Mountain bike wheel size has changed dramatically over the years. While 27.5-inch wheels were once the go-to choice for many riders, 29-inch wheels have become extremely popular across trail, enduro, cross-country, and downhill bikes. At the same time, another setup has become increasingly common: the mixed wheel, or “mullet,” setup, which combines a 29-inch front wheel with a smaller 27.5-inch rear wheel.
So, which is better: a full 29er or a mixed wheel setup?
The answer depends on how and where you ride, your preferred handling characteristics, your bike's geometry, and even your height. Neither setup is universally better. Each has advantages that can make it the better choice for a particular rider.
What Is a Full 29er?
A 29er is a mountain bike equipped with 29-inch wheels on both the front and rear. The larger diameter gives the wheels a shallower attack angle when encountering obstacles. This allows them to roll over rocks, roots, and other trail obstacles more easily than smaller wheels. Larger wheels can also carry momentum effectively and provide a larger contact patch when paired with comparable tires. For many modern mountain bikes, 29-inch wheels have become the standard choice, particularly for trail and cross-country bikes.
A full 29er generally prioritizes:
- Stability
- Momentum
- Rollover capability
- Traction
- High-speed confidence
- Efficient rolling over rough terrain
What Is a Mixed Wheel or Mullet Setup?
A mixed wheel setup, commonly called a mullet, combines two different wheel sizes on the same bike. The most common combination is:
29-inch front + 27.5-inch rear
The idea is to combine some of the benefits of both wheel sizes. The larger front wheel provides the rollover capability, traction, and stability associated with a 29er, while the smaller rear wheel can make the bike feel more agile and playful. The smaller rear wheel can also provide additional clearance for the rider and make it easier to move the bike around underneath you. However, a mixed-wheel setup isn't simply a matter of swapping a 27.5-inch wheel onto any 29er. Changing wheel size can affect the bike's geometry, including bottom bracket height and head angle. Some manufacturers specifically design bikes to accommodate both configurations, sometimes using an adjustable flip-chip or similar system to maintain appropriate geometry.
Pros of a Full 29er Setup
Better Rollover
One of the biggest advantages of 29-inch wheels is their ability to roll over obstacles. The larger diameter creates a shallower attack angle, allowing the wheel to move over rocks, roots, and other obstacles more easily. This can be particularly noticeable on rough, technical trails.
Excellent Stability
A full 29er tends to feel stable and planted, particularly at higher speeds. The larger wheels can help smooth out rough sections of trail and maintain momentum, making a 29er a popular choice for riders who prioritize speed and confidence.
Strong Traction
Larger wheels can provide a larger contact patch when comparing similar tires, which can contribute to increased traction. This can be especially useful when climbing technical sections or riding over slippery rocks and roots.
Maintains Momentum Well
Once a 29er is moving, its larger wheels are good at maintaining momentum. This can be beneficial on longer climbs, fast sections of trail, and rough terrain where maintaining speed helps the bike carry through obstacles.
Predictable Handling
A full 29er offers a consistent wheel size at both ends of the bike. The front and rear wheels interact with obstacles in a similar way, which can give the bike a predictable and balanced feel.
Cons of a Full 29er Setup
Can Feel Less Playful
The same characteristics that make a 29er stable can also make it feel less nimble. Compared with a smaller rear wheel, a 29-inch rear wheel can take a little more effort to move around, especially when you're trying to quickly change direction or get the rear end off the ground.
Larger Wheels Can Add Weight
Larger wheels and tires generally require more material, which can result in additional weight compared with smaller wheels. The rotational mass of the wheels can also influence how quickly the bike accelerates. Of course, modern carbon rims and lightweight tires can reduce the difference considerably.
Can Be More Challenging for Shorter Riders
A 29-inch wheel takes up more space within the frame and can influence the overall proportions of the bike. Modern frame designs have made 29ers much more accessible to shorter riders, but some riders may still prefer the fit and handling of a smaller or mixed-wheel bike. Rider height and frame design should be considered together rather than using height alone as a deciding factor.
