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/ / Bicycle Wheel Size Chart: A Complete Guide
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Bicycle Wheel Size Chart: A Complete Guide

In cycling, the bike wheel size significantly impacts the overall riding experience. The wheel size determines the bike’s speed, stability, and comfort and affects handling and the ability to adapt to different terrains. Therefore, understanding how to choose the right wheel size is crucial.

This article will provide a comprehensive bike wheel size guide, covering the basics of bike wheel sizes, the characteristics of different sizes, how to select the appropriate bike wheel size based on your needs, and how to use a Bicycle wheel size chart to make the best choice.

Bicycle Wheel Size Explanation and Marking Interpretation

When choosing bicycle wheels and tires, size is a key factor. However, the coexistence of different measurement standards and marking systems can often be confused. Understanding the relationships between wheel sizes and the true meaning of tire markings can help you avoid compatibility issues and better match your riding needs.

Mountain bikes and road bikes have significant differences in how their wheel sizes are labeled. Mountain bikes typically use inches to represent sizes, such as 26 inches, 27.5 inches (650B), and 29 inches. On the other hand, road bikes tend to rely on the International Organization for Standardization (ISO) system, using bead seat diameter (BSD) in millimeters. For instance, 622 mm corresponds to 700C, while 584 mm corresponds to 650B. These differences reflect the distinct designs and purposes of the two bike types but can also lead to confusion.

For example, the bead seat diameter of both 29-inch and 700C wheels is identical at 622 mm. However, 29-inch wheels are usually used on mountain bikes, paired with wider tires for off-road performance, while 700C wheels are mostly found on road bikes with narrower tires to optimize speed. This phenomenon, where the same size serves different purposes, can easily mislead riders, especially those unfamiliar with the ISO system.

Tire specifications are typically printed on the side of the tire, such as “700x25C” or “29×2.2”. While these markings seem straightforward, they don’t always accurately reflect the actual dimensions. For instance, “700” indicates a bead seat diameter of 622 mm, but the overall external diameter of the tire can vary depending on its width. Similarly, a “29×2.2” marking shares the same bead seat diameter as 700C but has a significantly larger external diameter due to its wider tire.

Adding to the complexity, tire sizes may vary slightly between manufacturers, even when the markings are identical. These small discrepancies can sometimes result in installation challenges. For example, a tire marked “700x32C” might not fit properly on a particularly narrow rim.

To ensure proper compatibility between tires and rims, it’s essential to understand the true meaning of the markings and focus on the bead seat diameter (BSD). BSD is the most reliable measure for compatibility, surpassing the tire’s marked diameter or width.

For example:

  • While 700C and 29-inch wheels have different labels, both share a bead seat diameter of 622 mm, allowing them to interchange theoretically. However, their tire widths typically differ, affecting installation and performance.
  • On the other hand, 650B and 700C wheels have different bead seat diameters—584 mm and 622 mm, respectively—making them completely incompatible.

Additionally, it’s crucial to check the tire’s actual width and the clearance of your bike frame and rims. Even if the bead seat diameter matches, an overly wide tire might cause rubbing or fail to install properly.

If you are not sure what your wheel size is, view How to Measure Bike Wheel Size.

Explanation of Bicycle Wheel Size Measurement Units

bike wheel size measurement units include several types, each with different representation methods and measurement techniques. The main wheel size measurement units are as follows:

  • ETRTO (Now ERTO) Sizes
  • ISO Sizes
  • JIS Sizes
  • French Sizes
  • American/English Sizes
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Notice: ETRTO size and ISO size are the same standard, just different names. They are both used to represent the dimensions of wheels and tires and are established by the European Tire and Rim Technical Organization (ETRTO) to ensure compatibility between tires and wheels.

Standard Full-Size Wheels

Bicycle wheel diameter refers to the diameter of the rim, commonly expressed in inches or millimeters. The choice of wheel diameter directly affects various aspects of the riding experience, including handling, comfort, and speed. Standard wheel diameter sizes include 26 inches, 27.5 inches, 29 inches, and 700C, each with unique characteristics and suitable applications.

26-Inch Wheel (ISO 559 mm)

The term “26 inches” does not refer to the actual diameter of the wheel itself, but rather to the approximate outer diameter of the tire that fits this rim size. Specifically, a 26-inch wheel typically refers to a wheel system equipped with 26-inch tires. The outer diameter of these tires is approximately 26 inches, but the actual inner diameter of the rim (i.e., the bead seat diameter) is usually 559mm.

Therefore, 26 inches (ISO 559mm) represents the tire’s nominal outer diameter, not the wheel’s internal structural size. The 26-inch wheel was once the standard size for mountain bikes. It offered good agility and responsiveness, making it suitable for rugged terrain. However, compared to larger wheel sizes, it lacks stability and comfort.

27.5-Inch Wheel /650B (ISO 584 mm)

Similar to the 26-inch size, the 27.5-inch wheel (ISO 584mm) is also a nominal outer diameter, referring to a tire with an outer diameter of 27.5 inches that fits this size rim. This makes the 27.5-inch wheel offer better obstacle-clearing ability and comfort compared to the 26-inch wheel, while still being more agile than the 29-inch wheel. The 27.5-inch wheel (650B) provides a balanced option for gravel and hybrid bikes, especially for riders who need a combination of handling and stability. View What are 650b Wheels?

