Wheel size plays a massive role in how a bike feels and handles when riding in different environments.
For example, speed is critical in road riding and cyclocross, so it only makes sense to use large 700c wheels. In mountain biking, a 26″ wheel mountain bike is more agile and faster off the mark than a 29er.
However, the 29er is faster, more comfortable, and maintains momentum easier, giving each MTB wheel size suitable to different disciplines.
26″ vs 27.5″ vs 29″ Mountain Bike Wheel Comparison
In general, frames are designed for one specific wheel size, meaning a different wheel alters how a bike feels and moves and may hinder performance. In addition, smaller wheels work best for smaller adults and children.
For this reason, many manufacturers change the wheel size to align with the frame size. For example, XS and S MTB frames mostly have 27.5″ wheels, whereas M+ will have 29″.
*Age recommendations based on Prevelo Bikes
Bike Size Wheel Chart (Diameter)
|inch (“)||mm||cm||Age / Height||Bike Types|
|12″||305mm||30.5cm||1½ +||Kids’ balance bikes|
|14″||355mm||35.5cm||2-5years||Kids’, kids’ balance bikes|
|20″||508mm||50.8cm||5-9years||Kids’, E-Folding, Folding, BMX|
|26″||660mm||66.0cm||12years+||Kids’, city, cruiser, dirt jump, BMX|
|27.5″||584mm||58.4cm||From 5’4″||Hybrid, Touring, Mountain|
|650b||584mm||58.4cm||All adults||Touring, hybrid, city|
|700c||622mm||62.2cm||from 4’10”||Road, fixie|
Finally, each person’s body shape and preferences play a significant role in the choice of wheel size, so the best way to understand which wheel and bike geometry are best for you is to go for a test ride at your local bike shop or even rent a bike for a day to get a good feel for it.
When choosing the right size for you or your child, use the chart above to identify the wheel size that corresponds to your age and height. However, keep in mind that the wheel size also depends on the size of the tire and tire pressure.
For example, a 26″ x 4″ fat tire has roughly the same diameter as a 29″ mountain bike tire.
Below, we’ve described each wheel’s strengths, weaknesses, and applications in more detail.
12-inch wheels are the smallest you can find. You find these on most kids’ training bikes (or electric balance bikes).
The best way to find the correct kids’ bike is to measure your child’s inseam length and height and compare that to the manufacturer’s recommended rider measurements.
- Kids’ balance bikes
- Bikes with training wheels
- Toddlers’ bikes (1.5-3y/o)
14-inch wheels are another size for young children ages 2 to 5. These are found on learners’ bikes like the 12″ wheels above and kids’ electric bikes.
- Kids’ bikes
- Balance bikes
- Kids’ electric bikes
16-inch wheel bikes are the smallest wheel size found on adults’ bikes, including electric mini-bikes and folding bikes.
This small wheel allows for a compact folding design but is uncomfortable on bumpy terrain, slow, and has very sensitive steering because of the small turning radius.
For childrens’ bikes, most kids ages 4 to 6 will fit a 16″ bike.
- Kids’ bikes (4-6)
- Mini eBikes
- Compact folding bikes (Brompton)
20-inch wheel bikes are one of the most common small sizes. These wheels are ideal for kids ages 5 to 9.
In addition, they are the most common wheel size for BMX bikes, folding and electric folding bikes. Some niche bike styles like moped-style e-bikes even use this size.
The issues with 20-inch wheels are similar to the 16″ described above. They are uncomfortable and difficult to handle but they are very strong for landing jumps and compact for folding.
- Kids’ bikes (5-9)
- Folding bikes
- Moped-style eBikes
- Folding electric bikes
- BMX bikes
Regular 24-inch wheel bikes are great for kids ages 7+ or even some petite adults (under 5′). Additionally, this size is typical on kids’ mountain bikes for those under 12.
These wheels offer comfort, speed, and rollover gains on the smaller 20″ size, making them much more enjoyable to ride.
- Older kids’ bikes (7+)
- Jr. mountain bikes
26-inch wheel bikes are easy to find nowadays with the growing popularity of fat biking. Firstly, it is the best size for kids ages 12 and over and many junior mountain bikes.
This bike was the first wheel size used in mountain biking, where enthusiasts turned old cruisers into Klunker bikes in California. The wheel was ubiquitous for a long time until 29,” and 27.5″ wheels took over.
