Ultimate Size Guide For BMX Bike-BikeTroops

As a whole, BMX is thought of as a simple bike. We can tell you the difference between a store disaster and a machine made for a specific purpose. Most people can’t tell you the difference, but we know better! All of us know what it takes to make BMX bikes strong enough to withstand the kind of punishment we give them. We know that not all BMX bikes are the same.

1. WHAT SIZE FRAME DO I NEED FOR MY NEW BMX BIKE? 

This is the first question we all ask ourselves when buying a bicycle or choosing it for a family member. It must be borne in mind that there are more sizes in our discipline than in any other cycling modality. Normally the size of the frame is associated with a name (Micro, Mini, Junior, Expert, etc.). In addition, we can find bicycles with 20 “wheels (the most widespread) and 24” (the so-called Cruiser). We will focus on 20 “bikes. Using the following table and taking into account the height and weight of the rider, you can have a first idea of ​​what size to choose.

Frame sizeMiniJuniorExpertExpert XLPro / Jr ProPro XLPro XXL
Rider weightLess than 30 kg25 – 36 Kg30 – 45 Kg35 – 50KgMore than 45 KgMore than 60 KgMore than 70 Kg
Rider height115 – 140 cm130 – 145 cm135 – 145 cm145 – 160 cm155 – 170 cm170 – 180 cmMore than 175 cm
Frame size16 – 17,5″17,5 – 18,5″19,25 – 20″19,5 – 20″20 – 20,5″21 – 21,5″21,5 – 22″
Connecting rods145 – 155 mm155 – 165 mm165 – 170 mm170 – 175 mm175 – 180 mm180 – 182mm180 – 185 mm
Power sizeMiniMini / Mini XLExpert / ProExpert / ProProPro / XLPro XL / XXL
Handlebar size2 – 2,25″4 – 5,5″5 – 6,5″6 – 7,25″7 – 8″7,5 – 8″8 – 8,8″
Video Guide On What Size BMX Will You Need

2. WHAT SIZE COVERS DO I NEED FOR MY BMX BIKE?

Normally, the size of the frame is matched by the dimensions of the covers. For example, an Expert size bike usually comes out with 20×1-3 / 8 “tires. However, the following table indicates the recommended rider weights for each tire size.
Tire and tire size:

Rider weight (Kg)Rider’s age (years)Recommended size
25 – 355 a 1020 x 1-1/8
35 – 509 a 1020 x 1-3/8
50 – 6012 a 1420 x 1,50
Over 6514 and up20 x 1,75

BMX wheels measurements:

12 “wheels for children from 3 years old who want to learn BMX.
16 “WHEELSBMX fans up to approximately 1m tall.
18 “WHEELSBMX fans up to approximately 1.30m tall.
20 “WHEELSBMX fans from 1.30m tall.

3. WHAT SIZE OF CRANKS DO I PUT ON MY BMX BIKE?

As in the previous section, normally each frame size already comes with standardized cranks at that size, but depending on the rider’s crotch height, they may be more comfortable with larger or smaller cranks. Be careful, it must be taken into account that, for the same development, the smaller the connecting rods, the more it will cost to move said development. In other words, the moving development of a 36 chainring with a 16 sprocket will cost more with 130mm cranks than with 150mm cranks. The following table indicates the recommended crank size according to the rider’s crotch measurement.

Micro Mini, Mini, Junior

Crotch Height (inches)Crotch Height (cm)Connecting rod length (mm)
15 – 1638 – 40,5130
16 – 17,540,5 – 44,5135
17,5 – 1944,5 – 48140
19 – 2048 – 51145
20 – 2251 – 56150

Junior, Expert, Expert XL

Crotch Height (inches)Crotch Height (cm)Connecting rod length (mm)
20 – 2251 – 56150
22 – 2356 – 58,5155
23 – 2558,5 – 63,5160
25 – 2663,5 – 66165

Junior Pro, Pro, Pro XL/XXL

Crotch Height (inches)Crotch Height (cm)Connecting rod length (mm)
25 – 2663,5 – 66165
26 – 2766 – 68,5170
27 – 2968,5 – 73,5175
29 – 3073,5 – 76177
30 – 3276 – 81180
Over 32Over 81182 – 185

4. PLAYING WITH MY BMX DEVELOPMENTS

Developing Your bmx bike

We reached the most difficult point. What chain wheel/pinion gears do I use? This section already depends more on the physical state of the cyclist and his needs than on some theoretical parameters. It all depends on whether we are looking for an agile bike on the grid and corner exits or whether we are looking for a bike with a good top speed to take advantage of them on the straights. The following table indicates how many meters we travel with each pedal stroke on a 20 “bicycle. The size of the tire has not been taken into account but it is a good basis for testing. Say, the higher the number of development, the more it will cost to move it from standing. Check our bike tune-up article for fore info.

Development for a 20 “BMX bike. The size of the tire is not taken into account but the size of the rim itself (51 cms.)

