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It can be a confusing process understanding which size bike will best suit you're child when surrounded with many different options, to help with this we've created a basic sizing guide to help get you started on choosing the perfect size BMX bike for your little shredder! Back when I first started riding BMX back in the early 1980's children's bikes were limited to 12" and 16" sizes before making the leap to a full size 20" BMX. Fast forward a few decades to 2023 and we are spoilt for choice with 12" balance/BMX bikes (Balance Bikes are a great option for those just starting out on two wheels, allowing riders to learn the basic fundamentals of balance and coordination before introducing pedaling), 14" BMX bikes, 16" BMX bikes and 18" BMX bikes, the introduction of balance bikes along with 14" and 18" bikes helps bridge the gap between sizes allowing young riders to feel more comfortable and confident on their bike.

Sizing is one of, if not the most important choice when it comes to selecting a new bike. Choose a bike that is too small and the rider will feel cramped whilst finding it difficult to pedal and maneuvere. On the flip side, a bike that is too big will be again be uncomfortable for the rider with difficulty reaching the handlebars and/or putting their feet on the ground along with causing issues with handling and maneuverability (all serious safety concerns). On the correct size bike a rider should be able to hop on and off without difficulty, feel comfortable and be easily able to reach the handlebars and put their feet flat on the ground. When it comes time to ride, a correct fitting bike should feel both responsive and maneuverable whilst being able to be easily thrown around for those brave enough to hit up the local jumps or skatepark. Keep in mind that BMX bikes are designed to ridden standing up. Most children's BMX bikes will feature a lower standover height than a regular children's bike to allow room for the rider to move around on the bike whilst jumping and turning etc. A regular children's bike will have a higher standover than a BMX bike to allow the rider to be seated whilst pedaling and maintain a smooth pedaling motion.

Wheel Size Height From Height To
12" Balance 65cm 85cm
12" 70cm 95cm
14" 90cm 115cm
16" 95cm 120cm
18" 120cm 145cm
  • 12"-14" BMX Bikes

    The youngest of riders will start their BMX journey with either a 12" or 14" BMX Bike or Balance Bike. 12" BMX Bikes are ideal for riders approximately 2 to 4 years of age while 14" BMX Bikes are the ideal next step for those who have outgrown a 12" but aren't quite ready to step up to a 16". 

  • 16" BMX Bikes

    Once they've mastered the basics on a 12 or 14" it's time to make the step up to a 16" BMX Bike! Young riders 5-7 years of age will find a 16" BMX to be more responsive & manoeuvrable than a regular children's bike, which in turn makes for easier riding, more confidence & good times!

  • 18" BMX Bikes

    18" BMX Bikes are the ideal size for when a rider has outgrown a 16" BMX but aren't quite tall enough to make the step up to a 20". Riders approx 7-10 years old will find an 18" BMX Bike to be lighter and more manouverable than a 20" BMX, which in turn makes for easier riding and more fun!

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20" BMX bikes have long been considered the "standard" BMX size. Sizing for 20" bikes is based off of the length of the frames top tube (measured from the centre of the seat tube to the centre of the head tube) and for complete bikes can vary from 18.5" to suit young riders moving up from an 18" wheel BMX, to 21.25" for riders 180cm + in height, with aftermarket frames available in lengths of up to 22". With these variances in top tube length also come changes in frame geometry such as chainstay length, standover height, bottom bracket height along with head tube and seat tube angles, these all play an important role in rider comfort along with the intended style of riding the bike is designed for. While there are a variety of top tube lengths available for different brands, please see below for a breakdown of the most common top tube lengths for 20" BMX bikes along with their corresponding suggested rider heights.

  • 18.5" - 19.5" Top Tube

    Idealy suited to riders approximately 140cm to 155cm in height. Popular bikes in this size range include the Blackeye Recruit (18.5"TT) and the Division Reark (19.5"TT).

  • 19.5" - 20.25" Top Tube

    Idealy suited to riders approximately 150cm - 165cm in height. Popular bikes in this size range include the Cult Access (20"TT) and the Wethepeople Nova (20"TT).

  • 20.25" - 20.75" Top Tube

    Idealy suited to riders approximately 160cm - 175cm in height. Popular bikes in this size range include the Radio Evol (20.3"TT) and the Cult Control (20.75"TT).

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  • 20.75" - 21" Top Tube

    Idealy suited to riders approximately 170cm to 180cm in height. Popular bikes in this size range include the Colony Premise (20.8"TT) and the Sunday Broc Raiford Forecaster (21"TT).

  • 21.25" + Top Tube

    Idealy suited to riders approximately 180cm or taller. Most complete bikes will max out at a 21" top tube with aftermarket frames a popular choice for riders who require 21.25" + frame.

  • 22" - 29" BMX Bikes

    BMX bikes are also available in 22", 24", 26" and 29" wheel sizes with 24" to 29" bikes often referred to as BMX cruisers. These sizes are great options for those who do not feel comfortable on a 20" or are after a more relaxed ride for long distance/commuting.

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If you have any questions in regards to the information in this guide please feel free to visit us in store at 108 High Street Cranbourne, call us on 0359961049 or email [email protected].