Generally bikes are built on the range of human sizes and have only the ability to adjust the distance between the saddle and the crank shaft and - limited, between saddle and handlebars. With increasing age, the human body size changes, making it inappropriate to use one bike whole or only part of the growth cycle kid - young - teen. On the market there are some limited solutions adjusting the size of a human and they bike on size refers to the use of small wheels with diameters between 12 to 20'' variation saddle position (long rods) and the use of long handlebars, tilt. In childhood growth is very rapid, which lead to a short-term use of a bike and buying a new bike with larger, age-appropriate, as costs.

A bike with adjustable size, adaptable to standard dimensions kid – young or young - teenager would solve the  problem. Concept ‘’Bike grow with me'' could be a factor in reducing the costs of families with children and to stimulate creativity in getting the original vehicle parts kits. Adjustable size bikes are built in two classes (K - kid - young, Y - young - teenagers), with an adjustable frame in five variants, with 4 mounting positions or front and rear wheels - specific size ranges K - 12, 14, 16, 20'', Y - 20, 22, 24, 26''. The framework will be built of aluminum alloy to obtain a weight as low. The consumer goods industry needs new innovative products to meet the growing demands of consumers.

The global bicycle market to grow to USD 44.40 billion during the period 2018-2022. The latest trend gaining momentum in the market is technological advances in bicycles industry. There has been an immense evolution in the bicycle industry. The key competitors are launching innovative bicycles and accessories, which will lead to significant market growth. Fork has four adjustment possibilities and saddle and crank shaft can be adjusted according to the standard dimensions of the user at a time.

The adjustment is made by varying the elements of the slide or change position of front forks in the 4 positions determined, changing the saddle position and crank shaft and by changing the front and rear wheels with more appropriate in ranges K – 12 - 14 - 16 - 20'', Y - 20 – 22 - 24 - 26'' and fixation by screws or clips.

Transmission chain is normally provided with tensioning mechanism so that it can ensure the dimensional variation. The wheels can be combined in many arrangements, which will result in obtaining the original concept bike, with wheels of different sizes.

This bike maintains 90% components of a classical bike and could be easily launch into production with minor modifications. The production cost is comparable with products already in the marketplace, because of small number of piece rechargeable and classical technology utilized.