The Short Answer is:
BMX bikes have small wheels because they are lightweight and have less friction, making them easier to maneuver for stunts and tricks. They also have a resistant frame to support jumps and are designed with a short rider in mind, allowing them to access the handlebar and saddle with ease.
BMX bike wheels come in multiple sizes, ranging from 12” inch to 24” inch.
The 20-inch (50.8 cm) wheel is the most common and is considered the true size for BMX bikes, while 24-inch (61 cm) wheels are designed for larger riders looking for similar geometry and maneuverability as the 20-inch size.
26″ wheels have a long history in the bike industry, starting as the standard for American made cruisers almost 100 years ago.
They’re chosen by BMX riders for their maneuverability, making flatland and aerial tricks easier.
When considering a new bike, it’s important to consider your top tube measurement which should be between 20.4”-21” top tubes.
Table of Contents
Why Do BMX Bikes Have Small Wheels? (The History)
BMX bikes have small wheels because they were designed with smaller cranks, sprockets, and seats to make them lighter and easier to maneuver.
BMX bikes first entered the market in the 1970s and traditionally have 20″ wheels.
Smaller wheels create a lower force of inertia, allowing riders to speed up quickly.
The Benefits of Small Wheels on BMX Bikes
BMX bikes have small wheels for a variety of reasons, including their lower moment of inertia which allows them to get up to speed quicker and climb better, as well as their lighter weight and ability to perform complex tricks.
Smaller wheels may offer a harsher ride and be challenged when it comes to rolling over rugged terrain, but they are beneficial for smaller riders due to their size.
Small Wheels and BMX Bike Performance: Speed, Control, and Maneuverability
BMX bikes are designed to be small and lightweight, making them easier to maneuver and control.
This is due to their smaller wheels, which reduce the weight of the bike and create a lower moment of inertia, as well as their narrower handlebars and shorter crank arms.
Additionally, BMX bikes feature wider tires for increased stability and grip on slippery surfaces, while freestyle models have a chainring (25 teeth) and sprocket (9 teeth) combination that requires less effort to accelerate quickly into a trick or jump.
The size of BMX bikes also allows riders to perform tricks and jumps without being interrupted by the seat, while advanced/progressive riders can customize their bikes with components such as steel frames, aluminum parts, and wide tires for improved performance.
BMX Bike Wheel Sizes: Understanding the Different Options
BMX bike wheel sizes vary depending on the type of bike and rider’s height. The most popular size for adults is 20 inches, which accounts for around 97% of sales, while 24 inch wheels are more suitable for street riding due to their balance between stability and agility.
For kids, 14 inch wheels can range from 355 to 400mm in BSD measurement, while 18 inch wheels have a BSD measurement of between 609 and 630mm.
27 inch bike wheels have a BSD measurement of between 609 and 630mm, while 29 inch bike wheels have a BSD measurement of between 710 and 820mm.
32 inch bike wheels have a BSD measurement of between 830 and 890mm.
Choosing the Right BMX Bike Wheel Size for Your Riding Style
Choosing the right BMX bike wheel size for your riding style depends on your reach and height.
Most BMX bikes come in one frame size, but there are some variations in length.
A handy chart can help you decide which size is best for you based on your height/age.
The most popular BMX bikes have 20 inch wheels, accounting for around 97% of all bikes.
When choosing a BMX bike, riders should consider factors such as weight capacity, frame geometry, tire width, handlebar length, pedaling style (e.g. flatland or jump), and gear ratio.
Components of BMX Bike Wheels: Rims, Tires, and Hubs
BMX bike wheels are composed of three main components: rims, tires and hubs.
Rims are typically made of alloy or carbon fiber, while spokes connect the hub to the rim and transmit power generated by pedaling.
Nipples play an integral role in keeping rims round and true.
Tires come in various sizes and tread patterns, with some offering better grip than others for different riding conditions such as dirt jumps or street riding.
