Nine-year-olds are at an in-between age where they aren’t small children anymore, but they’re not quite tweens either.
Finding fun outdoor activities and equipment for children this age can be challenging, but fortunately, most kids love riding, and bike sizing is easy.
You only need a couple of basic measurements. What is the best size BMX for a 9 year old?
The best size BMX for a 9 year old is junior or expert, depending on their height. A small to typical 9 year old will typically fit in the 4’3″ to 4’7″ height range with a 22 to 26-inch inseam. Meanwhile, a taller 9 year old will fall in the 4’6″ to 5’5″ range with a 24″ or larger inseam.
To see all of my up-to-date recommendations for bikes and cycling gear, check out this resource that I made for you!
Table of Contents
Best Size BMX For 9-Year-Old
The best size BMX for a 9 year old isn’t measured by age. You will need their height and inseam measurements to determine the frame and wheel size and the handlebar rise.
Height is a simple measurement, but many people don’t know how to measure an inseam for a bicycle.
When you measure for pants, the inseam needs to leave a little room, but it’s different for the seated height on a bike.
You need the length of the rider from the ground to their crotch but compressed as it would be when sitting on a bicycle.
Too short and the bike will be small, and too long means they won’t be able to tiptoe the ground and safely stop.
You can use the inseam to determine the lowest setting for your 9 year old’s bike seat.
It’s okay if it can rise higher because that will give them a little room to grow, but you don’t want it to drop below their inseam height. There’s no fix for a too-small bicycle.
BMX Bike Sizing Chart For Kids
Picking the correct size means having the proper measurements, but the numbers won’t have any meaning if you don’t know what to do with them. Fortunately, you can pick out a bike size easily.
Below I’ve compiled a quick height and age-based chart for finding the approximate bike size for your nine-year-old.
Kids BMX Bike Sizes By Height, Age & Frame Style
|Height Of Child||Age Range||Bike Frame Size|
|Under 4′||6 & Under||Mini or Micro Mini|
|4′ – 4’4″||5 – 7||Mini|
|4’3″ – 4’7″||7 – 9||Junior|
|4’6″ – 5’5″||9 – 11||Expert|
|5’3 – 5’7″||10 – 13||Expert XL|
|5’6″ and Up||12 – 17||Pro|
How To Choose BMX Size For 9 Year Old
Before settling on a size, make sure you check every aspect of the bike for a good fit. You can adjust some parts like the seat, but others, such as the frame, are not easily adaptable.
Below are the 9 things you should consider when choosing a BMX size for a 9 year old:
1 – Check The Inseam For The Seatpost
Inseam length is vital for any bicycle. Whether it’s a 9 year old’s BMX or an adult road bike, you need that measurement to find the right seat height.
An oversized bike will be unstable when it stops, and a too-small frame can cause the rider to bang their knees against the handlebars.
2 – Measure Their Height For Handlebar Rise
For most people, height correlates to their arm’s length. Meanwhile, the length of the rider’s arms determines the right handlebar rise for proper control.
As BMX Union explains, “We typically see taller riders using higher rise bars to help keep them from hunching over, making for a more comfortable ride. But, we also see a lot of smaller riders riding big bars because they are also comfortable, and some feel it can help increase leverage when it comes to bunnyhopping.”
3 – Go By Wheel Size
The average nine-year-old needs a sixteen to twenty-four-inch wheel on their BMX. Smaller children from 3’7″ to 4’3″ tall need sixteen or eighteen on their bikes.
Meanwhile, taller 9 year olds from four feet tall and larger need at least a twenty-inch wheel.
Remember that BMX bikes and wheels are traditionally small compared to other bike styles, and they’re meant to be ridden standing up rather than seated.
4 – Don’t Forget The Style
There are two general types of BMX. Racing bikes have lighter frames, while the heavier frames are typically freestyle bikes. Before you decide what BMX to get a 9 year old, I recommend checking out this video.
5 – Look At Reviews & Ratings
Sometimes checking the reviews and ratings can help you determine if a particular brand and size are suitable for your nine-year-old.
There are always variations because of the overall design differences from different manufacturers.
Not every BMX has reviews, but a few well-written ones can make a world of difference in finding the best size.
6 – Durability Is Key
Ensure that the frame is durable enough for the kid in question regardless of the size.
A smaller or lighter frame has advantages, but if your nine-year-old likes to play hard, then consider a beefier frame. You can go up a size for most height categories.
7 – Brake Type
Not all BMX have brakes. For 9 year olds, you might find pedal brakes on some of the micros and minis.
However, you’ll see zero, one, and two pedal options on the larger bikes. I strongly recommend brakes for 9 year olds, but taller kids can easily find BMX without them included.
8 – Frame TopTube Length
The length of the toptube is what determines the size of the frame. If your 9 year old needs a Micro or Mini, the top tube will be eighteen inches or less.
Top tubes up to eighteen and a half inches is a Junior while a nineteen to nineteen and a half is Expert and nineteen and a half to twenty is an Expert XL.
9 – Are They Between Sizes
BMX and other bike frames are made to accommodate various sizes, and they all overlap. This is not a mistake.
If your 9 year old Is strong and used to riding, then sizing up is your best bet. Alternately, for newer riders, or those who tend to be smaller, you should go with the small end for their height.
Helpful Tips To Know About What Size BMX For 9 Year Old
Although age can give you a general idea of what size BMX a kid needs, their height makes the real difference.
Don’t let a child’s age lead you to the wrong bike. Instead, always check that the proportions fit.
Here are more helpful tips to know about what size BMX for a 9 year old.
- When in doubt, buy a BMX online from a company with good customer service and multiple sizes of each frame and style. That way, if you need a larger or smaller bike, you can make an exchange.
- BMX bike wheels are generally one size smaller than traditional bikes for the kid’s size or age group.
- If you see a bike size listed in inches, it is the wheel size, not the actual bike.
Getting a BMX that is the right size for your 9 year old can help them ride more safely. Kids love biking, but a proper fit helps them keep control.
Since BMX is generally meant for racing or doing tricks, a good fit is doubly essential. Fortunately, all you need to find the correct BMX size is height and inseam.
Thanks to overlapping bicycle sizes, you can usually go up or down by one frame size based on the skill and comfort level of the rider.