels. It is also worth considering that wheels (tyres) of the same size may differ in inner (landing) diameter These nuances are described in detail in special sources.

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.