Related reading: 650B vs 700C.

29-Inch Wheel (700C) (ISO 622 mm)

The 29-inch wheel similarly refers to a tire with an outer diameter of 29 inches fitting this rim size. This means the 29-inch wheel typically comes with larger tires. Compared to the 26-inch and 27.5-inch wheels, the 29-inch wheel is better at handling rough terrain, offering higher stability and comfort, particularly in long-distance and off-road riding. Although the rim diameter of the 29-inch wheel (622mm) is the same as that of a 700C wheel, the rims of mountain bike wheels are generally wider to accommodate the larger tires. View What is 700c wheel size?

27-Inch Wheel (ISO 630 mm)

The 27-inch wheel (ISO 630mm) is relatively rare and was once the standard size for some older road bikes. Compared to the modern 700C wheel, the 27-inch wheel has a slightly larger outer diameter, with the rim’s inner diameter measuring 630mm, which is what the “27 inches” refers to. However, compared to the 700C wheel, the design and application of the 27-inch wheel differ. The 27-inch rim is typically paired with narrower tires. Today, the 27-inch wheel is less common and is more likely to be found on vintage bikes or specific types of older models.

Extra-Large Size Wheels (32-inch/ISO 686 mm and 36-inch/ISO 787 mm)

The 32-inch and 36-inch wheels are very large sizes, corresponding to ISO standard diameters of 686mm and 787mm, respectively. They are not common bicycle rim sizes and are typically found in specialized bike designs, such as long-distance touring bikes or recumbent bikes. The advantage of these larger wheels is that they provide excellent comfort and stability, especially reducing vibrations during low-speed riding. However, due to their large size, they are not suitable for everyday use, being heavier and offering limited tire choices. Therefore, they are typically seen only on bicycles designed for specific purposes.

Children’s Bike Size Chart

  • 16-inch Wheels (ISO 305 mm): Commonly used on children’s bikes and some adult folding bikes, though they perform poorly on rough terrain and have sensitive steering.
  • 20-inch Wheels (ISO 406 mm): Standard size for BMX bikes and “small wheel” folding bikes, suitable for tricks and maneuverability but prone to impact on uneven surfaces.
  • 24-inch Wheels (ISO 507 mm): Less common, mainly used on youth mountain bikes and some BMX cruisers designed for larger riders, offering a specific geometry and maneuverability for those seeking it.

How to Choose the Right Wheel Size

When choosing the right wheel size, understanding the meaning behind different wheel and tire markings is essential. Different sizes cater to various riding needs, terrain types, and comfort preferences. Below are some key points on how to choose the appropriate wheel size, with specific examples to guide your decision.

1. Understand Wheel Markings

Wheel sizes are commonly indicated using the ETRTO standard, imperial sizes, and common road bike markings. For example, the ETRTO standard uses two numbers to represent tire width and inner diameter. The inner diameter is typically fixed, while the width varies depending on the intended use and needs. Below are two common wheel size markings explained in detail.

Example 1: 37-622 (28×1⅝×1⅜ – 700×35C)

How to Choose the Right Wheel Size-2
  • ETRTO Standard: 37-622
    • 37: Represents the tire width of 37mm, suitable for everyday riding, urban commuting, or light off-road use. This width offers good comfort and grip.
    • 622: Represents the inner diameter of the tire, which is 622mm. This corresponds to the 700C rim size, compatible with most road bikes, city bikes, and hybrid bikes.
  • English Size: 28×1⅝×1⅜
    • 28: The outer diameter of the tire is 28 inches, which is equivalent to 700C, fitting most road and city bike wheels.
    • 1⅝: The tire width is 1.625 inches (approximately 41mm), providing a medium level of comfort, suitable for smooth or slightly uneven roads.
    • 1⅜: The tire height (or cross-section shape) is 1⅜ inches (approximately 35mm).
  • French Sizes: 700×35C
    • 700: Refers to the 700C outer diameter, the standard size for most road bike wheels.
    • 35: The tire width is 35mm, offering a good balance between comfort and speed, ideal for urban commuting and light off-road riding.
    • C: Indicates that this tire is designed for a 700C rim.

Therefore, you need a 700C tire with a width of approximately 35-40mm, suitable for your wheels and riding needs.

Example 2: 40-622 (28×1.50 700×38C)

How to Choose the Right Wheel Size-1
  • ETRTO Standard: 40-622
    • 40: Represents a tire width of 40mm, suitable for those seeking more comfort or stronger grip, such as for commuting, hybrid riding, or light off-roading.
    • 622: Indicates the tire’s inner diameter of 622mm, which fits the 700C rim, compatible with most road, hybrid, and some city bike rims.
  • English Size: 28×1.50
    • 28: The outer diameter is 28 inches, compatible with the 700C rim standard.
    • 1.50: The tire width is 1.5 inches (approximately 38mm), offering a medium width that provides comfort and stability, ideal for smooth roads or light off-road conditions.
  • French Sizes: 700×38C
    • 700: Refers to the 700C outer diameter, fitting most road bike rims.
    • 38: The tire width is 38mm, suitable for daily riding, city commuting, and light off-road use, offering better grip and comfort.
    • C: Indicates that this tire is designed for a 700C rim.

