How to measure the size of a wheel on a bicycle

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How to determine the diameter of a bicycle wheel

From time to time the question arises: “What is the diameter of the wheels of the bicycle?”

Most often, it pops up in case a tire has broken through or new rubber is needed on the wheel of an old bicycle. And to the seller’s question “What wheel does your bike have?” only one answer comes to mind: “round”.

First of all, you need to decide on the concept of wheel diameter.

For most ordinary people, this is the diameter of the wheel along the outer (outer) border of the tire.

But there is also the concept of the landing size of the rim. this is the diameter of the rim itself or the tire along the inner border.

For the sake of brevity, here is a figure with an explanation of what is measured in each labeling system. Therefore, it is important to understand what we are measuring and what we want to find.

What are the sizes of bicycle wheels?

Wheel sizes depend on bike models, their intended use and the age of the owner. So, for children’s and teenage bicycles, sizes up to 20 and 24 inches with a wheel size in millimeters 508-609 are typical. Special bicycles, the so-called mountain bikes, have a wheel size of 26 inches and 660 mm. General purpose bicycles are road bicycles, often equipped with wheels of 28 inches and 711 mm. We should also highlight the category of mountain bikes, with a large size, they have 29 wheels. What is the size in millimeters? That’s right, 736 mm.

To calculate how much a 16-inch wheel will be in centimeters, you need to multiply this value by 2.54 and you get 40.64 cm, and a 10-inch wheel, how many cm?. 10×2.54 = 25.4 cm!

Below are the wheel sizes for kids bicycles.

The dimensions of the wheels of bicycles for a child are most often the following dimensions:

  • wheel diameter 12 inches in cm will be equal to 30.48, age 3 years;
  • a wheel diameter of 14 inches in cm will be equal to 35.56, age 3-5 years;
  • a wheel diameter of 15 inches in cm will be equal to 38.1, age 4-5 years;
  • wheel diameter 16 inches in cm will be equal to 40.64, age 4-6 years;
  • wheel diameter 18 inches in cm will be equal to 45.72, age 5-6 years;
  • wheel diameter 20 inches in cm will be 50.8, age 6-8 years;
  • wheel diameter 24 inches in cm will be 60.96, over 8 years of age.

Effect of wheel size on bike speed

There is a direct relationship between the speed and the diameter of the wheel.

From a physical point of view, the larger the wheel size, the more distance you can drive:

  • Let’s say if a bike is 29 inches, then it will be much faster and more practical than a 20 inch.
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However, this dependence is also counterproductive in another way. The smaller the wheel diameter, the faster you pick up speed. This is the main advantage of children’s bicycles, which, with an equal load, can accelerate to the same distance as an adult on a road bike.

However, keeping the speed will be more difficult, you will need to constantly pedal. On 26-29 inch models, the distance is covered faster, acceleration will be slow, but the speed remains longer.

20-inch wheels

  • Rim diameter: 406.
  • Children’s bike for height from 120 to 140 cm.
  • Weight up to 40 kg.
  • Folding mechanisms are suitable for the initial stage in riding training.
  • A good option for children from 5 to 9-10 years old who have only recently driven.
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How to choose a wheel for a bike

The wheel of a bicycle is its most important part, which has a huge impact on characteristics such as weight, acceleration, speed, maneuverability, cross-country ability, traction, etc. Therefore, the selection of this essential cycling element must be taken with the utmost seriousness and care. This article is for beginner cyclists to help them choose the right wheels.

When choosing a wheel, you need to pay attention to its size, weight and strength. If everything is clear with weight and strength, the lighter and stronger the better, then the size is not so simple. It cannot be said unequivocally that one size or another is better than another for all cases. Therefore, when choosing a size, a beginner cyclist may be puzzled, but there is nothing difficult here either, this parameter depends on the scope of the bicycle. Also, no need to howl about wheel size compatibility with the fork and frame is great.

We will talk more about the choice of wheel sizes in the third chapter, and now we will focus on weight and strength. It is clear that the lighter and stronger the wheel, the better, but what does it depend on? Weight and strength depends on the shape of the profile and the material of the rim, as well as on the thickness of the spokes and the quality of the tires.

A bicycle rim can be single, double or triple profile. There are also special modifications for tubeless.

When choosing a profile shape, we recommend paying attention to double rims. Today, most normal branded amateur bikes are equipped with double rims, they are stronger than single rims, usually lighter than them and are compatible with any type of brakes. High strength is provided by the second baffle, and the lower weight is due to the use of aluminum alloys, in contrast to single ones, where heavy steel is used.

