# How to measure the diameter of a children’s bicycle wheel

## Choosing a bike by height (choosing the size of the bike frame).

Online ordering of bicycles is becoming more and more popular. Don’t worry about having to try on the bike in person first. This approach is very overrated! City bikes and cruisers often have no height differentiation at all and are positioned for cyclists with an average height of 155-180 (women) or 165-190 (men).

There are many good methods for choosing a sports bike to choose the right one, below we will take a look at the one we use ourselves. The size of the bike is measured from the beginning of the seat to the bottom bracket, as in the image below.

Take off your shoes and stand with your feet about 15-20 cm apart (shoulder width apart). Measure the height from ground to crotch. Decide on the type of bike you need: mountain bike, city bike, or road bike. Now you can take a calculator and calculate the size you want:

City bike. leg (cm) x 0.685 = your frame size

Mountain bike. leg (cm) x 0.66 = your frame size

Road bike. leg (cm) x 0.70 = your frame size

For example, if your leg is 76 cm long, then the correct size for a mountain bike is 50 cm or 20 inches, a road bike is 53 cm, and a city bike is 52 cm.

### How to size a kids’ bike with Sir Chris Hoy Toby Investigates

For generalization and convenience, below is a table that can be used when selecting a mountain bike.

Rider Height (cm) Leg Length (cm) Recommended Frame Size
145-158 60-73 13 “/ 14” XS 33-36
155-172 63-76 15 “/ 16” S 34-40
168-182 66-78 17 “/ 18” M 43-47
178-190 68-81 19 “/ 20” L 48-52
185-200 71-83 21 “/ 22” XL 55-58
200-210 73-86 23 “/ 24” XXL 59-62

This table is most relevant when choosing a mountain bike with no rear suspension. When choosing a bike with a rear shock absorber, the geometry may differ depending on the purpose of the frame. In this case, it is best to check the information on the manufacturer’s website. At the same time, the size of a modern bicycle will be the same for a mountain bike with 26 “wheels, including fat bikes, and for a mountain bike with 27.5” wheels, and for a bicycle with 29 “wheels.

Hybrids, road bikes, cyclocross bikes, gravel bikes, road bikes and track bikes all have different geometries, which makes the size chart different for them. On average, the sizes of different brands and directions can be combined into one table:

Cyclist Height (cm) Recommended Frame Size
145-158 XXS 47-50
157-163 XS 49-51
163-170 S 51-54
170-178 M 55-57
178-183 M / L 57-59
183-190 L 58-60
190-200 XL 61-64

The height of the saddle extending from the seat tube is important when choosing a sports bike. Even a couple of centimeters in saddle height can affect pedaling power by up to 50%.

Bike Model Recommended Height (cm)
Stels Pilot 3 / Desna 2100 140-180
Stels Pilot 4 (7) / Desna 2200 (2500) 150-200
Forward / Altair 150-200
Shulz hopper 140-180
Shulz (other bikes) 150-200
Author 150-195
Strida LT, 5.2 153-193
Strida SX, SD, C1 160-200
Giant / Dahon / Dewolf 160-180
Langtu (14-18 “) 140-180
Langtu (20-24 “) 150-200
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Unlike adult bicycles, which have different frame sizes depending on the rider’s height, children‘s bicycles are measured by the size of the wheel. You can read more about the selection of a children‘s bike at the end of the article, but you can average in one table:

Child’s age (years) Height (cm) Wheel diameter (inches)
1-3 Up to 95 Up to 12 “
2-4 85-105 12″
2-5 95-110 fourteen”
4-6 100-115 sixteen”
5-8 100-120 eighteen”
7-9 115-135 twenty”
9-11 130-145 24 “
From 10 From 140 26 “

Problems when choosing an unsuitable bicycle size and options for solving them There are elements of a bicycle that you also need to pay attention to when choosing a size: handlebar stem, handlebar and seatpost and the position of the saddle in it.

If you have already bought a bike that is too big, the fit can be slightly corrected by replacing the stem with a shorter stem or by extending the saddle in the “rails” to a position closer to the handlebars.

If the size is too small, the problem can be corrected by installing a longer stem with a wide handlebar or replacing the seatpost with a longer one with a backward bend.

### Age from 18 months / balance bikes (bike runs, balance bikes)

Balance bikes are designed for children aged 18 months and older and teach balance, fine motor skills and good habits. These bicycles have no pedals and are propelled by a child pushing himself with his feet. These bicycles are the easiest to learn to balance, and by themselves they are the lightest of children‘s bicycles. There are balance bikes with wheel diameters ranging from 10 to 20 inches. Wheels can be plastic with EVA tires or inflatable rubber. The former are much lighter, but have good grip only on hard or tamped surfaces. If you plan to ride outside the city, it is better to choose a balance bike with inflatable wheels.

### Age 7.9 / wheel size 20 inches

20 “is the most popular kids bike size on the market. In addition, it is at this stage that children usually really begin to feel the bike and understand the feeling of freedom to ride it. This bike is suitable for a height of 115-135 cm or for those who are between the ages of seven and nine.

