7 Best Kids BMX Race Bikes (Micro Mini, Mini, Junior, Expert)

So you want to get your child a good BMX race bike. But what size do they need? What brands are good? What else do you need to consider?

This guide is here to help you figure all of that out. We’ll go over the sizes of BMX race bikes, which size your child needs, the best brands and their offerings, and other things you should think about when buying your child a new bike.

Kids BMX Bike Sizes Explained

If you’re new to BMX racing, the bike sizing can be very confusing at first. The naming convention is very different than most kids bikes which are sized by their wheels–i.e. 12 inch bike, 14 inch bike, etc.

There are four sizes of kids BMX racing bikes:

Micro Mini (under 5)
Mini (5-7)
Junior (7-9)
Expert (9-11)
Expert XL (10-13)

Teens can fit on a regular adult (Pro) BMX bike, so we won’t focus on those in this article. That said, if you’re looking for a BMX racing bike for your teen, you can still choose a bike from one of the brands we list below.

BMX Bike Size Chart

If you’re not sure which size BMX bike your child needs, this chart should help as a good starting point. Keep in mind that height is a better indicator than age. As we all know, kids grow at different times.

It’s also helpful if your child can try some of these sizes before buying, especially if they are right in between sizes. Many local tracks offer a rental or loaner program.

Size	Age	Height
Micro Mini	<5	3’6″-4’0″
Mini	5-7	4′-4’4″
Junior	7-9	4’3-4’7″
Expert	9-11	4’6″-5’5″
Expert XL	10-13	5’3-5’7″

Kids BMX Race Bike Brands

Listed below are our favorite brands for kids BMX race bikes and their line-ups. Whatever age or size of your child, you’ll find a bike for them.

DK

DK makes great BMX race bikes and they are (relatively) affordable which makes them attractive for families just looking to try out the sport. (This is the brand that MY son rides, so I might be a bit biased).

They have two different models across sizes–the Swift and the Sprinter. The latter is $100 more but has upgraded components and comes in a little lighter.

DK Lineup

Bike	Size	Price	Weight	Top Tube	Wheels/Tire	Crank
Swift Micro	Micro Mini	$350	16.3 lbs	16.25″	18 x 1”	120mm
Swift Mini	Mini	$350	16.3 lbs	17.25″	20 x 1-1/8”	140mm
Swift Junior	Junior	$350	17.3 lbs	18.25″	20 x 1-3/8”	155mm
Swift Expert	Expert	$350	20 lbs	19.5”	20 x 1-3/8”	165mm
Sprinter Micro	Micro Mini	$450	15.9 lbs	16.25″	18 x 1”	120mm
Sprinter Mini	Mini	$450	16.1 lbs	17.25″	20 x 1-1/8”	140mm
Sprinter Junior	Junior	$450	17.1 lbs	18.25″	20 x 1-3/8”	155mm
Sprinter Expert	Expert	$450	18.5 lbs	19.5”	20 x 1-3/8”	165mm

GT

GT offers two series of kids BMX bikes: the Mach One and the Speed Series. The Mach One is intended as an affordable, entry-level race bike, while the Speed Series is meant for some serious racing.

GT Lineup

Bike	Size	Price	Top Tube	Wheels/Tire	Crank
Mach One Mini	Mini	$425	17″	20 x 1-1/8″	140mm
Mach One Junior	Junior	$425	18.5″	20 x 1-3/8″	152mm
Mach One Expert	Expert	$425	20.75″	20 x 1-3/8″	140mm
Speed Series Micro	Micro Mini	$795	16″	20 x 1-1/8″	127mm
Speed Series Mini	Mini	$795	17.5″	20 x 1-1/8″	135mm
Speed Series Junior	Junior	$795	18.5″	20 x 1-3/8″	135mm
Speed Series Expert	Expert	$795	19.5″	20 x 1-3/8″	165mm
Speed Series Expert XL	Expert XL	$795	20″	20 x 1.5″	165mm

Haro

Haro is well known for their freestyle and street BMX bikes, but they make great race bikes as well. Most of these bikes have a v-brake, but the Expert XL even offers a rear mechanical disc brake.

Bike	Size	Price	Weight	Top Tube	Wheels/Tire	Crank
Annex Micro Mini	Micro Mini	$439	15 lbs	16.75″	18 x 1″	130mm
Annex Mini	Mini	$439	16 lbs	17.75″	20 x 1 1/8″	145mm
Annex Junior	Junior	$439	16.7 lbs	18.3″	20 x 1 1/8″	155mm
Annex Expert	Expert	$439	16.9 lbs	18.87″	20×1 3/8″	170mm
Micro Mini	Micro Mini	$549	15.5 lbs	16.75″	18 x 1″	130mm
Mini	Mini	$549	15.7 lbs	17.6″	20×1 1/8″	130mm
Junior	Junior	$549	16.3 lbs	18.3″	20×1 1/8″	145mm
Expert	Expert	$549	16.8 lbs	18.87″	20×1 3/8″	155mm
Expert XL	Expert XL	$619	19.4 lbs	20″	20×1.65 F/ 20×1.50 R	170mm

Redline

Redline is one of THE original names in BMX. Like most of the other brands listed here, Redline offers two product lines: the entry-level MX and the higher-end Proline.

