The wheels are robust, suitable for a wide range of terrains, and designed to fit wide tyres. Ideal if you like to ride on tarmac as well as on forest paths. The 28" wheel size is suitable for longer trips.
Front shock-absorbing fork - for comfort, better grip on different terrains, to get around obstacles, and for safer downhill descents.
The chainring is partly hidden under the chain guard, or scratch guard is added on the frame to protect it from scratches. Usually left fairly open for easy access when changing.
Saddle narrower, harder (compared to city bikes) for a sportier seat.
Both dynamos for comfort and separate battery lights to maintain a lighter design.
Tyres are available in a variety of widths and patterns, to suit the journey ahead. Often the lightness and durability of the tyre are taken into account. Thicker tyres enable a wider range of surfaces to be driven on.
Material - aluminium, the most common. Lighter than steel and stronger than carbon fibre. Used in many types of bicycles. Has the best price/weight ratio.