Triple. the most durable, but also the most difficult modifications that are rare.

Tubeless rims are manufactured using UST (Universal System Tubeless) or BST (Bead Socket Technology) technology.

Profile height and width also affect strength. The higher the profile, the better its folding strength and resistance to frontal impacts, the wider it is, the higher the torsional rigidity. The high profile suffers less from driving over pits and bumps, therefore it is recommended for those who drive on bad roads and light off-road hardtails.

How To Read a Bike Tire Size

For lovers of tricks and jumps and those who like to drive off-road, it is better to choose a profile of great height and width, since in these cases there are enough blows from all sides.

The following materials are used in the manufacture of rims:

  • aluminum alloys;
  • steel;
  • chrome-molybdenum steel;
  • carbon.

For most novice amateurs, aluminum models can be recommended. They are lighter, and sometimes even stronger than conventional steel, due to the special shape of the profile and heat treatment. over, they are more expensive than conventional steel.

Steel has been manufactured for decades. They are quite durable and cheap, and it is easier to fix the “eight” set when hitting the curb. The disadvantages are heavy weight and susceptibility to corrosion. Good option for budget single speed bikes with drum coaster brakes, but not V-brake compatible.

The addition of chromium and molybdenum to steel significantly improves its strength characteristics, therefore heat-treated chromium-molybdenum models are appreciated among fans of extreme stunts and jumps, as well as those who drive off-road or descend at high speed from a mountain slope. Great option for a BMX or two-suspension bike.

Carbon fiber modifications are ideal for riders. Very lightweight and durable material, which is very expensive, so many hobbyists cannot afford it.

To simplify this task, experts have compiled tables with bicycle wheel sizes and implemented a traditional marking system. We will tell about them.

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How To Determine Wheel Size For A Bike Computer BikeBlogger

The most important wheel parameters are:

  • external diameter;
  • rim and tire width.

The most common unit of measurement is inches. Sometimes there are millimeter markings, this usually applies to road, hybrid, and sometimes city models. Most common diameters: 20 “, 24”, 26 “, 27”, 27.5 “, 28” and 29 “.

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The marking is indicated on the side of the tire, the inscription 26×1.75 means that the wheel diameter is 26 inches, width is 1.75 inches.

When choosing a rim and tire, you need to pay attention to the rim fit and tire diameter. The rim diameter is 406, 507, 559, 584 and 622 millimeters. over, the size of 622 mm is designed for 27 ″, 28 ″ and 29 ″ tires at the same time. In this case, a larger wheel diameter is obtained due to the higher tire height.

How to Read Bicycle Tire Sizes

To avoid confusion with the dimensions, below we give a plate in which we indicate the marking universal ISO dimensions for various types of bikes.

Base table

Universal values ​​that can be used for initial estimates.

Baby

Of course, it doesn’t matter to a child what size of the frame, and on any frame it will be inconvenient for him in six months, but buying bicycles “for growth” is still not worth it if the health of the baby’s joints is expensive.

Road bikes

Usually, buyers of such bicycles know which model and what size they need, but everything happens for the first time, and even professionals should find out the standard sizes.

Size charts

Each size table below will help you determine the range of models you are interested in, but the main thing to know is that no size can be determined accurately. 18 or 24 inches is the manufacturer’s estimate of a very specific distance. for example, the length of the seat tube, or the distance from the center of the carriage to the junction of the extensions of the upper tube and the steering column. there can be many measurements!

Therefore, it is very dangerous to buy a bike over the Internet or “by eye”. any bike should be tested in action, sit on it, feel the maximum distance from the seat to the pedals.

Features of frame types

What should you pay attention to when choosing a bike? Consider the recommendations for the type of frame.

  • Versatile cross-country. The straight and clear frame makes this type a reference. When choosing, we use a universal rule and carefully look at the stem and the configuration of the saddle. They can be “unexpected” in size and seriously change the configuration.
  • Road bike frames need to fit perfectly, as every inch of leverage on a moving body directly affects power and speed. It is important to pay attention not only to the configuration and length, but also to the handlebars, which take on a very large load corresponding to the weight of the athlete.
  • For downhill and mountain bike frames, it is especially important to leave safety distances both under the saddle and at the level of the handlebars. it makes no sense to select a configuration that will interfere with a sudden fall or full activation of the fork.
  • Cruisers. The main thing is convenience. Pay attention to the position of the saddle and arms. It makes no sense to look at the nominal dimensions, since even within the model range of one manufacturer they may differ.

