Comparison Kellys Spider 30 29 2018 frame 19.5 vs Kellys Viper 30 26 2018 frame 15.5

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 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.

Possibility to disable the shock-absorbing system of the front fork (if available, see "Suspension"). Although shock absorption dampens shock, providing ride comfort, it also has a rather serious drawback — it reduces the efficiency of transferring energy from the pedals to the wheel. By disabling damping, you can significantly increase efficiency in conditions where vibration dampening is less important than good pedaling efficiency — for example, when driving on a flat road, or when driving uphill.

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.

Model of a cassette — a system of rear wheel gears — mounted on a bicycle. Cassettes of different models differ in characteristics and can belong to different classes — from entry-level to professional. Knowing the cassette model, you can get acquainted with its features in more detail (according to official documentation, reviews, user reviews, etc.). This is especially important when choosing a bike for professional cycling.

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".

The model of the shifters (see “Shifter type”) that are fitted to the bike as standard. For more information on why you need to know the model of a particular bicycle component, see paragraph "Cassette Model".

Features of the handlebar stem (see " Stem Adjustment ") installed on the bike. Here, both the offset model and its individual characteristics, most often the length and diameter, can be indicated. The stem itself can be either a separate part or an integral part of the steering wheel itself (the so-called integrated stem); the latter option is convenient in that the steering wheel cannot be skewed (unless broken), respectively, there is no need for centering.

As for the parameters, the rider’s landing depends on the length — the longer the takeaway, the more you will have to lean forward (ceteris paribus); strength and resistance to loads are directly related to the diameter; See “Cassette Model” for details on why the model name may be needed. It is worth noting that these parameters are important primarily for keen enthusiasts who pay attention to the smallest details in the characteristics of the machine; for most users, even advanced ones, such trifles are unlikely to be useful.