What is a 29er mountain bike: Everything you need to know before choosing one 

29-inch wheels have become the most popular wheelsize for mountain bikes in recent years. For a long time, 26-inch was the standard size for mountain bike wheels, and the change to this larger wheelsize makes a big difference to how a bike will feel. If you are unsure what a bigger wheel might mean for you and your riding, this guide will explain where they came from, what the benefits are and whether 29er wheels could be right for you.

Quite simply, a 29er mountain bike is any mountain bike equipped with 29-inch wheels on both the front and rear. Unlike road bikes and gravel bikes, which all come with a single wheelsize, there are several different wheelsize options within mountain biking. The size of your wheels has a big effect on how your bike will handle, how it rolls over obstacles and how it climbs, so getting the right wheelsize for your preferred style of riding can help you have more fun out on the trail.  

What do 28-inch, 700C, 622 ETRTO and 29-inch wheels have in common? They are all the same size. Confusing, isn’t it? This is because the history of larger wheels goes back almost as far as cycling itself. In fact, as early as 1886, the US Army’s 25th Infantry Corps Buffalo Soldiers were testing 28-inch-wheeled bikes for use in combat. As the mountain bike began to take shape in the 1970s, the early pioneers talked at length about using larger wheels, but struggled to get suitable tyres to ride off-road. Good, sturdy tyres were available in 26-inch casings, so that became the default size. It took until 1998 when WTB produced the first 700C prototypes of their Nano Raptor tyre that frame builders had a tyre worth building a bike around. 

With a good tyre to work with, 29er bikes began to emerge, with Willits showing a full-suspension 29-inch mountain bike at Interbike in 1999. Big-wheeled bikes emerged into the mainstream in 2002 as Gary Fisher produced the first mass-produced mountain bikes with larger wheels. They called them 29ers, and the name has stuck for mountain bikes ever since.

Although they were popular with the sport’s pioneers, big wheels took more than a decade to reach the mainstream. While 26-inch mountain bikes were developing into mountain-shredding monsters with long travel and aggressive geometry, 29ers were mainly confined to niche worlds within trail and cross-country riding. It was not until the mid-2010s that designers figured out how to translate this progress from 26-inch-wheeled bikes to 29ers. Once they crossed over, there was no stopping them and soon they made their way up to World Cup downhill, the pinnacle of technical riding. Today, it is the most popular wheelsize in mountain biking, with most bikes sold having at least one 29-inch wheel.

29-inch wheels became so popular because they bring a number of benefits compared to smaller wheels. The most immediately apparent is how they roll. Larger wheels take a little more effort to get up to speed, but once they are there, they roll more efficiently and faster than a smaller wheel. Larger tyres have a bigger contact patch with the ground, which means that 29er wheels offer more grip, which is helpful going up and down the hill. They also roll over obstacles more easily — a bigger wheel can roll over bigger obstacles more easily than a smaller wheel.

Depending on what kind of rider you are and how tall you are, there can be a few drawbacks to riding a mountain bike with 29-inch wheels.

Bike fit is one of the most important issues; smaller riders may find that a 29-inch wheel is big and unwieldy out on the trail. But, the final decision of whether a bigger wheel is right for you may come down to your level of riding experience, rather than your stature.  

For our Neuron range of bikes, we offer the two smallest sizes - S and XS - with 27.5-inch wheels, while the larger sizes come with 29-inch wheels. This is because the Neuron is designed to be an easy-to-ride bike. For riders up to 1.77 m tall who fit our small sizes, we think they will find 27.5-inch wheels more enjoyable, as they are less cumbersome. For our cross-country race weapon, the Lux, we only make them with 29-inch wheels. This is because 29-inch wheels are proven to roll faster, and we know that racers will always accept the challenge of a bigger wheel if it means more speed.  

If bike handling is the most important part of your decision, then whether 29-inch wheels are a good thing can become a very personal question. A 29-inch wheel will be slightly harder to turn than a smaller wheel, and the extra grip might actually be a negative in some situations. This is why we created our Spectral trail bike with the option to switch between 29 and 27.5-inch rear wheels, so riders can choose the setup that best suits them.  

In the early days of 29er mountain bikes, it was believed that 29ers needed different geometry than smaller-wheeled bikes. These days, that no longer the case, and it is the type of riding the bike is designed for that decides the geometry, not the wheelsize. The two measurements that do still change are the bottom bracket height and the chainstay. The bottom bracket drop, which measures the height of the bottom bracket in relation to the bike’s axles, is often greater than on a 26 or 27.5-inch bike to keep the crank at the same height in relation to the ground. The chainstay may also need to be longer to accommodate the larger wheel.

Maybe the best way to figure out whether a 29-inch mountain bike is right for you is to think about the type of riding you plan to do: 

When looking for your first mountain bike, the most important thing is overall bike fit, not wheelsize. We would recommend looking for a bike that fits your body, your budget and the riding you hope to do, rather than worrying about what size wheels it has. On some of our beginner-focused bikes, like the Grand Canyon, we offer the smaller sizes with 27.5-inch wheels because we think they are easier to handle for smaller riders, but the larger sizes all come with 29-inch wheels – the wheelsize is all about bike fit, not performance.  

For any riding where covering distance fast is a priority, a 29er will always be the top choice. The extra rolling speed and climbing grip of a bigger wheel is a must-have. Our Exceed speed hardtail is the perfect example of this. Whether you are using it for cross-country racing or gravel adventures, the benefits of a 29-inch wheel are undeniable for riders of all sizes.  

This is where the question of wheelsize gets tricky. There are no right or wrong answers for trail riding; the only thing that matters is what you enjoy. If you are the kind of rider who loves to do big loops and explore, maybe a 29er would suit you better. If you like to shred the descents, then maybe a mullet setup with a 29-inch front wheel and a 27.5-inch rear wheel would be more fun for you. (If you’re curious to learn more, check out our guide explaining what a mullet bike is and whether it’s a good choice for mountain biking). This is why we built our Spectral platform to accommodate both types of setup with a simple flip chip. 

It may seem counterintuitive in a sport that is raced against the clock on downhill stages, but we believe 29-inch wheels are the best choice for enduro. While there may be an advantage to having smaller wheels in the steepest, gnarliest sections of a race, that does not account for the rest of the day, which will likely include long climbs and stages with pedally sections. Over this kind of varied day of riding, our elite riders found that 29-inch wheels were the fastest, and this is why our Strive enduro bike is full 29.  

For a while, it was believed that taller riders would be better suited to a full 29-inch setup for downhill, while smaller riders should run a mullet setup with a 27.5-inch rear wheel. Testing with our CLLCTV factory downhill team proved this wrong, and we found that a mullet setup was the best choice for World Cup DH racing for riders of all sizes. This is why our Sender DH platform is now mullet-only.  

Choosing a 29er mountain bike is a matter of sizing and riding preferences. For less experienced riders, we think the most important question is bike fit. The handling benefits of a smaller wheel make a big difference to the riding experience of shorter riders, and that outweighs the performance questions. For experienced riders and racers, the question comes down to your preferences and your riding style. What best suits you as a rider?

We created a series of buyers’ guides to help riders figure out which of our bikes would best suit their riding style. If you are not sure which riding style would suit you, then our bike finder tool takes you through a series of easy questions to help you understand which type of mountain bike might feel best for you. If you have found a few bikes you like, but can’t decide between models, then our bike comparison tool compares bikes head-to-head so you can see the differences.

Mountain bikers have wasted many words online debating wheelsize online over the years. We think that if you can find a bike that fits you, your budget and your riding style, then you are going to have a great time, regardless of how big the wheels are.