Bike Wheel Sizes: The Ultimate Guide
Bicycles come in the form of all shapes and sizes, designed to fit the preferences and purposes of different riders. One of the most significant differences when looking into bike specifications is the wheel sizes.
Wheel sizes affect how the bike performs and handles; therefore, it’s essential to know how to choose the right wheel size for your bike. Bicycles are a hefty investment, so it’s imperative that you pick a wheel size that fits right and delivers a smooth, comfortable ride.
If you’re searching for replacement wheels or looking for a new bike but are unsure about which size wheels to get, you’ve come to the right place. This guide covers why bike wheel sizes are important and explain in detail the different wheel sizes and who they’re made for.
Let’s jump right in!
Why is Bike Wheel Size Important?
Bike wheel sizes are important for many reasons, considering they affect how the performance and feel of the ride. It plays a significant role in how the bike handles and feels when riding in various terrains.
For instance, speed is important in cyclocross and road riding, so it makes sense to have large 29-inch wheels. In mountain biking, 26-inch wheels are more agile and faster than 29ers, making them more conducive to steep and windy trails. However, the 29er is more comforter and maintains momentum easily, meaning it’s better suited for gravel biking and other rough terrains.
Typically, frames are made with a specific wheel size in mind, meaning altering how the bike moves and feels can hinder performance. Also, the wheel size is influenced by each person’s body shape and preferences, so make sure to test it out at a bike shop to get an idea of what wheel and bike geometry is best for you.
A bike with size-specific geometry may have smaller wheels on its smaller bikes and standard wheels on its average-sized bikes. However, this is different depending on the use case. For example, a gravel bike may have smaller wheels to fit a wider tire into the frame space.
The type of road you travel on affects the size of your wheels. Your terrain may require a smaller wheel with a wider tire if it is very bumpy. If your terrain is smooth, a larger wheel with a smaller tire may be more appropriate.
Wheel size depends on bike type and brake type. Rim brakes will limit the width of a tire you can fit within your bike, whereas disc brakes allow wider tires.
Different Bike Wheel Size Standards
Bicycle wheels are measured in several ways, which can lead to confusion. Ideally, bike wheels should be measured using a single unit of measurement, but unfortunately, the cycling world has made sizing measurement complicated.
There are several countries that have their own units of measurement for bicycle wheels. Therefore, it’s essential to understand the standard sizing systems so you won’t have trouble ordering new inner tubes or tires in the future.
Also, it’s important to note that the size of the wheel refers to the tire’s outer diameter. Below, we’ll discuss the various units of tire and wheel sizes.
International Organization for Standardization (ISO)
ISO is probably the most commonly used system for sizing wheels and tires. The European Tyre and Rim Technical Organization, or ETRTO, developed it. In ISO standards, the diameter of the wheel is measured in millimeters, not the tire’s dimensions.
The International Standardization Organization (ISO) created this to combine various international measurements together so that everyone can use a single measurement that can be used worldwide.
Consumers and manufacturers benefit from the ISO’s unification of measurements across all industries, not just cycling.
European Tyre And Rim Technical Organization (ETRTO)
The ETRTO system is used to distinguish between different-sized tires and rims. In order to simplify and make sense of the many wheels and tire sizes developed by different countries, ERTO was introduced to measure wheel circumference.
French Standard
French wheel size usage has declined gradually since ISO wheel sizes were introduced. These tires were labeled from A to D. A tires were narrow, and D tires were wide.
The French tire size system is still displayed on most wheels and tires. As an example, a large tire is usually indicated by the letter “C,” found on 700C road bike wheels.
American Standard
Inch-based notations are often used by big-box retailers for children’s bikes and mountain bikes. You might see 24” tires on a junior bike and 20” tires on a child’s bike.
Standard Adult Bike Wheel Sizes Explained
Bike wheel sizes come in many standard sizes, from 26 to 29 inches. These wheel sizes are typically found on mountain, gravel, touring, and road bikes. Here’s a table that illustrates the use cases for each wheel size so you know which size is right for your needs.
| Wheel Size | Height | Bike Types |
| 26-inch | >4’10” (149 cm) | Dirt jump, BMX |
| 27.5-inch | >5’5” (165 cm) | Hybrid, Touring, Mountain |
| 28-inch | > 5’6” (168 cm) | Old English Road and Track Bikes |
| 29-inch | >5’6” (168 cm) | Mountain |
26-inch Wheels
For many years, 26” wheels have been the standard bike wheel size. It was once the most popular mountain bike wheel size because of its strength, maneuverability, and quick acceleration.
