Bicycle Kellys Vanity 70 27.5", Size 16.5" (42cm), Purple

The frame is made stronger than other types of bikes, and is designed for the best possible rideability. The geometry can be chosen for optimum stability or manoeuvrability.

Wheel sizes can be varied according to the purpose of the ride. 26" wheels are usually used for more challenging trail sections. These wheels are the strongest and most manoeuvrable, but have poorer rolling characteristics compared to discs. The 27.5" size is ideal for maintaining the ratio of manoeuvrability to stability. Many manufacturers use these wheels on low-frame bikes to maintain good rolling characteristics and a low centre of gravity. 29" wheels are used on most mountain bikes. They have good rolling characteristics and slightly improve shock absorption.

Front shock-absorbing fork - for comfort, better grip on different terrains, to avoid obstacles, and to descend downhill more safely.

Main tube is open for easier access for cleaning and replacement. This is important because the higher load of mud during uphill pedalling makes the chain of a mountain bike the quickest to wear out.

Rarely available with mudguards, but essential for clean clothing and comfortable riding in the worst weather conditions, and possibly available as an optional extra.

The saddle is narrow - for a firm and flexible enough seat for uphill pedalling.

Dynamos are rarely found in them to keep the construction light. Therefore, headlamps are chosen to be placed on the helmet to give greater visibility, especially on bends.