Adult fat tire electric bikes, regular fat bikes, dirt jump bikes, slopestyle bikes, and cheap rigid mountain bikes still use these wheels.
They have a few key benefits for adults bikes:
- Fast acceleration on smooth terrain
The downsides for adults bikes are they’re slow, the poor rollover ability, and unstable.
- City bikes
- Cruiser bikes
- Fat bikes
- Dirt jump bikes
- Youth’s bikes (12+)
27.5″ / 650b (584mm) Wheels
In general, the measurement ‘27.5-inch’ is used to describe mountain bike wheels, and ‘650b’ represents non-mountain bike wheels, including hybrids, city bikes, and some gravel bikes.
This wheel is more suitable for wider tires than the 29″ or 700c wheel, making it great for some styles of mountain biking, wide urban tires, and for shorter riders who find 29″/700c wheels challenging to maneuver.
For mountain biking, the 27.5 offers a great middle-ground between the 26″ and 29er, improving maneuverability, strength, and acceleration over 29ers but sacrificing speed, rollover ability, and traction.
What’s the difference between 27.5″ and 650b wheels?
- 27.5″ wheels come with wider tires as standard
- Some 27.5″ tires may be too wide for 650b wheels
- They are the same diameter
- Hybrid and gravel use 650b
- Mountain bikes use 27.5″
The 28″ wheel is one of the least common on modern bikes. The actual ISO measurement for a 28″ wheel could be 622mm, like the 29″ and 700c, or 635mm.
The differentiating factor is the width of the rim and the tires it supports, roughly between a road-size 700c rim and a MTB 29er.
The one style of bike that still holds on to this wheel size is the European city bike or Dutch-style city bike, the most famous of which is a Dutch brand called Gazelle, which uses 28″ on almost all of their bikes.
- City bikes
- Dutch-style bikes
- Urban e-bikes
The 700c rim (622mm) is universal on road bikes and any bike made for speed on tarmac and asphalt.
These wheels are mostly found with tires between 23mm and 47mm, with anything wider requiring a 29″ wheel. Although the diameter on these two sizes is equal, the 29″ rim is wider, allowing for wider tires.
The tires’ width, tread depth, and rim size results in super-fast rolling speeds on smooth surfaces, making these rims perfect for racing. However, a slight disadvantage of the 700c is the lower maneuverability and acceleration compared to smaller rims.
An advantage of the popularity of these wheels is they are straightforward to replace or find new spokes in any bike shop.
- Road bikes
- Hybrid bikes
- Gravel bikes
- Fitness bikes
- Fixed-speed bikes
29-inch wheels are the most common mountain bike wheel size, based on the same diameter as the 700c, only slightly wider.
This size was the first to successfully replace 26″ MTB rims and quickly became famous for its speed, rollover ability (low attack angle), stability, and comfort.
The main issues with 29ers are:
- Low acceleration
- Poorer maneuverability (making them not ideal for technical downhill riding)
- Incompatibility with small bike frames and small riders (it’s common to see MTB manufacturers change the wheel size based on the frame size)
The characteristics of this wheel are best for cross-country, enduro, and trail mountain biking. In addition, they are great for beginner mountain bikers.
- Mountain bikes – XC, enduro, trail, and some downhill
Mullet mountain bikes are mixed-wheel bikes where the front rim has a larger diameter than the rear.
This creative mix theoretically provides the best of both 27.5″ wheels and 29ers, meaning improved rollover and stability of the larger front rim, paired with the agility and sharp cornering of the smaller rear rim.
For example, a modern version of this is the 27.5″ rear wheel and a 29″ front. Other iterations of the mullet included:
- 26″ with a 27.5″
- ’69er’ which is 26″ with a 29″
- 24″ with a 26″ which was the first pair that was tried
Mulleted bikes are primarily for downhill disciplines.
How to Measure a Bike Wheel Size?
Let’s assume you have checked your rim for the manufacturer’s printing of the size, and there was nothing to find.
If that’s the case, you can measure your wheels easily using the international standard (ISO). First, remove the wheel. Then measure from the center of the wheel hub to the rim’s outside edge and double the measurement to get the total diameter
If your instrument is in inches, covert it to cm or mm (1 inch = 2.54cm) and compare it to our chart at the beginning of the article to determine your wheel size.
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