The 26-inch wheels we see today are often found on hybrid bikes, off-road mountain bikes, and high-performance folding bikes, but they were originally used by road cruisers in the early 20th century. The wheels measure 559 mm, which is the ISO measurement.
Compared to 29-inch wheels, smaller wheels have a deeper angle of attack, which makes them less effective at moving over obstacles. Since smaller wheels require fewer spokes, they produce less turbulence and drag. In this way, 26-inch or 559mm wheels can accelerate and maneuver quickly with high top speeds.
A traditional 26” wheel has an ISO diameter of 559mm. While smaller wheels provide agile and fun handling, they don’t roll as fast as larger ones. As a result, 26-inch wheels are pretty much a thing of the past on mountain bikes.
27.5-inch Wheels
27-inch bike wheels are an in-between size that is commonly found on road bikes, mountain bikes, and occasionally hybrid bikes. For reference, a 27.5-inch bike wheel, also known as ISO 584, has a matching ISO size of 603mm.
In the beginning, 27.5′′ wheels were used on bicycle frames that were too small for 700c wheels, but they were adopted for use on mountain bikes as well. Some mountain bikers consider 27.5′′ wheels to be a good compromise between 26′′ and 29′′ wheels. In terms of mountain bike wheels, a 27.5-inch wheel offers the best balance between a lightweight design and a narrow angle of attack.
27.5-inch bike wheels have the weight of a larger wheel but are small enough to have high top speeds and fast acceleration without sacrificing their ability to handle trail obstacles. The larger contact patch of 27.5′′ wheels allows them to roll over bumps easier while having better traction and braking. Additionally, they provide agile handling while maintaining momentum.
28-inch Wheels
There are four traditional 28” bike wheel sizes: 700, 700A, 700B, and 700C. Bicycle wheels with a diameter of 28 inches were used on old English roads and track bikes and in several Asian and Middle Eastern countries (where they are still popular today).
The 28-inch bike wheels are commonly found on road bikes and mountain bikes today.
While 700 and 700A wheels are rare now, 700B wheels have an ISO of 635mm and are commonly used by gravel bikes and other off-road inclined bikes around the world.
Older Dutch, Chinese, English, and Indian rod-brake roadsters occasionally have 28-inch wheels that are 1 1/2 inches wide. 28-inch bike wheel’s BSD (bead seat diameter) is 622 mm. In the past, 28-inch wheels with a BSD of 647mm were popular, but they are no longer available.
29-inch Wheels
In the past, 29-inch or ISO 622 mm bike wheels were known as 700C, referring to their combination of a 700 mm outside diameter and an alternative rim size (adding up to 700 mm).
It is the standard full-size wheel on almost every adult road bike today. Additionally, it’s a popular choice for folding pavement bikes.
Compared to a 26-inch wheel, a 29-inch wheel offers 12% more static weight, so it’s more stable on the road.
Due to its relatively flat angle of attack, this size is excellent for rolling over obstacles, but the added drag limits acceleration and control, so it isn’t the best size for mountain biking.
A larger wheel gives you better ride quality and faster speed. As a result, mountain bike manufacturers have begun using it on their bikes with great success. However, its larger wheel size increases the bike’s turning radius and limits its maneuverability. Getting up to speed also takes a little more effort.
Mullet Bikes
Mullet mountain bikes are unique in that they incorporate a 29-inch wheel on the front and a 27.5-inch wheel on the back. The larger front wheel delivers enhanced stability and rollover, while the smaller rear wheel helps with sharp cornering and agility. Mullet bikes are commonly used for downhill riding.
Sometimes you may find other iterations of the mullet, such as a 27.5-inch front and 26-inch back or 29-inch front and 26-inch back wheel.
Oversized Bike Wheel Sizes
There are plus-size or oversized bikes for the tallest cyclists. Since these bikes are usually made to order, they’re considerably more expensive than regular bikes.
Aside from small sizes, nonstandard wheels also offer tailored fit for cyclists with specific needs. A large bike wheel offers a number of benefits, including
- A low angle of attack makes trail obstacles easier to handle
- A higher level of stability due to more ground contact and increased spokes
- Increased weight results in a consistent speed
The most common oversized wheel sizes are 32 and 36 inches.
| Wheel Size | Height |
| 32-inch | >6’6” |
| 36-inch | >6’6” |
32-inch Wheels
The demand for bicycles with wheels larger than 29 inches is so low that they’re almost always custom-built.
If you’re taller than 6’6”, you may need a larger bike than those found at most cycling stores. Taller riders typically ride bikes with 29-inch wheels, but if your budget allows it, you might consider a 32 or 36-inch bespoke bike.
As 32” bicycles are almost always custom-made, they’re much more expensive than bikes with standard wheels.
