Currently, the 29” wheel size for mountain bikes is the undisputed standard in the discipline. It has eclipsed and practically rendered 26” wheels obsolete and pushed 27.5” wheels to the sidelines. The idea of buying a bike with these latter sizes seems to no longer make sense. For many, it’s practically a waste of money. But is this true? Or is it just another one of those dogmas that have been established in the cycling market? We answer these questions, explaining in detail what the benefits of the different small wheel sizes for mountain bikes are and how important their selection is.
Evolution of Wheel Sizes in MTB
First, it is necessary to put into context why this evolution in wheel size has occurred in mountain bikes. In the 1990s—the decade of global growth and adoption of this sport—26-inch wheels (with an inner diameter of 559 mm) became the most widely used standard. Brands opted for this slightly smaller size compared to road bikes for several reasons. It achieved the ideal adaptation to the heavier frame and geometry and also to the shorter gearing of a mountain bike. With 26” rims, the best possible balance between pedaling and handling was achieved on those bikes.
Why has the wheel size increased?
26” wheels were the standard that remained the sales leader for the most years. But starting around 2012, the main brands (Specialized, Cannondale, Trek, etc.) decided to increase the wheel diameter to achieve better performance. All this without sacrificing key aspects such as agility or handling of the bike on the most challenging trails. The evolution of bike frames played a big role in this decision. The spread of high- to mid-range carbon frames made it possible to create lighter and more compact bikes without sacrificing strength or stiffness, and even increasing them. This allowed for the assembly of larger wheels: 29” for XC and 27.5” for trail and enduro, mainly, without causing the weight or size of the bike to skyrocket.
The manufacture of increasingly lighter and more compact frames made it easier to mount increasingly larger wheels
However, the first generation of mountain bikes with 29” wheels it did not achieve the expected sales success. They were slow to maneuver, heavier than the 26” ones, and not very functional for medium and short-height cyclists. It took a few years until, starting in 2014 and 2015, the frames shed grams and perfected their geometry, thus achieving the perfect fit with such large wheels. From there, faster 29” bikes emerged (larger wheels mean greater inertia), which were lighter and more manageable. With the 29”, a new standard was established that eventually displaced the 26” wheels for good and left the 27.5” ones reserved for more radical disciplines such as all mountain and enduro.
Is it worth buying a 26" or 27.5" bike?
Once the reasons for this rapid evolution to larger wheels have been clarified, you might still be wondering why there is so much debate about wheel size in mountain biking. Is it really that important? We have to answer yes. Manufacturers develop their bike frames depending on the chosen wheel size. In addition, the assembly of components, tires, axles, handlebars, and brakes are also chosen based on the wheel size. Hence its crucial importance in the behavior and handling of the bike. Therefore, when buying a new or second-hand mountain bike, the first thing you should look at, even before the price or design, is the wheel size. We have already explained why 29” bikes currently dominate. But their success has not completely ended the 27.5” or even the 26” bikes. Brands have not yet managed to solve certain imbalances and gaps caused by the increase in diameter. Imbalances that are not as present in 27.5” and 26” bikes. That is why they still survive with their own market niche (although increasingly smaller). So, we must tell you that depending on your needs and the type of cyclist you are, you should not automatically buy a 29” bike. In some cases, it may be worth buying a 26" mountain bike or a 27.5”. We detail the situations and recommended uses for both sizes.
What are 26" bikes recommended for?
26” mountain bikes are out of fashion, but not forgotten or completely obsolete. They are still being sold, intended for specific uses:
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Entry-level models or occasional rides: If you have just started mountain biking or ride occasionally on short and easy routes, a 26” can be a great option due to its low price and functionality. In this regard, we recommend looking in the second-hand market, where you can find a greater variety of models with quality setups at very attractive prices.
- For children or teenagers: 26” wheels adapt better to small frames and are more manageable and lighter, perfect for younger bikers.
What are 27.5" bikes recommended for?
In recent months, there has been much debate in forums and specialized media about the decline of 27.5”. But we are clear: 27.5” still have a lot of commercial life ahead and presence in the market, for several reasons:
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Recommended standard for radical MTB: especially for beginner or intermediate levels and riders of short stature. Its balance between speed, acceleration, agility, and handling is even greater than what you can get from a trail, enduro, or 29” DH.
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For small sizes: this greater balance is also optimal for people of short stature (up to 1.70m or shorter). For this reason, the major brands still offer new models with 27.5” setups in XS and S sizes.
- Rise of the MTB Mullet (29 – 27.5”): finally, we must not forget the rise of MTB mullet bikes. These are conventional or electric bikes that combine a 29” wheel in the front and a 27.5” wheel in the rear. The goal is to obtain a bike that is agile in corners and accelerations and fast or efficient at the same time. If this is what you want in a mountain bike, you should definitely look at mullet setups.
In light of the data we have presented, we advise you not to get carried away by the 29” craze and immediately rule out any bike with smaller diameter wheels. In certain circumstances, whether due to your height, the type of mountain biking you practice, your skill level, or your budget, it may be better for you to buy a 27.5” or even a 26”.