Max weight
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".
Wheel size
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
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.
Alloy wheels
Light-alloy wheels of a monolithic design, cast in special moulds from aluminium, less often from titanium. Bicycles with
alloy wheels are characterized by increased resistance to oncoming air flows, strength and durability, and aesthetic appeal. At the same time, alloy wheels are less resistant to side gusts of wind, have poor maintainability and are very expensive. Alloy wheels are found mainly on board city and road electric bicycles, also specialized racing bike models are equipped with alloy wheels.
Front rotor
Front rotor.
The front disc brake rotor is a perforated metal plate attached to the wheel hub. The reduction in speed of the bike occurs as a result of the compression of the brake disc by the pads, which are driven by cable tension (in mechanical type systems) or by means of a hydraulic circuit (in hydraulic disc brakes). The diameter of the front rotor can vary from 140mm to 220mm. The higher the number, the more efficient the brake is.
Rear rotor
Rear rotor.
An element of a disc brake system mounted on the hub of the rear wheel of a bicycle. It is to him that the pads are pressed when the brake lever is pressed. The use of a rotor ensures high braking efficiency. And it is higher, the larger the diameter of the rear rotor. Disc rotors are available in sizes 140, 160, 180, 185, 203 and 220 mm.
Speeds
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.
Freewheel cogs
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).
Rear derailleur
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".