The various different styles of mountain bikes also come with different wheel sizes. The choices can be confusing. So here is our guide to help you make a smart choice:
26 Inch: for most of the history of mountain biking, the standard wheel size was 26 inches. That has changed dramatically over the past decade. First, the 29er came along, which drove a fierce debate, but it caused each side to realize there was probably a compromise that made for a better outcome for all aspects of mountain biking. That led to the 27.5 inch wheel bike.
In regards to performance, 26 inch tires are great for maneuverability. Cornering, riding on narrow trails and ledges is enhanced. They also have less material so they are lighter and excel when you need to hike-a-bike. The compromise is that they do not roll over rocks and rough terrain like their bigger cousins. And for a beginner, with less skill, THAT’S A BIG PROBLEM.
29ers: These bikes just crush everything in their path. Speaking personally, the switch from a 26er to a 29er completely changed my riding and confidence. I used to panic with bigger loose rocks and rutted terrain, now I have confidence to just plow over obstacles. But I will admit, I have never been a skilled technical rider and my bike handling/maneuvering skills are way below where they should be for the amount of time I have spent mountain biking. This is precisely why 29ers are GREAT beginner bikes. But know this, the nature of riding 29ers will probably hold you back from being the best technical rider you can be. They are a crutch (which I love).
And I am also part of the cross-country crowd, which love the 29er.
27.5 Inch (650b): The 27.5 gives you the best of both of worlds. They roll easily over varied terrain and are more maneuverable. 27.5 inch wheels can be found on both full-suspension and hardtail bikes. This is probably your best choice if you have the budget. Getting comfortable and used to a 29er may make it hard to ever progress to a more versatile bike set-up so perhaps it's better to start with a 27.5.
24 Inch.: Kids’ mountain bikes. Most of these bikes are a less-expensive versions of adult bikes with lower range of components.
Now to decide whether to go tubeless or not? Learn more about converting to tubeless.