Comparison Ardis City Trekking 26 vs Ardis Tour D CTB 26

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.

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.

— Aluminium. In this case, aluminium is the simplest and most unpretentious option. Its advantages include light weight; on the other hand, in the absence of shock absorption, the steering wheel with such a fork is highly susceptible to vibrations, and in terms of durability, aluminium is somewhat inferior to steel.

— Steel. Another relatively simple option, which at the same time is considered more advanced than the aluminium described above, and is found even in fairly expensive pro-level bikes. This is due to the fact that steel is noticeably stronger and more durable, as it is not as susceptible to "metal fatigue". However such forks weigh a little more than aluminium ones.

— Chromium molybdenum steel. A type of steel that is more advanced than more traditional grades. Among the main advantages of such alloys are high strength and reliability; at the same time, due to such properties, individual elements of the forks can be made thinner, and the forks themselves can be made lighter than ordinary steel ones. The main disadvantage of Cro-Mo steel is the rather high cost.

— Carbon. Lightweight and high-strength carbon fibre forks effectively dampen small bumps in the road under the wheels of the bike and slightly spring on small potholes, thereby providing cushioning on bumpy roads. The carbon fork facilitates the design of the front of the bike. Most often it is found on board "highways" and "gravel roads", less often it is installed in o...ff-road fatbikes. Vulnerable point — carbon forks break under the influence of strong point impacts.

The presence in the design of the bicycle of a separate shock absorber under the saddle. The seatpost cushioning significantly reduces the vibration and shock felt by the rider, which is especially important when riding on uneven terrain.

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.

Varieties of rims are determined by the number of horizontal jumpers in the design.

— Single. The simplest type of rim, similar in cross section to the Latin letter U. It is used mainly in entry-level bicycles.

— Double. Such a rim differs from a single rim by the presence of an additional horizontal bridge. Figuratively speaking, it resembles the same letter U, but with a double bottom. The features of this design are such that it is able to provide increased strength even with less weight than a single one. On the other hand, double rims are more difficult to manufacture and therefore more expensive. They are used primarily in bicycles where high resistance to stress is required — in particular, mountain varieties (see "Intended use") for freeride and cross-country.

— Triple. A further development of the idea of a double rim is a design with two additional horizontal bridges. This provides even greater strength, however, the weight increases quite noticeably. In addition, initially the second jumper was provided to strengthen the side surface, in order to avoid damage during the operation of rim brakes (see "Front brake", "Rear brake"); however, today most powerful brakes are disc brakes, and this problem is losing its relevance. Because triple rims are quite rare.

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.

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.