What Is a Mullet MTB? Key Features, Pros and Cons

What Is a “Mullet” MTB?

In mountain biking, a “mullet” refers to a bike setup that uses different wheel sizes for the front and rear. This configuration has become increasingly popular in recent years.

Many MTB manufacturers now offer mullet versions of their bikes, often labeled as “Mullet” or “297” in the product name—indicating a combination of a 29-inch front wheel and a 27.5-inch rear wheel. As a result, it’s common to see both standard and mullet configurations within the same product series.

While the term “mullet” generally implies a 29/27.5 setup, it technically refers to any mixed wheel size configuration. Other combinations, such as 27.5-inch front with 26-inch rear, also fall under this category.

Key Features of Mullet MTBs

Historically, MTBs primarily used 26-inch wheels. Eventually, the industry shifted toward 27.5-inch wheels to improve rolling performance. More recently, 29-inch wheels have gained dominance—especially in cross-country and trail categories—thanks to their superior rollover and momentum-carrying abilities.

Mullet bikes emerged from this evolution, offering a blend of strengths: a 29-inch wheel in the front for better rollover and stability, and a 27.5-inch wheel in the rear for agility and improved handling in tight corners.

Advantages of Mullet MTBs

The biggest advantage of a mullet MTB is that it offers the “best of both worlds.”

• Improved front rollover & stability: The 29-inch front wheel helps absorb obstacles and boosts straight-line performance, ideal for high-speed descents and technical terrain.
• Enhanced rear maneuverability: A smaller 27.5-inch rear wheel offers better agility, quicker turning response, and improved traction. It also lowers the rear end of the bike slightly, making it easier to control for shorter riders and reducing the chance of tire contact with the rider’s body during steep descents.

Another benefit is greater flexibility in tire setups. Because the smaller rear wheel increases frame clearance, you can often install wider tires than with a 29-inch setup. This allows for increased air volume, which can enhance comfort and traction on rough trails.

Disadvantages of Mullet MTBs

The primary drawback of mullet MTBs is that the setup can feel like a compromise.

Some overseas riders have tested mullet conversions—such as swapping a 29-inch front wheel onto a 27.5-inch MTB—to see how speed and ride quality change. However, many report that the difference is not noticeable in real-world riding.

Additionally, since the front wheel is larger, it tends to be heavier. This often results in a front-heavy bike compared to models with equal-sized wheels, potentially affecting handling and balance.

How to Choose a Mullet MTB (and What to Watch Out For)

When shopping for a mullet MTB, consider the following points:

1. Can the bike run both same-size and mixed-size wheels?
2. Is the geometry optimized for a mullet setup?

Because mullet setups use different wheel sizes, the front of the bike ends up higher than the rear. To be specific:
Assuming identical tire models, a 29-inch rim has a bead seat diameter (BSD) of 622mm, and a 27.5-inch rim has a BSD of 584mm.
So: 622 / 2 - 584 / 2 = 19mm — that’s nearly a 2cm increase in front height.

If the bike geometry isn’t optimized for this, it may result in a “nose-up” stance or a slacker front angle, which can affect performance.

Although 2cm might sound minor, riders often notice the height difference just by straddling the bike after switching from 27.5 to 29 inches.

If these geometry changes (like front-end height and head angle) suit your riding style, a mullet setup could be a great fit. However, stack height and front angle are critical factors in how the bike handles—so it’s best to consult with a specialist at a sports bike shop before making a purchase.

Can You Convert an Existing MTB to a Mullet Setup?

Some modern MTBs are designed with flexibility in mind. Even if they’re originally 27.5-inch bikes, they may have geometry that accommodates 29-inch wheels or offer adjustable dropouts to switch wheel sizes. Bikes that support wide 27.5 x 2.8" “plus-size” tires can sometimes be converted to 29 x 2.2" wheels without drastically affecting the geometry.

What About Converting Non-Mullet-Ready Bikes?

Problems arise when converting a bike that wasn’t designed with a mullet setup in mind.

For example, turning a 27.5-inch MTB into a mullet (by installing a 29-inch front wheel) raises the front end by several centimeters. This also slackens the head angle slightly and lifts the bottom bracket height, due to the increased front axle height. The result: an overall taller bike. That extra height shifts the center of gravity upward, which can noticeably change ride feel and may reduce stability.

Conversely, if you convert a 29-inch MTB to a mullet by installing a smaller 27.5-inch rear wheel, the geometry changes similarly (the front is still higher), but the rear of the bike lowers and the bottom bracket height drops. That puts the crank area closer to the ground, which can cause the frame or crankarms to strike the ground—especially on full-suspension bikes when the rear suspension compresses.

Key Takeaway

Because mullet conversions significantly affect geometry, handling, and ride safety, it’s essential to understand the trade-offs. If you’re modifying your bike with a clear goal in mind, it can be worthwhile. But if you simply want to “try out a mullet,” it’s best to work with a professional shop to ensure a safe and effective setup.