Less Rear-Tire Clearance
The larger rear wheel can require more room within the frame. This is particularly relevant for full-suspension bikes, where designers need to balance rear-wheel clearance, suspension travel, chainstay length, and frame geometry.
Pros of a Mixed Wheel Setup
More Agile Rear End
One of the biggest reasons riders choose a mullet setup is the smaller rear wheel. The 27.5-inch rear wheel can make the back of the bike feel more responsive and easier to move around. This can be particularly useful on tight trails, steep terrain, jumps, and technical sections where you want to reposition the bike quickly.
Playful Handling
Mullet bikes are often described as feeling more playful or dynamic than comparable full 29ers. The smaller rear wheel makes it easier to lift, pivot, and move the rear end, while the 29-inch front maintains much of the rollover and stability that riders expect from a modern 29er.
More Rear Clearance
The smaller rear wheel provides additional space between the tire and the rider. This can be particularly beneficial for aggressive riders who frequently move their body behind the saddle on steep descents.
Keeps the Advantages of a 29er Front Wheel
The front wheel is generally the first wheel to encounter obstacles, so having a 29-inch wheel up front means the bike retains the larger wheel's rollover characteristics and traction where they can be especially valuable. This is one of the main attractions of the mullet configuration: 29-inch stability and rollover up front combined with 27.5-inch agility at the rear.
Can Be Great for Smaller Riders
A mixed setup can be an attractive option for shorter riders who want the rollover benefits of a 29-inch front wheel without having a large 29-inch rear wheel taking up additional space. However, fit should still be determined by the specific frame rather than wheel size alone.
Cons of a Mixed Wheel Setup
Changes the Bike's Geometry
This is perhaps the most important consideration when converting a bike to mixed wheels. Replacing a 29-inch rear wheel with a 27.5-inch wheel lowers the rear of the bike. Depending on the frame, this can alter the bottom bracket height and head and seat angles. That's why it's important to check whether your particular bike is designed to run a mixed-wheel configuration. Some bikes are specifically designed for both setups and use adjustable geometry to compensate for the difference. Others are designed around one wheel size and may not handle properly after a wheel-size conversion.
Reduced Rear-Wheel Rollover
While the 29-inch front wheel will still roll over obstacles effectively, the smaller rear wheel doesn't have the same rollover advantage. On extremely rough terrain, you may notice the rear wheel hitting or hanging up on obstacles that a 29-inch wheel would roll over more easily.
Less Rear Momentum
The smaller rear wheel generally won't carry momentum in exactly the same way as a 29-inch wheel. For riders focused on maximum speed and efficiency over rough terrain, the full 29er may have an advantage.
Different Front and Rear Handling
A mixed-wheel bike intentionally has different characteristics at the front and rear. For some riders, this creates the perfect balance. For others, the difference can take some time to get used to. The bike can feel more active and responsive at the rear compared with a full 29er.
Compatibility
You can't assume that any 29er can simply be converted to a mullet.
You need to consider:
- Frame compatibility
- Fork and front-wheel size
- Rear-wheel clearance
- Bottom bracket height
- Head angle
- Seat angle
- Suspension kinematics
- Tire size
- Manufacturer recommendations
If a manufacturer offers a specific mixed-wheel configuration for a frame, that's generally the best place to start.
Who Is a Full 29er Setup For?
A full 29er is an excellent choice for riders who prioritize speed, stability, traction, and rollover capability.
Consider a 29er if you:
- Ride fast, rough trails
- Spend a lot of time on technical terrain
- Want maximum rollover capability
- Ride long-distance or cross-country trails
- Prioritize maintaining momentum
- Prefer a stable, planted bike
- Race XC, trail, or enduro
- Don't want to worry about mixed-wheel compatibility
For many riders, the full 29er is the best all-around option. It's particularly attractive if your local trails contain lots of rocks, roots, rough descents, and high-speed sections.
Who Is a Mixed Wheel Setup For?