Chainring / Pinion1112131415161718
324,664,273,943,663,423,203,022,85
334,814,414,073,783,523,303,112,94
344,954,544,193,893,633,403,203,03
355,104,674,314,013,743,503,303,12
365,244,814,444,123,853,603,393,20
375,394,944,564,233,953,713,493,29
385,535,074,684,354,063,813,583,38
395,685,214,814,464,173,913,683,47
405,835,344,934,584,274,013,773,56
415,975,475,054,694,384,113,863,65
426,125,615,184,814,494,213,963,74
436,265,745,304,924,594,314,053,83
446,415,875,425,044,704,414,153,92

5. CLOTHING MESUREMENT FOR BMX RIDING

PANTS FOR BMX RIDING

When in doubt between two sizes, it is always recommended to choose the higher size.

Take your waist measurements, loosely, in a normal position and without shrinking your belly.

Bear in mind that Enduro / Cross pants are often elastic and therefore are measured according to the XS, S, M, L, XL, XXL scale.
MAN

SizesXSSMLXL2XL3XL4XL
USA2830323436384042
International4648505254565860
Waist768084889296100120cm
Hips9296100104108112116120cm
Int length Leg76.281.386.491.491.496.596.589-92cm
Height174177180183186189192195cm

CHILDISH

USA2022242628
Italy4681012cm
CHEST6064687378cm
WAIST5457606468cm
HIPS6469747984cm
HEIGHT98-109109-120120-131131-145145 – 159cm

GLOVES FOR BMX RIDING

SizesXSSMXL2XL3XL
Mano18-2020-2121-22,522,5-2424 – 25.527 – 28.5cm

HELMETS FOR BMX RIDING

SizesXXSXSSMLXLXXL
Head circumference51–5253-5455-5657-5859-6061–6263-64cm

MEN’S T-SHIRTS FOR BMX RIDING

SizesXXSXSSMLXL2XL3XL4XL
Sizes444648505254565860cm
Chest85 – 8889 – 9395 – 99101 – 105107 – 111113 – 117119 – 123125 – 129131 – 135cm
Waist73 – 7779 – 8385 – 8991 – 9597 – 101103 – 107109 – 113115 – 119cm

CHILDREN’S T-SHIRTS FOR BMX RIDING

InternationalXSSML
Chest59-6365-6971-7578-83cm
Waist53-5657-6062-6668-72cm
Hips62-6769-7477-8184-89cm
Height95-111111-127127-147147-162cm

FRAUD FOR BMX RIDING

S / ML / XXLXXL
Height160 – 172172 – 184184 – 186Cm
Height5.2” – 5.8”5.8” – 6”6” – 6.5”Inches

FAQ

What age is a 20 inch BMX bike for?

The number is 20 “The wheel turns. There are BMX bikes for all ages, but the minimum age for this type of bike is between 7 and 8. There are mountain bikes. You should be able to stand flatfooted on the ground and have at least three “a space between you and the frame’s top tube (crossbar).

How do you size a BMX bike?

A frame’s size is determined by measuring the length of the top tube of the frame, which is called the top tube length. To measure the top tube, you take a line from the centre of your seat tube to the centre of your head tube. To figure out your frame size, you need to measure your height. Remove your shoes and anything else from your head.

How tall should you be for a 20 inch BMX bike?

Flat 20inch BMX bikes are best for people who are taller than 155cm. So many BMX frames are out there that it can be hard to choose the right one because the size of the bike can affect how you ride.

What size BMX bikes do adults use?

Adults ride what size BMX bikes. Most adults ride BMX bikes with a frame size of more than 20 inches. It can be up to 21.5 inches for the top tubes. 22-24, and 26 are some of the bigger sizes.

What age is a 24-inch bike for?

For kids ages 8, 9, and 10, 24-inch bikes are usually the best choice. Check out our bike sizing guide if you aren’t sure what size bike is best for your child. The form and function of kids’ 24-inch bikes can be very different, just like with adult bikes.

What size BMX should I buy?

People who are taller than average will have a better time riding a bike that is the right size for them. There are two factors that determine how big a BMX bike is. The first is the diameter of the wheels, and the second is the size of its frame (this value is set by the length of the Top-tube, “TT”).

Are BMX supposed to be small?

No, BMX bikes are meant to be small. … Their small sizes are the same size as Road bikes. The weight makes most of them look small. They’re usually light because they don’t have too many parts.

FINAL THOUGHTS ON BMX BIKE SIZE GUIDE:

1. If the rider is still growing, consider purchasing a size larger.

2. Fine-tuning is based on personal preference, riding style, and experience.

3. The distance between the rider’s crotch and the bike’s top tube should be 1 to 2 inches for safety and comfort.

Don’t waste your money

Finding the right BMX bike might be an uphill battle. Especially when you take into account all of the various specifications that influence the riding style and abilities of the rider.

As a means of easing the learning curve and advancing my goal of popularizing BMX through an approach that emphasizes both enjoyment and understanding, I’ve decided to.

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