Nowadays, bicycles have a variety of wheel sizes to choose from, and if you explore folding bicycles, backrest bicycles and other professional bicycles, you will find more. Why are there so many choices? Why are there so many names for the same size? How do you know what is best for your riding style? This may seem like a daunting topic, but here we explain all the information about bicycle wheel sizes.

Let’s Start Small

16″ Wheels (ISO 305 mm)

Although they are most commonly found on children's bicycles, 16-inch wheels are usually the smallest bicycle wheels you see on adult bicycles. They are used in some adult folding bicycles to provide a compact folding size, but at the expense of riding quality. Although they are great for young people who are just learning to stay upright, 16-inch wheels do not perform well on bumpy or rough roads. The smaller the wheel, even small debris and rocks, it will be more affected, and the potholes can swallow the entire 16-inch wheel.

The handling and feel of a bicycle with 16-inch wheels will be very different from the full-size adult bicycle you are used to. The turning radius and wheelbase are small, which may cause the steering to be too sensitive. Smaller wheels also require larger gear ratios so that they can turn fast enough to keep up with other bicycles. This makes climbing a mountain more difficult.

20″ Wheels (ISO 406 mm)

20-inch wheels are the standard configuration of BMX bicycles and the most common size for "small wheels" folding bicycles. BMX riders choose them because of their mobility, making flat terrain and aerial skills easier, but for ordinary riders, they still have many of the shortcomings of small wheels mentioned above. Although slightly better than 16 inches, 20-inch wheels are still affected by rocks and obstacles compared to larger standard wheel sizes. Smaller wheels also require unique frame geometry and extra-long handlebars to provide the rider with a normal upright position. This will further exacerbate handling problems and allow unnecessary bending of the steering column and frame.

ISO 451-It should also be mentioned that there is a slightly larger wheel size, which is also commonly referred to as 20 inches. That is the ISO 451 rim. This size is used in some BMX racing cars and some classic British shopping bikes. ISO 451 wheels are very rare on modern bicycles, so in most cases, you can assume that 20-inch wheels are ISO 406.

24″ Wheels (ISO 507 mm)

A fairly rare size, 24-inch wheels are most commonly found on junior mountain bikes, and a few BMX "cruiser" models are designed for large riders who seek the same geometry and mobility as 20-inch counterparts. With more emphasis on youth racing than ever, and the increase in high-end specifications for children's mountain bikes, the category of 24-inch junior mountain bikes is growing.

Standard Full-Size Wheels

26″ Wheels (ISO 559 mm)

26-inch wheels have a long history in the bicycle industry. It started as the standard for American cruisers about 100 years ago, and later became the most popular mountain bike wheel size, and has maintained its leading position for decades. When pioneers such as Joe Breeze, Charlie Kelly, and Gary Fisher made the world's first mountain bike, the old 26-inch cruiser wheels were the only bicycle wheels with tires wide enough to meet off-road requirements. As the standard for mountain bikes, this size is used in many high-performance folding bikes, including Montague's Paratrooper series.

As with most bicycle wheel naming conventions, the term "26 inches" does not refer to the diameter of the wheel itself, but to the approximate outer diameter of a tire that fits that wheel size. The actual ISO diameter of a traditional 26-inch wheel is 559 mm.

27.5″ / 650b Wheels (ISO 584 mm)

As we all know, one thing that is confusing about bicycle wheel sizes is the use of different names for the same size. Wheels with an ISO diameter of 584 mm were originally called 650b and were first introduced on touring bicycles in France in the 1960s. Because they are slightly smaller than modern road bike wheels, they are still used on small and ultra-small road frames that cannot accommodate 700c wheels. When used on road bikes or gravel bikes, this size is still called 650b, but it has also been adopted and renamed by the mountain bike industry.

In recent years, mountain bikes have been moving to larger wheels. When the 650b was re-used for off-road use, it was called 27.5". Compared with the 26-inch wheels that dominate the MTB world, 27.5-inch wheels have many advantages, including The ability to easily climb over obstacles, a larger contact area to provide greater traction and greater moment of inertia to maintain power. Montague Paratrooper Highline and Paratrooper Elite both use 27.5 inch wheels and are the first in the world to do so Folding bicycle.

29″ / 700c (ISO 622 mm)

Here we have two more common wheel sizes, they are actually exactly the same! The ISO diameter of a standard modern road bike wheel is 622 mm, which is called 700c (makes sense, right?/s). The history of this name needs another blog post to fully explain it, but the short version is that it comes from the international tire size, the outer diameter is about 700 mm, multiple rim sizes will be marked as 700a, 700b, 700c, and the others have disappeared. But 622 mm rims have become the most common narrow road tires, and almost all adult bicycles used on sidewalks in the world are equipped with 700c wheels, including Montague's Pavement folding bicycle series. The use of this full-size wheel can provide excellent performance and ride quality for the small wheel folder.

Just as the 650b wheel set was adopted by mountain bikers and became 27.5 inches, the 700c wheel set has taken the mountain bike world by storm in recent years and is called 29 inches. All the advantages of the larger wheels mentioned above are pushed to the limit on a 29-inch (or 29er) mountain bike, although some riders feel that the sacrifice in mobility and turning radius is not worth it. Although the 29" and 700c wheels have the same diameter at 622 mm, the rims made for mountain bikes are usually wider to accommodate wider tires.

27″ (ISO 630mm)

The ISO 630mm size is basically no longer in use, but since a large number of American road bikes that used these "27-inch" wheels in the 1970s and 1980s are still roaming in basements and garages, it is worth including the country. The rim itself is slightly larger than the modern 700c wheels, and many of us learned this through painstaking methods after buying new road tires and working hard to secure them. Due to the large number of wheels in circulation, tire manufacturers still produce 27-inch tires, so if you need to buy new tires for that old steel race car, please order from your local bicycle shop.

Oversized

32″ (ISO 686 mm) and 36″ (ISO 787 mm)

Although very rare, frames customized for very tall riders usually use 32-inch or 36-inch wheels. These sizes are hardly found on mass-produced bicycles, but if you are more than 6 feet 6 inches tall and are looking for a suitable bicycle, customization may be the only way out. A quick search for "Shaq Bicycle", you will see various bicycles made by NBA legend Shaquille O'Neal over the years. Although the wheels may look directly proportional to the frame, they are all monster sizes of 32 inches and 36 inches.

Please contact us(sales1@gofastbicycle.com) to discuss and provide you with customized services.