Hubs can be either freehub (an extension of the right-hand side of a bicycle’s rear wheel hub) or sealed bearing (which is what most modern bikes use).
Maintaining Your BMX Bike Wheels: Tips and Tricks
Maintaining your BMX bike wheels requires regular maintenance and care.
This includes keeping bolts tight, cleaning and greasing the bike, tightening spokes/truing wheels, checking brakes and chain for wear and tear, and using a spoke spanner to straighten bent rims.
It is also important to check that pegs attached to wheel hubs are not loose before every ride, as well as pedals and crank for grip.
Additionally, it is recommended to use spray lubricant on braking surfaces instead of grease or oil.
Upgrading Your BMX Bike Wheels: When and How to Do It
Upgrading your BMX bike wheels is an important upgrade for safety and performance.
Double wall rims are the best option, as they can handle more abuse than single wall rims.
The cheapest way to upgrade your wheels is to buy a complete wheelset, but building a custom wheel is also an option. It’s possible to get exactly what you want by building your own wheel.
Other affordable upgrades include grips, tires, bars/forks, brake cables, stems, pedals and hub guards.
Frequently Asked Questions about BMX Bike Wheels and Their Size
How do small wheels help BMX bikes perform better?
Small wheels on BMX bikes help to reduce the weight of the bike, making it more portable and easier to maneuver obstacles.
Smaller wheels also provide increased tire compliance with the road surface due to higher pressure, as well as improved steering responsiveness.
Additionally, small wheels were initially designed for kids, making them ideal for short riders.
However, larger wheels can go faster than smaller ones because they have a larger radius and are more stable at higher speeds.
Are small wheels on BMX bikes less safe than larger wheels?
Small wheels on BMX bikes are generally lighter and easier to accelerate than larger wheels, but they may not be as stable at higher speeds.
Additionally, larger wheels require less effort to pedal than smaller ones. Therefore, it is difficult to definitively say whether small or large wheels are safer for BMX bikes.
Can I use a larger wheel size on my BMX bike?
Generally, you cannot use a larger wheel size on a BMX bike as it will hit the frame. The most common wheel size for BMX bikes is 20 inches, and the best tire width for racing BMX bikes is 1.75 inches wide.
However, you can change the tire width to a degree and as long as the first number of the tire size is 20 (or 2), it should fit just fine.
There are also wider ranges of wheel sizes available for taller riders and individual riding preferences.
What is the difference between 20″ and 24″ BMX bike wheels?
The main difference between 20″ and 24″ BMX bike wheels is their circumference. A 24″ wheel has a circumference of approximately 1911mm, while a 20″ wheel has a circumference of roughly 1594mm.
Additionally, the 24″ wheel will have a lower bottom bracket than the 20″ frame when compared to the wheel-axle height, and it will roll faster and absorb bumps better than the 20″ wheel.
The 24″ BMX bike is also known as a ‘cruiser’ BMX and is designed for larger riders looking for similar geometry and maneuverability as the 20-inch size.
What is the best BMX bike wheel size for tricks and stunts?
The most popular BMX bike wheel size for tricks and stunts is 20 inches, as it is the most versatile size for performing a variety of tricks.
However, dirt jump bikes can come with 20-inch, 24-inch or even 26-inch wheels depending on the size of the rider.
12” – 18” wheels are also suitable for BMX stunts and tricks, but 24” cruisers are better suited for cruising rather than performing tricks.
In conclusion, BMX bikes have small wheels because they are designed to be lightweight and easy to maneuver, which is essential for BMX riders who need a nimble and agile bike. Smaller wheels also promote faster speed by reducing the weight of the bike, making them portable and easier to handle obstacles.
Additionally, BMX bikes have smaller sprockets for faster acceleration and increased frame-to-ground clearance. While these features were initially meant for kids, they have become popular among adults as well due to their versatility and performance capabilities.