Continuing with bike adaptations to specific problems people have, suppose you live in a hilly city and you want to climb a street up. One can use a electric bicycle (or e-bike) to ease pedaling. This type of bike is even more important for those who have heart problems and/or senior citizens. But what exactly is a e-bike?

An electric bike is a bicycle with an integrated electric motor which can be used for propulsion purpose. Although there are a variety of e-bikes, all of them allow pedaling without using the electric motor. Its starting in the late of the 19^th century was rather discrete, but its popularity has been growing in recent years and is used in private and public bike sharing systems, i.e. in bike tourist tours.

E-bikes are classified as:

• With pedal-assist: the electric motor is regulated by pedaling. Hence, the effort of the biker is increased in this electric bike with pedal-assist (or pedelec). This effect is counteracted in smooth streets in which one pay extra effort to save it in hill streets. This bikes have a sensor to detect the pedaling speed, the pedaling force or both.
• With power-on-demand: the motor is activated by a throttle in the handlebar. Sometimes this e-bikes have more power than the ones with pedal-assist. In turn, this kind of system presents three possible uses:
  • Riding with pedal power alone (only human effort)
  • Riding by only the electric motor
  • Combining both together at the same time

Tricycles can also have an electric motor.

Since the bicycle ancestors were created, bikes have evolved to make people life easier and funnier. Its adaptation capacity to the a priori problems most people have faced for ages has converted it into an extremely adaptable machine. Today I will talk about the tricycle.

A tricycle is a bicycle with three wheels. It has evolved in parallel with bicycles. It seems two French inventors developed a three-wheels vehicle powered by pedals and named it a tricycle back in 1789.

The third wheel is usually put in parallel to the rear wheel, although it also appears next to the front wheel in some tricycles . Why was it made up? To overcome the mobility problem some disabled people have had. Thanks to the extra wheel, one does not need to walk perfectly or have an absent vertigo. This fact makes even broader the importance of bike as a vehicle for everybody, the democratization of bikes. Moreover, the increment in stability in comparison to bicycles is favored by children and senior citizens. Furthermore, a tricycle is useful to carry weighted goods. The third point allows to better distribute the weight so that heavier merchandise can be carried. In addition, if a basket is incorporated to the bike, its power is multiplied.

On the other hand, tricycles are divided between cycle rickshaws (for passenger transport) and freight tricycles (for goods issues). Riders should pay special attention when cornering to avoid tipping the tricycle over as its lateral stability is not as good as it can look like.