How Do You Choose The Right Bicycle Size?

Depending on the purpose of a bicycle the size and make of a bike can be decided. For mountain biking, bikes of the size where a person can comfortably place their feet on the ground without having to stand on their toes are a must. Mountain biking requires frequent halts and stops where the rider has to balance himself by resting his feet on the ground. In racing bikes riders prefer bicycles that have large wheel circumference. The larger the wheel the easier they find it to achieve higher speeds easily. For children people prefer cycles which are of different height depending on age but for growing children cycles which are a few sizes bigger are recommended as this is rumoured to promote growth in height. Finally people wanting to perform tricks generally select BMX type bicycles that are small in size and easy to handle.

It all depends on the size of the person who the bike is for!
There's no point in getting a very big bike for a small person they wouldn't be able to sit on the seat or reach the pedals.
To be comfortable on a bike you need to be able to both sit down comfortably and reach the peddles comfortably.
Many bikes can be adjusted so go to a good stockist and try alot of bikes to see which one fits you best.