This tire marking indicates that you need a tire for a 700C rim, with a width of approximately 38-40mm.

2. How to Choose the Right Wheel Size

When selecting the right wheel size, the first thing to consider is your riding needs and the type of terrain. Different tire widths are suited for different environments and requirements:

  • Narrow tires (e.g., 35-37mm): Ideal for high-speed riding on flat city roads. Narrow tires have lower rolling resistance and higher speeds, but they provide less comfort and grip.
  • Medium-width tires (e.g., 38-40mm): Suitable for everyday commuting and light off-road use. These tires provide a good balance of comfort and stability, performing well on both city streets and rural roads.
  • Wide tires (over 40mm): Best for off-road riding or those requiring more comfort. Wide tires provide better grip and cushioning, making them ideal for rough terrains or longer rides.

3. Compatibility and Fit

Ensure that the chosen tire size is compatible with your bike rims. Most road bikes use 700C rims, but compatibility may vary between different bike models. Check the clearance in your frame and fork to ensure there is enough space for the selected tire width, especially when using wider tires.

Related article:

Bicycle Tire Circumference Chart

A bicycle tire circumference chart provides circumference data for different tire sizes to help determine the proper tire and wheel combination. By referencing this chart, you can accurately calculate the actual circumference of the tire, which optimizes the riding experience and allows for proper adjustment of the bicycle’s odometer.

Tire SizeISO SizeCircumference (meters)Circumference (mm)
700 x 18C18-6222.072070
700 x 19C19-6222.082080
700 x 20C20-6222.0862086
700 x 23C23-6222.0962096
700 x 25C25-6222.1052105
700C Tubular2.132130
700 x 28C28-6222.1362136
700 x 30C30-6222.1462146
700 x 32C32-6222.1552155
700 x 35C35-6222.1682168
700 x 38C38-6222.182180
700 x 40C40-6222.22200
700 x 44C44-6222.2352235
700 x 45C45-6222.2422242
700 x 47C47-6222.2682268
650 x 20C20-5711.9381938
650 x 23C23-5711.9441944
650 x 35A37-5902.092090
650 x 38B40-5842.1052105
650 x 38A40-5902.1252125
12″ x 1.75″47-2030.935935
12″ x 1.95″54-2030.94940
14″ x 1.50″40-2541.021020
14″ x 1.75″47-2541.0551055
16″ x 1.50″40-3051.1851185
16″ x 1.75″47-3051.1951195
16″ x 2.00″54-3051.2451245
16″ x 1-1/8″28-3491.291290
16″ x 1-3/8″37-3491.31300
18″ x 1.50″40-3551.341340
18″ x 1.75″47-3551.351350
20″ x 1.25″32-4061.451450
20″ x 1.35″35-4061.461460
20″ x 1.50″40-4061.491490
20″ x 1.75″47-4061.5151515
20″ x 1.95″50-4061.5651565
20″ x 1-1/8″28-4511.5451545
20″ x 1-3/8″37-4511.6151615
22″ x 1-3/8″37-5011.771770
22″ x 1-1/2″40-5011.7851785
24″ x 3/4″ Tubular1.7851785
24″ x 1″25-5201.7531753
24″ x 1-1/8″28-5401.7951795
24″ x 1-1/4″32-5401.9051905
24″ x 1.75″47-5071.891890
24″ x 2.00″50-5071.9251925
24″ x 2.125″54-5071.9651965
26″ x 7/8″ Tubular1.921920
26″ x 1.25″32-5591.951950
26″ x 1.40″37-5592.0052005
26″ x 1.50″40-5592.012010
26″ x 1.75″47-5592.0232023
26″ x 1.95″50-5592.052050
26″ x 2.00″52-5592.0552055
26″ x 2.1″54-5592.0682068
26″ x 2.125″57-5592.072070
26″ x 2.35″58-5592.0832083
26″ x 3.00″75-5592.172170
26″ x 1-1.0″25-5591.9131913
26″ x 1″25-5711.9521952
26″ x 1-1/8″28-5901.971970
26″ x 1-3/8″37-5902.0682068
26″ x 1-1/2″37-5842.12100
27″ x 1″25-6302.1452145
27″ x 1-1/8″28-6302.1552155
27″ x 1-1/4″32-6302.1612161
27″ x 1-3/8″37-6302.1692169
27.5″ x 1.50″40-5842.0792079
27.5″ x 1.95″50-5842.092090
27.5″ x 2.10″54-5842.1482148
27.5″ x 2.25″57-5842.1822182
29″ x 2.25″58-6222.2812281
29″ x 2.1″54-6222.2882288
29″ x 2.2″56-6222.2982298
29″ x 2.3″60-6222.3262326

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