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Why Size Matters!

Size is the most important aspect to get right when deciding on a bike for your child. If the bike is too big or too small, it can ruin your child's first biking experience and lead to accidents. The kids bike sizing guide below will give you an overview of the various kids bike sizes, and show you how to choose the best size bike for your child.

What size do kids bikes come in?

Kids bikes come in these different wheel sizes: 12 inch, 14 inch, 16 inch, 18 inch, 20 inch, 24 inch, and now even 26 inch. The wheel size is based on the diameter of the tire (see below) and as each tire size gets larger, so does the size of the bicycle frame. These different wheel and frame sizes help companies design bicycles that will fit kids of all ages and heights. The most common sizes are: 12 inch, 16 inch, 20 inch, and 24 inch. As we will learn more later on in this post, wheel size is NOT the best way to choose a bicycle for your child.

Balance Bikes

12 inch bikes are typically equipped with pedals and training wheels, but over the last few years balance bikes, bikes without pedals, have started to gain more popularity. Instead of teaching kids to learn pedaling first and balance later, balance bikes take a different approach - teach kids balance first and pedaling later. This has been a gamechanger for teaching kids 1 - 4 years of age how to balance, and is the reason kids can now jump straight into their first pedal bike (14 inch +) without using training wheels.

Balance bike fit: When sitting on the bike, kids this age should be able to put both feet flat on the ground and their body should be in an upright walking position. They helps children learn balance and prevents tip over accidents.

Pedal Bikes

A child's first pedal bike is one of the most exciting gifts of independence and freedom a kid will receive. With the growing popularity of balance bikes, children are now able to ride a pedal bike without training wheels as early as 3 years old! This has spawned a completely different way for kids bike brands to think about childrens bike design. A child's first pedal bike should fit differently than their second pedal bike (and beyond).

First pedal bike

On a child's first pedal bike, their heel should only be up off the ground 1 - 2 inches max. Timid riders should stick closer to 1 inch while athletic riders can be closer to 2 inches. This will put your child into a more efficient pedaling position while allowing them to touch the ground after braking.

Second pedal bike

On a child's second pedal bike and beyond, they should be up on their tippy toes 2 - 3 inches. Timid riders should stick closer to 2 inches while athletic riders should be closer to 3 inches. Since children will be riding farther on their second pedal bike, they will want maximum leg extension for efficient pedaling.


Choosing the bike by wheel size (the old way)

If you have ever purchased a bike before, you have probably seen a chart like the one below. These charts are designed for you to use your child's height to determine the correct wheel size. Sounds simple right? Then you finally get into the store, sit your child on a few bikes with the correct wheel size, only to realize that the bikes seem to fit differently.

Why doesn't this method always work well?

The main problem is the size of the bike is not solely determined by the wheel size of the bike. The size of the frame and design of the geometry also matter. This is why the same company can have two 20 inches bikes that are designed to fit children of completely different heights. An example of this is illustrated below. Notice how both bikes have 20 inch wheels but the bike in figure 1 has a smaller wheelbase and lower seat position. This bike has been specifically designed for a smaller kid. There are more extreme examples if you begin to compare two bikes from different brands. Another issue with this method is trying to figure out which bike is going to last the longest and how long the bike is going to last.

Fig 1 - 20 inch small
Fig 2 - 20 inch large

Choosing the right size Guardian bike with RideSizer (the future way)

Our goal at Guardian Bikes is to deliver you the safest children's bikes directly to your door. A big part of this is helping you choose whether our 16 inch, 20 inch, or 24 inch, is the best fit for your child. That is why we have launched a new tool on our site called RideSizer - the world's first kids bike sizing tool that helps you choose the perfect bike for your child. Simply enter your child's height, and RideSizer will show you exactly how your child fits on the recommended bike while also letting you know how long the bike will comfortably last. The tool also shows you exactly how your child will grow into the bike and educates you along the way. The tool is completely free and takes just a few second to get started. Get it a try here!