What wheel sizes are there?
There isn’t a single wheel size; bikes use a range of wheel diameters from about 12 inches for toddlers to 29 inches for many trail and road bikes, with several standard sizes in between.
Bicycle wheel sizes: a quick guide
Wheels on bicycles are categorized primarily by diameter, which affects ride feel, stability, and compatibility with frames and brakes. The following sizes cover the vast majority of bikes you’ll encounter, from kids’ bikes to adult mountain and road bikes.
- 12 inches: Used on very young children’s bikes and balance bikes; small, low to the ground for easy mounting and learning balance.
- 14 inches: For early childhood bikes; still aimed at beginners with small frames and wheels.
- 16 inches: Common on kids’ bikes for ages roughly 4–6; provides more stability as kids learn to pedal and steer.
- 18 inches: Another kids’ size found on some youth models; typically for children around 5–7 years old.
- 20 inches: Popular on BMX bikes and many youth bikes; compact for tricks and tight turns.
- 24 inches: Found on some youth models and small adults’ bikes; a stepping stone toward larger wheels.
- 26 inches: The traditional mountain bike size; offers good stability and a broad selection of components, though less common on new models compared with newer standards.
- 27.5 inches (650B): A modern MTB standard that balances quick acceleration with good rollover capability; widely used on trail bikes and many cross-country setups.
- 29 inches (often labeled as 29er or 700c in some contexts): Large-diameter wheel that rolls over obstacles well and maintains momentum; common on cross-country and many gravel bikes.
- 27.5+ and 29+ sizes: Plus-width tires (roughly 2.8"–3.25" on 27.5" wheels or 3"–3.5" on 29" wheels) for extra traction and cushion, popular on certain trail and fat-adjacent bikes.
- 26" fat tires: 26" wheels with very wide tires (roughly 3.8"–4.8") used on fat bikes for improved floatation in sand, snow, or mud.
Note that wheel size terminology can vary by brand and region, and some bikes use older or less common sizes like 650c for smaller frames. Always verify compatibility with frame clearance, brakes, and tire choices when upgrading.
What marks wheel size and how to read it
Wheel size is typically described in two ways: the overall diameter of the wheel including the tire (for example, 29" or 26"), or the bead-seat diameter (BSD) with tire width (for example, 622x25c for many road bikes). In practice, 29" and 700c share the same bead-seat diameter (about 622 mm), while the actual tire width varies widely. For kids’ bikes, sizes are often given by the approximate tire diameter (e.g., 16x2.0). When upgrading, check frame clearance and brake compatibility (rim brakes vs disc brakes) as a larger wheel can affect both fit and braking performance.
Other factors that matter
Beyond diameter, several other aspects influence ride quality and compatibility. Here are key considerations to keep in mind when choosing wheels:
- Rim width: Wider rims support wider tires and can improve stability and sidewall support.
- Tire width: Wider tires on wider rims offer more traction and comfort, especially on rough terrain.
- Brake compatibility: Rim brakes rely on a braking surface on the rim, while disc brakes require a rotor and caliper mounting that may factor into wheel compatibility.
Understanding these details helps riders select wheels that match their riding goals, whether it’s speed on pavement, stability on trails, or comfort in mixed terrain.
Summary
The world of bicycle wheel sizes spans from tiny 12-inch wheels for toddlers to large 29-inch wheels for adults, with a spectrum of sizes in between. Modern trends emphasize 27.5" (650B), 29" (700c), and plus-width configurations, while traditional 26" remains in use on many older bikes and some builds. When selecting wheels, consider rider size, intended terrain, frame and brake compatibility, and tire width to find the right balance of acceleration, stability, and comfort.
What are the different wheel sizes?
Wheel diameters can vary, but they typically range from 13"-24" (or higher for specialized low profile fitments). Only wheels and tires of the same diameter can be safely mounted together, meaning you can only mount a 16" tire on a 16" wheel.
What does 4.80 4.00 8 mean on a tire?
The numbers 4.80/4.00-8 read like this: 4.80" is the tire width, 4.00" is the tire section height (from the inside of the donut hole to the outside) and the 8" is the wheel diameter.
Is a 275 tire the same as a 33?
No, a "275 tire" is not the same as a "33-inch tire" because the numbers represent different measurements in a tire's size. However, a specific metric size, such as a 275/60R20, can be nearly equivalent to a 33-inch diameter tire. The term "33" is a common, non-metric measurement for a tire's approximate overall diameter.
Tire size explained
- Metric size (e.g., 275/60R20): This is a precise measurement with three parts:
- 275: The width of the tire in millimeters.
- 60: The aspect ratio, which is the height of the sidewall as a percentage of the width (60% of 275mm).
- R20: The radial construction and the diameter of the wheel in inches.
- Non-metric size (e.g., 33x12.5R20): This is a common, more direct way to refer to a tire's approximate overall diameter:
- 33: The approximate total height of the tire in inches.
- 12.5: The width of the tire in inches.
- R20: The radial construction and the diameter of the wheel in inches.
When they are similar
- A 275/60R20 tire is a close equivalent to a 33-inch tire, with a total diameter of approximately 33 inches.
- Other metric sizes, like a 285/75R16, also result in a diameter close to 33 inches.
Why it matters
- Compatibility: Always check the exact metric size of a tire to ensure it will fit your vehicle and is compatible with your suspension and wheel size.
- Speedometer accuracy: Changing your tire diameter significantly can cause your speedometer to be inaccurate. For example, larger tires will make you appear to be driving faster than you actually are.
What are the 4 types of wheels?
The four main categories of wheels include steel, alloy, forged, and chrome. Each type offers distinct advantages and considerations for different driving needs. Alloy wheels, primarily made from aluminum, dominate the modern car wheel market due to their balance of performance and style.