36-inch Wheels
Due to their massive attack angle, 36-inch wheels would be much more comfortable to ride than 29-inch wheels. Nonetheless, it’s hard to find a manufacturer that would make a 36” wheel for you, and a bike with 36” wheels would be heavy and sluggish in corners.
Kid’s and Adult Bike Wheel Sizes Explained
Most kids’ bikes have wheels between 12 inches and 20 inches, and the size of the wheels usually matches the size of the frame.
Unless the bike is custom or nonstandard, a 16-inch kid’s bike wheel comes on the same size bike frame. Here are guidelines to follow based on your child’s age and height to choose the right wheel size.
| Wheel Size | Age | Height | Use |
| 12-inch wheels | 2 to 4 years old | (86.8 to 102.3 cm) | Kid’s balance bike |
| 14 to 16-inch wheels | 5 to 6 years old | (109.2 to 115.5 cm) | Kids balance bike |
| 18 to 20-inch wheels | 7 to 9 years old | (121.9 to 128 cm) | Kids folding |
| 24-inch wheels | 10 to 11 years old | (138.4 to 143.5 cm) | Kids folding |
| 26-inch wheels | 12 years old | (149.1 cm) | Kids folding |
Adult cyclists can also use small wheel sizes. We recommend only using 16 inches and beyond for adults.
Smaller wheel sizes are great for travelers, BMX riders, and cyclists looking to gain every millisecond of speed advantage possible. Some of the advantages of using a small bike wheel size are:
- Faster accelerates because of the lightweight build
- Precise control from the boost in responsivity of a smaller wheel
- Higher top speed from less drag
- Great portability from low weight and small size
12-inch Wheels
12-inch bike wheels are commonly found on training bicycles for toddlers and young children. Most three-year-olds and some four-year-olds will enjoy these bikes.
The most effective way to find the correct kid’s bike size is to measure your child’s height and inseam length and compare that to the manufacturer’s recommended rider measurements. Typically, 12-inch wheels can be found on toddler’s bikes, kid’s balance bikes, and bikes with training wheels.
14-inch Wheels
A 14-inch kids’ bike wheel is designed for children between the ages of 5 and 6. Kids who are taller or bigger than average may also benefit from a 14-inch kids’ bike. These wheel sizes are commonly found in kid’s bikes, compact folding bikes, and mini e-bikes.
The small wheel size allows for a more compact folding design but has very sensitive steering due to the small turning radius. And it’s also uncomfortable on bumpy terrain.
As 14-inch bike wheels can vary slightly in size, you might come across several different ISO measurements when shopping for 14-inch wheels. The ISO of 14” wheels is 298mm, but other sizes are available, ranging from 254 to 298mm.
16-inch Wheels
16-inch wheels are most common on kid’s bikes, but they’re also the smallest on adult bikes. Some manufacturers will add 16-inch wheels on folding bikes to make them more compact.
Due to their small size, these wheels don’t roll well over bumps, which compromises ride quality. The bike has a tighter turning radius, but its steering becomes very sensitive. The bike with smaller wheels must have a higher gear ratio to keep up with the bike with larger wheels. As a result, riding uphill becomes more difficult.
For kids learning how to maneuver the bike and stay upright, 16-inch wheels are ideal. It’s suitable for most four- and five-year-olds to ride a bike with wheels of 16 inches. If your three-year-old is tall for their age, they may fit on a 16-inch bike.
Generally, 16-inch bike wheels (or ISO 305 mm) are found on children’s bikes, but they’re not all small bikes for kids. Most adult bikes with 16-inch wheels are compact folding bicycles. It can be appealing to some riders since it’s lightweight and easy to travel with, but it comes at the expense of ride quality.
With wheels this small, even the slightest obstacle on the road adversely affects them. In addition, their higher gear ratio makes it difficult for them to handle hills. Additionally, the steering can be oversensitive since the turning radius is so small, with a 305 mm wheel diameter. Oversensitivity is beneficial to BMX bikers looking to gain more control over their steering column but not ideal for casual riders.
20-inch Wheels
The most common bike size for six- and seven-year-olds is 20 inches. A five-year-old who is tall might also fit on this bike. It’s common to find 20-inch wheels on kids’ bikes, folding bikes, BMX bikes, and moped-style eBikes.
The 20-inch bike wheel can be an inconvenience for the normal rider looking to use a folding bike as their primary traveling road bike. Small-wheel bikes have a small turn radius, which causes handling issues due to their extra-long handlebar stems.
BMX bikers searching for an extra-sensitive steering column that supports aerial tricks will find this size ideal.