Bike	Size	Price	Top Tube	Wheels/Tire	Crank
MX Mini	Mini	$450	18″	20 x 1-1/8″	140mm
MX Junior	Junior	$450	18.5″	20 x 1-1/8″	155mm
MX Expert XL	Expert XL	$450	20″	(F) 20 x 1.6″ / (R) 20 x 1.4″	170mm
Proline Micro	Micro	$480	16.5″	18 x 1″	130mm
Proline Mini	Mini	$560	17.5″	20 x 1-1/8″	140mm
Proline Junior	Junior		18.5″	20 x 1-1/8″	155mm
Proline Expert	Expert	$630	19.5″	20 x 1-3/8″	165mm
Proline Expert XL	Expert XL	$630	20″	20 x 1.60″	170mm

Jet

Jet offers simple, entry-level race bikes. This is a UK company, but you can get their bikes in the US via SourceBMX.

Bike	Size	Price	Top Tube	Wheels/Tire	Crank
Accelerator Mini	Mini	$339	17.5″	1-1/8”	140mm
Accelerator Junior	Junior	$339	18.5″	1-1/8”	150mm
Accelerator Expert	Expert	$339	19.75″	1-3/8”	160mm

Chase

Serious racers (and those with no budget), take note. Chase makes some of the nicest BMX race bikes around.

Bike	Size	Weight	Top Tube	Wheels/Tire	Crank
Edge Micro	Micro Mini	15.4 lbs	16.25″	18 x 1″	130mm
Edge Mini	Mini	16.7 lbs	17.25″	20 x 1-1/8″	140mm
Edge Junior	Junior	17.5 lbs	18.75″	20 x 1-1/8″	155mm
Edge Expert	Expert	18.6 lbs	19.75″	20 x 1-3/8″	165mm
Edge Expert XL	Expert XL	19.5 lbs	20″	20 x 1.60″ F / 20 x 1.40″ R	170mm
Edge Element Expert	Expert	18.4 lbs	20″	20 × 1-3/8″	165mm

Supercross

If you are interested in building up a bike from the frame, check out Supercross. These frames aren’t cheap, but they do give you the option to create an amazing custom build.

Frame	Size	Price
Envy Micro	Micro Mini	$650+
Envy Mini	Mini	$650+
Envy Junior	Junior	$650+
Envy Expert	Expert	$650+
Envy Expert XL	Expert XL	$650+

Things To Know Before Buying

Wheel And Tire Size

Most kids BMX bikes have 20 inch wheels. The exception is the micro mini bikes which have 18 inch wheels. (And cruiser bikes which have 24 inch wheels).

Tire width is the other thing to consider. The skinnier the tires, the lighter they will be. Fatter tires, on the other hand, provide additional traction.

You want to consider the type of track your child will be racing on. Many tracks have concrete start hills and paved corners. In this case, you can get away with skinnier tires. If the track is entirely dirt, than you may want a little wider tire with more traction for the corners.

Top Tube Length

Not all bikes that are “Minis” will have the same top tube length. The longer the top tube length the further the reach and the bigger the bike will essentially feel.

This means that if your child is on the bottom end of a size range, look for a bike with a shorter top tube length. Or, if your kiddo is on the bigger end but not yet ready to size up, consider a bike with a longer top tube length.

It’s also worth mentioning that different riders may prefer different fits. Some kids will prefer to be more stretched out in a more aggressive position, while others may prefer to be more upright. Again, trying some loaner bikes before buying can be helpful for this.

Crank Length

We see way too many kids riding a bike with crank arms that are too long. This can rob your child of power as well as simply being unergenomic.

The best way to determine which size crank length your child needs is to measure their inseam. Even if the bike you are considering has the wrong size cranks, this is always something you can swap out on your own.

Rider Inseam	Appropriate Crank Length
16″	120mm
18″	130mm
20″	140mm
21″	145mm
22″	150mm
23″	155mm
24″	160mm
25″	165mm
26″	170mm

Gearing

BMX race bikes only have a single gear. This means that it needs to be the “right” gear, or your child will be spun out or struggling to turn over the pedals.

The good news is that you don’t need to worry about this too much when buying a bike, because you can always swap out the front or rear sprocket later. Still, most kids will want to run one of the combos below. (The first number is the number of teeth on the front chainring and the second number is the number of teeth on the rear cog).

44/16
39/14
36/13
33/12
25/9

Note that these are for 20″ wheels.

Weight

Remember, the heavier a bike is the more challenging it is going to be for your child to race on. The lighter the bike, the faster they’ll be able to go.

Of course, the lighter a bike, generally the more expensive the bike will be. In fact, serious racers will spend a lot of time and money upgrading components to build a bike as light as it can be.

Choose the lightest bike that is realistically within your budget.