Comparison Discovery Tron AM2 DD 26 2022 vs Discovery Trek AM DD 29 2022 frame 19

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 user's height recommended by the manufacturer is calculated according to several parameters. One is the wheel diameter, and the second and more important is the frame size. If everything is simple with the wheel size — it is round and always the same, then the frame size complicates the choice. Different types of bicycles have their own frame shape, so even the same size can be suitable for different heights. And this is not to mention the features of the manufacturer, who like to do everything for themselves, and not in a general manner. Therefore, the size of the frame of each bicycle has its own size and it is still better to choose a bicycle by personally “saddling” it. If this is not possible, then our point will tell you what height, according to the manufacturer, this configuration (frame + wheel) of the bike is designed for.

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").

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.

Additional equipment supplied with the bike.

— Wings. Protective devices in the form of shields that are installed over the wheels and protect the cyclist and others from water and dirt flying from the wheels while riding. Usually, they are made removable — in case you need to minimize the weight of the car.

— Saddle with springs. A saddle equipped with springs that make it softer and provide cushioning. Note that soft spring-loaded saddles are designed mainly for a calm, leisurely ride — for high-speed bikes (including advanced road bikers), narrow hard saddles are considered more suitable.

— Shield on the chain. Protective shield covering the bicycle chain. Note that the dimensions and design of such a shield can be different: in some models it covers the entire upper section of the chain from the front to the rear sprocket, in others it protects only the front sprocket itself from the outside. Anyway, the main task of such a device is to protect the chain from foreign objects, primarily the edges of the cyclist's clothing. The shield can be made removable — in case you need to reduce weight.

— Footboard. A device in the form of a small folding pin that provides additional support. With a footrest, the bike does not need to be leaned on a pole, wall, fence, etc. — it can be placed vertically on an...y relatively flat surface. Note that many bikes without a kickstand allow you to buy and install it separately.

— Peggy. Special devices installed on the axles of "stunt" bikes — BMX or mountain bikes of the corresponding specialization (see "Application"). Pegs look like extensions of axes pointing in both directions. The standard size of one such "continuation" is 11 cm in length and 4 cm in diameter. They are used for a variety of acrobatic routines, ranging from riding on pegs to sliding on edges, railings, etc.

— Boot. A classic bike rack is a platform for carrying various cargoes, mounted above the rear wheel. It is found mainly in city bikes (see "Application"), as well as some relatively simple mountain and road models. Separately, we note that it is at least highly discouraged to carry passengers on the boot, and in many countries it is expressly prohibited by traffic rules.

— Front boot. Boot (see above), located above the front wheel. The advantage of this arrangement is that the transported luggage is constantly in front of the cyclist's eyes. On the other hand, the front rack is usually attached to the steering wheel and turns with it; thus, the additional load can significantly complicate management. Therefore, this feature is relatively rare, usually as an addition to the traditional (rear) boot; the exception is tourism models (see "Application").

— Basket on the steering wheel. A basket for transporting various goods, installed in front of the steering wheel, above the front wheel; a kind of analogue of the front boot described above. At the same time, on the one hand, the basket is more massive, on the other hand, it is better suited for transporting large items or numerous small items. In addition, the cargo on the boot needs to be additionally secured, while this is not always required for the basket.

— Signal / call. A bell or other sound signal — for example, a horn — usually mounted on the steering wheel, at the cyclist's hand. This equipment is very useful for warning other road users of an approaching bicycle. And in some countries, the presence of a sound signal is mandatory according to traffic rules.

— Lighting equipment. In this case, the presence of a headlight, a taillight, and in some cases, both at once, may be implied; specific configuration should be specified separately. Anyway, such equipment is indispensable for riding at night: it makes the cyclist visible to other road users, and the headlight also illuminates the road. In many countries, traffic rules expressly prohibit driving at night without lights.

— Bottle holder. Dedicated water bottle holder, usually mounted on the frame. It is more convenient to carry a supply of water with you on such a mount than to keep a bottle in a backpack, bag, on the boot, etc. Some bike models with this function are immediately equipped with a bottle, for others it needs to be purchased separately.

— Pump. The presence of the pump in the delivery set eliminates the need to buy it separately; in addition, the “native” pump initially fits the existing mounts, while problems may arise with a third-party one. Note that most often the kit comes with relatively simple and compact hand pumps; they are not designed for large volumes of work, but they can quite cope with everyday tasks like pumping a flat tyre.