It is very important to buy the right size of bike. The criteria for sizing a bike up for a child differs slightly from that used for an adult.
In the case of children, you want a bike that will last as long as possible by giving plenty of growing room, but at the same time, not impeding safety because the bike is too big to start with!
In the case of adults, growing room is not really a factor to consider anymore, (not in the height department anyway!) Having said that, getting a frame size that's too big for you will result in an uncomfortable and possibly even dangerous bike.
If the bike is for a child, they generally fall into age categories based on the average size of a child of a specific age. There is no hard and fast rule that says you must buy a bike of a particular size for a child of a specific age. If the child is comfortable and not too stretched on the bike, and they can manage all the controls, ie. turn the handlebars safely, reach the brake levers and operate them, AND touch the floor with their tip-toes, then there is nothing to prevent you from selecting a bike in a bigger age category.
12" Wheel Cycles: Suitable for ages 3 to 5
First bikes, or pavement bikes are 12" wheel for average ages 3 to 5. Larger children may benefit from a 14" wheel cycle.
Once a child has learnt to ride without stabilisers (generally about age 5) they will move up to a 16" wheel cycle. These generally do not come with stabilisers, but they can be added if required.
Once you get into the realms of 20" wheel bikes and above, you may be offered multiple frame sizes. The benefit of this is the ability to fit a younger child onto a bigger wheeled bike if they are confident riders. Whilst 20" wheel bikes come in a variety of frame sizes, generally a particular model will only come in one frame size.
Once you are into 26" wheel bicycles, then size is only determined by frame size. The size of the frame is measured from the centre of the chainset (the thing the pedal arms are attached to) to the top of the frame at the point where the seat post is inserted. As we are in good old blighty, these are still measured in inches! Unfortunately some manufacturers measure their models to the centre of the intersection of the top tube and the seat tube, which can throw some of the sizings out a little. If in doubt, please contact us and we should be able to tell you which way a particular bike is measured. v The following rules of thumb should be applied when you try a bike for size:- v Mountain bikes: Standing flat footed on the ground, you should have a minimum of 2" (5cm) clearance between yourself and the top tube of the frame.
Racers: Standing flat footed on the ground, you should have a minimum of 1" (2.5cm) clearance between yourself and the top tube of the frame.
A simple calculation can be used to estimate your required frame size if you are not able to sit astride a bike to measure.
1. Measure your inside leg measurement to the floor
This will give you the maximum frame size that you will need.
But buying a bike of the correct size is not just about the height from the ground. As bikes get bigger height-wise, they also get longer. The distance from the saddle to the handlebars increases, on average, by 1" (2.5cm) for every 2" (5cm) increment in frame size. So although you may be able to stand astride a bigger framed bike, you must also enure that you can still comfortably reach the handlebars and manage all the controls. Remember that the saddles on all bikes are adjustable by between 4" and 10" so any bike can be tailored to fit you perfectly.
The main thing to remember is that a bike which is too big, can be extremely dangerous.
And finally, let's settle the score on a couple of common myths...
1. Frame size on a bike with a given wheel size DOES NOT affect the price. Larger frames do not cost more, and smaller frames are not cheaper.
2. Gents triangular frames are NO stronger than ladies step-through frames. However, they ARE more rigid and do flex less.