Mountain biking has evolved, and wheels have been key in this transformation. The arrival of Plus wheels in 2016 offered an intermediate option between standard tires on mountain bikes (2.1” - 2.5”) and fatbikes (3.5” - 4.5”). Fatbikes excel in extreme terrains, but their lower versatility drove the demand for more balanced options. Plus wheels (2.8” - 3”) offer greater traction and comfort without sacrificing performance, becoming a popular option for full suspension mountain bikes for technical descents and for hardtail mountain bikes, improving shock absorption. Here we explain their main features and the pros and cons of riding with Plus wheels in 27.5” and 29”.
Wheels of rapid rise and decline
Mountain bikes with Plus wheels experienced a strong boom between 2016 and 2018, only to soon suffer a decline and gradual disappearance from the catalogs of the main brands, except in the eBike segment, where they have found their place. The main reason for this rapid rise and decline is the recent evolution of 29" wheels with rims over 30 mm internal width, fitted with reinforced sidewall tires to prevent unseating. These thus manage to provide the extra traction and stability that Plus wheels offer. Similarly, Plus wheels did not gain the endorsement of competitive cycling, an important testing ground for the discipline’s constant innovations, which are later adapted for the regular user. Plus wheels do not provide speed and agility, but quite the opposite. Due to their larger tread, they drag when rolling, especially uphill, and slow down handling on descents.
Main advantages of Plus wheels in mountain biking
Although their presence in new bike builds has decreased, there are still brands that maintain compatibility between 29" and 27.5" Plus, keeping a wide wheel clearance to accommodate either wheel depending on the biker's needs. This is the case of the Trek Roscoe, which comes standard with 27.5" Plus wheels (2.8" width), but can also be fitted with 29" wheels up to 2.4" wide. Likewise, Plus wheels are common on eBikes, where the extra weight is not a problem, since there is a motor to assist pedaling. In addition, they provide extra traction and control on already heavy bikes, which in many cases exceed 20 kg. If you are a beginner biker with a low technical level and are not obsessed with speed, mounting 27.5" Plus wheels with 2.8 or 3" width will give you greater traction on descents, jump landings, and winding trails with many curves, as well as when climbing. Furthermore, with Plus wheels you can overcome, without risking losing balance, sand banks, muddy stretches, or even snow, thanks to the larger tread surface.
Drawbacks of Plus-size wheels in mountain biking
The increased traction and stability provided by Plus-size wheels come with a series of drawbacks, such as the greater weight of the rim, since it is wider, and the larger contact area between the tire and the ground, which slows down your pace when riding or climbing. The weight is kept in check by manufacturing the tire with lighter compounds. However, it is highly recommended to convert both wheels to tubeless to prevent the weight from skyrocketing, allowing you to ride at lower pressures than recommended. Adjusting the pressure of Plus-size mountain bike wheels can be both an advantage and a disadvantage at the same time. While you have a wider range of customization to adapt to a more or less technical route, it is not always easy to find the right pressure. If it's too low, you'll climb with a lot of drag and cornering will be slower. On the other hand, if you put in too much air, you'll feel like the wheel bounces too much when going over rocky areas or jumps, increasing the risk of losing control of the bike. That's why choosing the correct pressure can give you more headaches than a conventional MTB tire.
Think carefully before switching to Plus-size
If you are attracted to large wheels like the Plus-size, you should take into account the advantages and disadvantages we've explained. Consider what such specific wheels can offer for your daily rides and whether it is worth getting a bike with this wheel size or simply changing the wheels. If you are going to buy a bike with stock Plus-size wheels, make sure to check its compatibility with other types of wheels and tires, in case you want to adapt it with more agile conventional wheels in the future. Also, consider the weight of the frame and the wheels. An aluminum version of both can be very heavy. On the other hand, making a financial effort to get one with a carbon frame will be worth it, saving a couple of kilos on the scale, which you'll appreciate on climbs. If, instead, you just decide to swap out the wheels, remember that your bike's frame must be compatible with this standard, having a wide enough clearance to install them without risk of rubbing or mud accumulation. Also, keep in mind the added weight of these wheels, whose rim width is larger. At this point, opting for carbon fiber rims is ideal, but it will require a significant investment.