Already at this stage, bicycles begin to be clearly classified into disciplines such as mountain bike or MTB, road bike and extreme bike or BMX.

Children’s mountain bikes may contain the same technologies as adult sports ones: rear suspension, a large number of gears, disc brakes. However, the rear suspension adds a significant portion of the bike’s weight and reduces its durability, or it will cost the same as a good adult sports bike. The front suspension provides shock absorption and more control in difficult terrain, so only needed in difficult terrain. Therefore, for city driving, we recommend considering options without a suspension. In a city with such a flat terrain as St. Petersburg, a large number of speeds is also not necessary, because this greatly complicates the design of the bicycle and affects the durability. Road bikes with 20 ”wheels generally have narrower flat tread wheels. Comfort models come with full-size rigid fenders, wide saddle and footrest. Sports road bikes sometimes even have a ram bar and a large number of speeds.

BMX kids’ bikes are a popular option because they have a large margin of safety and often have a simple but striking design. Also, a big plus is that if a teenager likes BMX as a sport, he will be able to ride his first BMX for a rather long time, because adult bicycles have the same wheel diameter and similar geometry.

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### Age 4.6 / wheel size 18 inches

Just as a 14-inch bike is an alternative to a 12-inch bike, an 18-inch bike is an alternative to a 16-inch one. A bicycle with 18 ” wheels is suitable for height from 100 to 120 cm and ages from 4 to 6 years.

### Age 4.6 / wheel size 16 inches

This bike can be the next step after a bike with a wheel diameter of 12 or 14 inches, and immediately after a balance bike. Wheels with a diameter of 16 inches are suitable for height 100-115 cm or ages from 4 to 6 years.

The frame of such a bicycle can be made of steel or aluminum. Aluminum is lighter and less prone to rust, but more expensive. Many bikes of this size have only a rear coaster brake for simplicity’s sake. Sometimes complete with a front handlebar, but some bikes have both brakes with handlebars. Children of this age have sufficient strength to use these brakes, but before purchasing, we recommend that you ensure that the brake lever is specifically designed for small hands.

## The relationship between height and diameter

It is wrong to think that wheel size only affects the driving behavior of your two-wheeled vehicle. Growth is also very important here. Consider in what features this is manifested:

It is worth noting that if you are guided by height when choosing a bike and its parts, then you should observe not only the size of the wheel, but also the size of the bike frame, and in some cases, use the stem in addition to create the most comfortable driving conditions. Some experts recommend taking into account, in addition to growth, the length of the legs, because it is they who get tired the most during the movement and need careful care.

## Relationship between wheel diameter and driving characteristics

Consider some options for how the size of a bicycle wheel can affect driving.

• The larger the wheel of the bicycle, the more effort and energy it takes to spin it. Therefore, you will have to train your endurance and pump up your legs. But at the same time, the achieved rotational speed will be much higher and better than in the case of a lower.
• Large wheels are more convenient to use on smooth and level roads. A 29-inch size would work well here. For mountain bikes with frequent stops, go for smaller rims. for example, 26.
• As for the width of the tire, here the passability on difficult areas. for example, stones or rocks. depends on its width. If you are choosing wheels for just such a case, then give preference to small models with a minimum width of 2 inches.
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 Rim diameter in inches Rim diameter in mm Matching bikes twenty 406 Kids models, BMX 24 507 Old Soviet bikes like Salyut or Altair, teenage bicycles, bicycles for extreme sports 26 559 The most common size option often used by standard mountain bikes or city bikes 27 622 Road bikes 28 622 Old Soviet model bicycles such as Ukraine or folding Aist, as well as hybrid and road bicycles 29 622 One of the latest developments in the field of cycling. Can be used for both advanced mountain bike models and everyday riding

## Dimensions of bicycle wheels and how to correctly measure the diameter of a bicycle wheel for your height

If you decide to upgrade your two-wheeled vehicle or just change wheels, a logical question arises. which wheel to choose? Regardless of whether you want to buy a wheel the same size as yours, or give preference to something new, you need to be able to determine the diameter of the wheel. And, of course, you need to know what this indicator affects and why wheels of a larger diameter are more suitable for some people, and for others. smaller ones.

## Which option is better to choose?

If there is no controversy about the smallest wheel sizes, then it really boils about rims with a diameter of 26 and 29 inches. This is one of the most popular sizes, but in fact there are quite visible differences between them, knowing which you can easily choose the option for your bike and body.

• Bicycles with 29-inch tires pick up the required speed easily enough, handle well, just overcome obstacles, handle turns freely. But in comparison with a diameter of 26 inches, such a bicycle, on average, picks up speed only with a large expenditure of energy, so it takes more time to circle.
• The 26-inch wheels are more agile in action, pick up speed much faster and stop more easily. But as for inertia, here the rim with a diameter of 29 inches takes the palm.
• If you are looking for the option to tackle various bumps, then 29-inch wheels are your option. Since they have a large area of ​​contact with the surface, you will overcome bumps without even noticing them. Also, driving on a steep incline will give you much less inconvenience if the rim size is larger. Accordingly, on a bicycle with a wheel diameter of 26 inches, you will need to expend more energy and strength to overcome obstacles.