BMX bikes typically have 20-inch wheels, which make them maneuverable, which is essential for tricks. Their small size, however, means that they suffer from similar drawbacks, but to a lesser extent than 16-inch wheels. 20-inch wheels are more prone to obstacles and bumps compared to larger wheels.
24-inch Wheels
24-inch wheels are quite rare on bikes, but they do exist. If you find them, they’ll be on BMX cruisers or junior mountain bikes. However, the popularity of mountain biking and BMX has prompted a demand for nonstandard wheel sizes for these frame types.
For larger riders, BMX cruisers are better than 20-inch wheeled bikes because they have similar geometry figures and maneuverability. Youth mountain bikes with 24′′ wheels typically have higher specifications than those with smaller wheels, making them ideal for racers.
It is at this size where the line between kid and adult bike sizes starts to blur as many children approach the size of an adult bike. Typically, children aged eight to ten do well on a 24-inch bike, but adults under five feet may also benefit. In ISO terms, a 24-inch bike wheel measures 507 millimeters.
How to Measure Bike Wheel Size
While the size of a bike wheel is often printed on the tire, it’s still worth learning how to measure a bike wheel size. Perhaps, you may be inheriting a bike or want to buy a secondhand bike, so understanding how to measure a bike’s wheel size comes in handy. Once you know the size of your wheel size, you can test it out and see whether the bike wheel should be replaced so that you can find an option tailored to your needs.
Measuring Wheel Size Using the Standard Method
Place your bike against a wall or on a bike stand. This will allow you to accurately measure the wheels of your bike without falling over. Measure the distance from the ground to the axle of the wheel in inches. You will then have the wheel’s radius, which is half its diameter. Using a retractable tape measure will free up your hands. For the diameter of the wheel, multiply your measurement by 2.
Now that you know the diameter of the wheel, you need to determine its width. The easiest way to measure the tire is to run a tape measure across it.
Measuring Wheel Size Using the ISO Method
A bike’s wheel size is measured in millimeters according to the ISO system. This method provides a more accurate measurement since the increments are smaller.
When you are measuring your bike, prop it against a wall or make sure it is secure enough not to fall on you. You can use the same method as before but measure in millimeters instead of inches. Rather than measuring from the axle to the ground, measure from the axle to the tire’s inner edge. Once you have the measurement, multiply it by 2 to get the diameter.
Frequently Asked Questions?
Here are commonly asked questions about bike wheel sizes:
What is the most common wheel size?
Road bikes typically have 700c wheels. Mountain bike tires are typically 29 or 27.5 inches in size.
What size tire does a hybrid bike use?
The most common hybrid bike wheel size is 700c with a knobby tire for extra grip. However, some hybrid bikes have tires as small as 26 inches.
How can I find my bike’s wheel size?
There are a few places where you can find out your bike’s wheel size. The first place to look is on the rim itself. However, if it’s not there, there may be a sticker on the bike’s frame. Consider checking the manufacturer’s website and looking in the user manual or under tech specs.
How should you choose your bike wheel size?
You should choose your size range based on your riding style, not the other way around. Bikes like BMXs and mountain bikes don’t even fall into the same category. Most road cyclists prefer 25 mm rim widths, which offer a balance between performance and stability. A smaller rim width, usually 23 mm, can provide improved acceleration and top speed for racing cyclists.
Off-road cyclists are advised to consider wider rims for added stability, typically 28 mm wide.
You can determine the size of a wheel by measuring the distance between the axle assembly and the outer rim. When in doubt about tire and rim sizing for your body size and preferred style, see a bicycle specialist in person.
Does Bike Wheel Size Include Tire?
There are some bicycle wheel measurements that include tire height, while others don’t.
Wheels and tires with a diameter of 700mm are measured as “700c.”. A “622” on a bike wheel refers to the bead seat diameter. The bead seat of a bike wheel is located inside the rim, so the wheel size 622 refers to the rim.
When should you use 650b wheels?
650b wheels are a little smaller than 700c wheels. Typically, they serve two purposes. A 650b wheel might be found on a very small road bike. Gravel bikes usually have 650b wheels with wide, grippy tires. As a result, a wide tire can be mounted on the bike with this configuration.
What Size is a Bike Wheel Nut?
A 15mm wrench is required to adjust bike wheel nuts (for attaching your wheel to your frame), which are normally 15mm wide (0.6′′).
Wrapping It Up
Learning the ins and outs of different bike wheel sizes gives you a baseline knowledge of how wheels work and the advantage that the right size can have. There are many wheel sizes; some are standard, while others aren’t.
Depending on your height, age and purpose, it’s important to ensure your wheel size, frame, and type of bike riding aligns with your needs.
Now you can take this knowledge and find the right bike suitable for your biking adventures!