General recommendations for selection

Universal rule

The general rule of thumb is to test any bike before moving on to testing different types of fit. The same rule will help you quickly choose the size of the frame.

So, you should stand over the bike frame so that the saddle rests on your back, and relax. At this point, the distance between the top tube of the frame and the crotch should be between 5 and 15 centimeters.

Too much distance will reduce the stability of the bike on the track and most likely corresponds to a too short base, and too little will create inconvenience and a greater likelihood of injury.

Bike settings

To view or change bike settings, go to SETTINGS Bike settings. bike and select bike. The sensors you have connected to the bike are displayed under the bike name.

BIKE NAME: Bicycle 1. Bicycle 2. Bicycle 3 or Bicycle 4.

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WHEEL DIAMETER (MM): Set the wheel diameter in millimeters. See Wheel Diameter Measurement for more information.

CONNECTING ROD LENGTH (MM): Set the connecting rod length in millimeters.

SENSORS: View all sensors connected to the bike.

Measuring wheel diameter

Accurate wheel diameter data is a must in order to know your ride. There are two ways to determine the diameter of your bike’s wheels:

Measure the wheels manually for the most accurate result.

Use the valve to determine the point where the wheel touches the ground. Draw a line on the ground to mark this point. Drive your bike forward on level ground until the wheel completes a full circle. The tire should be perpendicular to the ground. When the valve is at the starting point, drag another line near it to mark a complete revolution. Measure the distance between two lines.

Subtracting 4mm from this distance to compensate for your pressure on the bike will give you the wheel circumference. Enter this value into your cycling computer.

Find a marking on the wheel indicating the wheel diameter in inches or ETRTO units. Use the table to get the value in millimeters (right).

Wheel size data can also be obtained from the manufacturer.

ETRTO Wheel diameter (inches) Wheel diameter setting (millimeters)
25-559 26 x 1.0 1884
23-571 650 x 23C 1909
35-559 26 x 1.50 1947
37-622 700 x 35C 1958
47-559 26 x 1.95 2022
20-622 700 x 20C 2051
52-559 26 x 2.0 2054
23-622 700 x 23C 2070
25-622 700 x 25C 2080
28-622 700 x 28 2101
32-622 700 x 32C 2126
42-622 700 x 40C 2189
47-622 700 x 47C 2220
55-622 29 x 2.2 2282
55-584 27.5 x 2.2 2124

The values ​​in the table are only approximate, as the wheel size also depends on the wheel type and air pressure. Due to different measurement data, Polar cannot be held responsible for their correctness.

Quantities, Units and Conventional Markings

When determining the parameters of the wheel, the following values ​​are measured:

  • Outer wheel diameter;
  • Rim and tire widths.

It is customary to use inches as the unit of measurement. However, albeit rarely, but you can still find markings in millimeters. The most common sizes: 20 ″, 24 ″, 26 ″, 27 ″, 27.5 ″, 28 ″ and 29 ″. these are the numbers traditionally indicated on the rims and indicate the diameter. Type marking diameter x width is indicated on the side of the rubber, for example 26×1.75.

Important: in some cases, instead of a dot, they write the sign of the fraction 26×1¾, and although this is mathematically equal to 26×1.75, such tires are not interchangeable.

It is useful to know that the rim diameter is found in only five variations: 406, 507, 559, 584 and 622 millimeters. In this case, 622 mm is intended for 27 ″, 28 ″ and 29 ″ tires. The use of rims with a smaller bore diameter is not provided for them.

Bicycle Wheel Selection. Size Chart

The wheel is the most important part of the bike. When choosing it, you should rely on two parameters: weight and size. And if the weight is easy to determine. what is easier is better, then when choosing a size, the cyclist may be puzzled, because this characteristic directly depends on the scope of the bike. To simplify this task, experts have compiled tables with bicycle wheel sizes and implemented a traditional marking system. We will tell about them.

International Organization for Standardization (ISO) Marking

To eliminate confusion with parameters, a universal ISO marking system has been developed. All manufacturers use it.

This marking is based on two values:

  • Tire width (dm);
  • Width of the landing diameter of the landing rim (mm).

When choosing a rubber, it is necessary to pay attention to the landing diameter: it must necessarily coincide with the original parameters of the bicycle rim. So, 29-622 29-622 tire is interchangeable with 27-622 road, despite the fact that their width is different.