Which Mountain Bike Wheel Size Is Right for You?

Biking a scenic trail. Mountain biking

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While 26-inch wheels are still considered the “standard” for mountain bikes, 29-inch wheels are fast on their heels. And right behind those big 29ers are wheels of yet another size. Sometimes referred to as 650B, the 27.5-inch wheel fits right in between the 26- and 29-inch offerings. So which wheel size is right for you? Consider the following pros and cons of each, and decide which size to test-drive first. After all, the best way to test a bike technology is to take it for a ride.

26-Inch Wheels

Long considered the standard wheel size in the mountain bike industry, 26 inches is likely the size of the wheels you have on your mountain bike now, unless you actively sought out something different.

The advantages: 26-inch wheels offer unmatched maneuverability. Why? Because virtually all advancements in mountain bike geometry and technology have been modeled off of 26-inch wheels. The 26-inch-wheel bike has been evolving for many, many years and because of that, its front-center/rear-center balance is ideal. It also offers a slightly shorter wheelbase and has a lower center of gravity than bikes with larger wheels, making it nimbler in tight turns. Smaller wheels also accelerate more quickly because the wheel's rotational mass--basically the weight of the wheel--is closer to the hub. 

The disadvantages: The speedy acceleration of small wheels has a flip side: greater rolling resistance. That means they don't roll as efficiently or maintain momentum as well as larger wheel once you're up to speed. Smaller wheels have a harder time going over obstacles. They also don't have as much contact with the ground, which means less traction. Some cyclists believe that larger wheels represent an evolutionary change in cycling. Mountain bikes started out with 26-inch wheels because that's what most full-size bikes had in those days. But as mountain biking has matured over the years, it might be looking to larger wheels as a better mousetrap.

29-Inch Wheels

Gaining major momentum, 29-inch-wheels are expected to become the prevailing wheel size for most mountain bikes with 5 inches of travel or less.

The advantages: Bikes with 29-inch wheels—commonly called “29ers”—can ride over anything. OK, maybe not everything, but it sure feels like it! I’ve marveled in disbelief after riding over logs and other obstacles that slow me down or stop me in my tracks on my 26-inch steed. Wondering how? The obstacle hits the rim of the 29er at a lower point, making it easier to roll up and over. Other advantages include maintained momentum, reduced rolling resistance and increased stability from a longer wheelbase.

The disadvantages: Regrettably, that longer wheelbase also reduces the bike’s maneuverability. The chainstays on 29er need to be longer in order to fit a larger wheel on the frame. Longer chainstays result in not-so-ideal handling. Then there's the two-sided issue of greater rotational mass: larger wheels accelerate slower but maintain speed better. 

27.5-Inch Wheels

Around for a long while, but largely ignored, the middle child of mountain bike wheels has people talking these days. As a wider selection of 27.5-specific components become available, the mountain biking industry—and the mountain bikers themselves—are taking notice.

The advantages: Advocates of 27.5-inch wheels—sometimes called 650B—state that they offer the same roll-over qualities as 29ers, without compromising maneuverability. They also allow shorter riders who might not feel comfortable on 29-inch wheels the chance to experience a bigger-sized wheel. What’s more, you can have longer travel than a 29er without compromising geometry.

The disadvantages: At the moment, there is a limited selection of tires, wheels, and forks to pick from. In addition, some industry insiders don’t see 27.5-inch wheels offering a big enough performance benefit over 29-inch wheels to justify their rise in popularity.

The Bottom Line

So, what wheel size is best for you: 26-inch, 27.5-inch or 29-inch? To answer that question, you must take into consideration who you are as a rider, what terrain you ride on most often and what you want out of your bike. Another factor that might be a deal clincher or breaker is size: bikes with smaller wheels typically have a shorter standover height; larger wheels are a bit taller. If you're on the short side, you might feel more comfortable on a 26-inch machine. If you're tall or long-legged, a 29er might be just what you've been waiting for. Again, the right bike is all about feel. Give all three sizes some test rides and the answer will roll right over you.

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