Whether you’re after a fast-rolling bike for barreling over everything or a quick and nimble ride for the tightest turns, there’s a bike — and wheel — for everyone. We’ve been rolling out MTB wheels and tech for decades, leading the industry’s progression to 29ers (bikes with 29˝ wheels), Smart Wheel Sizing, and more. Here, we’ll get you up to speed on some of the tech and help you find the best MTB wheel size for how and where you ride.

How are MTB wheel sizes measured?
Mountain bike wheels typically come in three sizes — 29˝, 27.5˝, and 26˝. These widely-used measurements refer to the outer diameter of the tire when mounted on a wheel’s rim.

29ers
Since 2002, we’ve been committed to the tech and progression of 29˝ wheels. The why is easy — 29ers are more stable, providing increased confidence, they give you more rubber on the ground for more traction, have more momentum for holding speed, and lower rolling resistance for tackling obstacles. They’re the perfect choice for mountain bikers of all abilities, from cross-country to trail and enduro.

Smart Wheel Sizing
While we favor 29ers for most riders, not all riders are the same size, and their wheels shouldn’t have to be, too. On select models, we offer Smart Wheel Sizing, scaling the wheel size with the size of the bike frame. This allows shorter riders to have more standover clearance and more nimble handling while taller riders have height-appropriate wheels and geometry. 

What about MX?
The term MX, sometimes called mullet, means a bike rolls with mixed wheel sizes, usually a 29˝ front wheel and a 27.5˝ rear wheel. Why have one of each? Riders hitting bigger, steeper terrain often want the obstacle-crushing benefits of a 29er but crave more nimble handling and tire clearance in the back. MX wheels offer the best of both worlds and are great for enduro riders and those on longer-travel bikes. 

Are 26˝ and 27.5˝ wheels still around?
Traditionally, 26˝ wheels were the norm for mountain bikes, but these days, they’re reserved for dirt jumpers, slopestyle bikes, and kids’ bikes. They’re incredibly nimble and playful, perfect for throwing tricks, but they aren’t as smooth-rolling or stable as larger, 29” wheels. We still use 27.5˝ wheels on smaller sized frames with Smart Wheel Sizing, and as rear wheels in MX setups.

What about mountain bike tire sizing?
When looking for MTB tires, sizes are written out with the tire’s outer diameter first, followed by its width in inches, like 29x2.4˝, 27.5x2.5˝. Wider tires with knobbier traction are ideal for trail and enduro riding where terrain is looser and rowdier, while narrower tire sizes are lighter and faster-rolling — perfect for XC. 

Before choosing a new tire size, be sure to check your bike’s listed tire clearance, which can be found in the service manual or online. Choosing a tire that is too large for your frame, even if it looks like it fits, can result in serious frame damage when mud and debris come into play — but this can easily be avoided with a quick spec check!