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BMX Bike Buyer's Guide

BMX Size

When looking to purchase a BMX, the process can be daunting with a huge selection of brands, styles, and components to choose from. BMX bikes come in various sizes, so it's important to choose one that fits you correctly to ensure optimal performance and safety. This is especially for beginner BMX riders. You can use the sizing chart below to find the most suitable size, or better yet, visit us in-store for in person fitting advice.

For the youngest riders, wheel size is the main measurement to watch. Junior BMX bikes are available with 12”, 16” or 18” wheels. Refer to our chart below to find the most suitable wheel size.

Once a rider graduates to a bike with 20” wheels, there is a little more choice in frame sizing. Frame size is loosely based on rider height, but rider preference is also a big factor. Top tube lengths typically range from about 20” to 21”. A rider who prefers a more nimble bike, something best for spinning and technical tricks, should choose something closer to 20”. For a rider who prefers a more stable bike (something suited to big air and smooth, flowy tricks) the best options are closer to 21”.

There are also BMX bikes with wheels that are larger than 20”. These bikes are best suited for very tall people, or just riders who want a bike that is more comfortable for cruising around.

 Rider Height BMX Bike Size
Up to 92cm / 36” 12” wheel

92cm - 107cm /
36” - 42”

16” wheel
102cm - 132cm /
40” - 52"
18” wheel
121cm - 163cm /
48” - 64”
20” wheel, 18” - 20.25” TT
152cm - 183cm /
60” - 72”
20” wheel, 20.25” - 21” TT
178cm / 70” + 20” wheel/21” TT
or 22”/24” wheel

BMX Parts

Once you have figured out a suitable size, you may want to dive deeper and learn more about the different parts available on complete BMX bikes. With the wide variation in pricing, you can be sure there’s many levels of parts available. Below are a few key terms that should help:

Sealed Bearings vs. Unsealed Bearings

The wheels, cranks, and headset all have bearings which allow them to move smoothly. Unsealed bearings are more affordable, but often require more regular adjustment and maintenance. Sealed bearings use a cartridge style bearing that usually does not require adjustment.

For a beginner rider, unsealed bearings usually suffice, but if any play develops in the bearing (which is noticeable if the part develops a wobble, or starts making noise), then the bearing should be adjusted as soon as possible to avoid damage.

Sealed bearings are a more premium option. They are typically stronger, more durable, and simpler to service. You will find sealed bearings on intermediate to advanced level completes. If a bike’s specifications don’t say sealed, or unsealed, they are usually unsealed. Another term for unsealed is “looseball”.

Chromoly Steel vs. Hi-Tensile Steel

The frame, fork, bars, and cranks on a BMX bike are all constructed from steel, and there’s two main types: 4130 chromoly, and hi-tensile steel. The material found in these components mostly has an effect on the bike’s weight. Lighter bikes are considered preferable because they are easier to maneuver and flick around.

Chromoly steel is usually stronger than hi-tensile steel - however this does not automatically mean that chromoly parts are stronger than their hi-tensile counterparts. Due to its additional strength, engineers will use less material to achieve the same strength as a hi-tensile steel part, which lowers the weight. Most hi-tensile parts achieve the same strength as chromoly, but with a weight penalty.

With all of that said, it should be apparent that most entry level bikes use primarily hi-tensile steel, and as you move up, the amount of chromoly steel used throughout the bike increases. Intermediate bikes will usually have chromoly cranks, and the main tubes of the frame will be chromoly. Once you move up to expert level bikes, you will find full-chromoly construction.

If a bike’s specs don’t say whether a part is chromoly, or hi-tensile steel, it will usually be hi-tensile steel.

Single Wall vs. Double Wall Rims

A big consideration for your new bike is what type of wheels it has. Some wheels have single wall rims, and some have double wall rims. This refers to the cross-section of the rim. Single walls are found on entry and intermediate level bikes. They are the most affordable option. Double wall rims have an additional reinforcing wall which makes the wheel much stronger and stiffer.

For beginners, single walls are a good place to start. They’re a little bit lighter than double walls which helps with learning the basics. Once you start learning spin tricks, or hitting larger jumps, a double wall becomes beneficial as it will handle the abuse much better.

If a bike doesn’t list its rims as single wall, or double wall, it is usually safe to assume that they are single wall.

You can shop our range of complete BMX bikes here.

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