A mullet setup is a great choice for riders who want a more agile, playful, and dynamic bike without giving up the advantages of a 29-inch front wheel.
Consider a mixed setup if you:
- Ride steep and technical terrain
- Like jumping and getting the bike airborne
- Prefer a playful handling style
- Ride tight, twisty trails
- Want easier rear-wheel maneuverability
- Are a shorter rider looking for additional rear clearance
- Ride aggressive trail, enduro, or downhill
- Have a bike specifically designed for mixed wheels
Mullet setups are particularly popular with aggressive riders because the smaller rear wheel can make it easier to manipulate the bike while retaining a confidence-inspiring 29-inch front wheel.
Does Rider Height Matter?
Rider height can influence which setup feels best, but it shouldn't be the only factor. Frame geometry has evolved significantly, allowing riders of many different heights to ride 29ers successfully. A shorter rider may appreciate the additional clearance and maneuverability of a mullet setup, while taller riders may find the proportions of a full 29er more natural. Ultimately, your preferred handling characteristics and the geometry of your particular bike are more important than following a simple height chart.
What About Tire Choice?
Wheel size isn't the only factor affecting how a mountain bike handles. Tire width, casing, tread pattern, and rubber compound can all have a significant effect on grip, rolling resistance, weight, and handling. For example, a rider who wants a fast and efficient 29er can choose a lighter, faster-rolling tire, while an aggressive enduro rider might choose a heavier casing and softer compound. The same applies to a mullet setup. You don't necessarily need identical tire models front and rear. Many riders choose a more aggressive tire on the front for maximum steering and braking traction, while using a faster-rolling rear tire.
Can You Convert a 29er to a Mullet?
Sometimes. The most important word here is sometimes.
If your bike's manufacturer specifically supports a mixed-wheel configuration, the conversion can be relatively straightforward. Some bikes use a flip-chip or adjustable geometry system specifically designed to compensate for the different rear-wheel size. If your bike isn't designed for a 27.5-inch rear wheel, simply installing one could change the geometry in ways that negatively affect handling and pedal clearance. Before buying a new rear wheel, check your frame manufacturer's specifications and recommendations.
Which Setup Is Faster?
There isn't a universal answer. A full 29er generally has an advantage when maintaining momentum and rolling over rough terrain is the priority. The larger rear wheel can also provide excellent traction and rollover capability. A mullet can feel quicker and more responsive when negotiating tight corners, technical sections, or terrain where frequently repositioning the bike is important. The "faster" setup ultimately depends on the trail and rider. A setup that is technically faster on a straight, rocky descent may not be faster for a rider who feels more confident and can corner more aggressively on a mullet.
Full 29er vs. Mullet: Which Should You Choose?
The choice ultimately comes down to what you want your mountain bike to feel like.
Choose a full 29er if you want:
Maximum rollover, stability, traction, momentum, and confidence on rough terrain.
Choose a mixed wheel setup if you want:
A more playful, agile rear end while retaining the rollover and traction advantages of a 29-inch front wheel.
Neither setup is inherently better. The best wheel configuration is the one that matches your bike, your body, your trails, and your riding style.
Final Thoughts
The full 29er and mixed-wheel setups offer two different approaches to modern mountain bike handling. A full 29er is the choice for riders who want maximum stability, rollover, traction, and momentum. A 29/27.5-inch mullet gives up some rear-wheel rollover in exchange for a more agile and playful rear end.
For riders who spend their time on fast, rough terrain, a full 29er can be hard to beat. For riders who love steep descents, tight corners, jumps, and moving the bike around underneath them, a mullet can offer an incredibly fun and responsive ride.
Before changing wheel sizes, always make sure your frame and suspension are compatible with the setup you want to run. Once compatibility and geometry are sorted out, choosing between a full 29er and a mullet becomes much less about which setup is "better" and more about which one makes you want to ride more.
Remember that we offer free shipping on all orders over $149CAD. Orders are all processed and shipped within 24 business hours as well. Looking for mountain bike parts? We stock hundreds of parts from multiple brands and you can shop our entire selection here.
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