What Is A Mullet Bike: Pros and Cons, And Are They Faster Than 29ers?

Mountain biking expert Sonny Evans talks you through the pros and cons of asymmetric wheel setups for MTBs

Photo of author
Written by
reviewed by Rory McAllister
Last Updated:

You’ve all heard the expression: “Business in the front, party in the back”, right?

The term “mullet” might evoke images of  Australians, ’80s Pop singers, and hockey players – but who would have imagined this term making a resurgence in the world of cycling?

A mullet bike is a mountain bike with two wheels of different sizes, most commonly a 29-inch wheel at the front and a 27.5-inch wheel at the rear.

The idea is to combine the key benefits of each wheel size, while minimizing their drawbacks, for a bike that’s lightning-fast and super agile, without sacrificing stability.

Where traditionally mountain bikers have had three wheel-size options (old-school 26″, nippy 27.5″, or now-commonplace 29″), mullet mountain bikes open a whole range of new combinations for bikers to experiment with.

I absolutely love riding my mullet bike and taking advantage of all the benefits of the smaller rear wheel – but not every mountain biker feels the same. So, to give you the lowdown, I’ll be walking you through:

Bernard Kerr charging on a mullet bike at the UCI Downhill World Cup in Mont Sainte Anne, Canada, in October 2023.
Bernard Kerr charging on a mullet bike at the UCI Downhill World Cup in Mont Sainte Anne, Canada, in October 2023. © Bartek Wolinski/Red Bull Content Pool.

What Is a Mullet Bike?

A mullet bike is a mountain bike with a large wheel at the front and a smaller one at the rear – typically 29″ and 27.5″, though other sizes can be used too.

Putting all the recent hype aside, asymmetric wheel setups aren’t all that new. Arguably, penny-farthings are the oldest predecessor to mullet bikes!

However, much has changed in bike design since then, and in the brief history of the modern mullet bike, a few factors have hindered its rise in popularity.

Back in 2002, Specialized released the first commercially available mullet bike, called the “Big Hit”. Featuring a 26-inch front wheel and a 24-inch at the rear, the Big Hit was (ironically) met with mixed reviews.

Why? Unbalanced geometry, a heavy frame, a limited selection of 24” tires, and ultimately, poor marketing led Specialized to discontinue the pioneering Big Hit mullet bike just a few years later.

In 2009, Trek took a shot at the mullet bike with its “69er”, boasting a 26-inch rear wheel and a 29-inch front wheel, but the concept still failed to catch on, besides a handful of pioneering mountain bikers swapping out their wheels to make DIY mullet bikes at home.

This was largely because the UCI (Union Cycliste Internationale) had ruled that both wheels must be the same size, irrespective of the cycling discipline.1Regulations. (n.d.). Union Cycliste Internationale (UCI). https://www.uci.org/regulations/3MyLDDrwJCJJ0BGGOFzOat

This rule was specifically to ensure cyclists weren’t leveraging the aerodynamic advantages of running a smaller front wheel on track bikes in the velodrome, but the rule still applied to mountain biking too nonetheless.

It wasn’t until World Cup Downhill teams made the case that these regulations were not relevant to off-road disciplines that the UCI finally relented and allowed mountain bike teams to run asymmetric wheels on their bikes, beginning in the 2019 season.

This sparked a comeback for mullet mountain bikes and manufacturers started to release frame models specifically adapted for mixed wheel sizes.

With the advent of e-bikes, manufacturers such as Canyon and Vitus have also adopted the mullet setup on their new bikes. Within the last two years, mullets have made a rapid resurgence, particularly within the downhill and enduro racing world.

8 Pros of Mullet Bikes 

1. Slackened Geometry

Diagram demonstrating head angle on a mountain bike.
Diagram demonstrating head angle on a mountain bike. © Robbie Ferri/BikeTips

Slacker geometry refers to a more reclined head tube angle in bikes.

In simple terms, slacker head tube angles enhance stability and control on challenging terrains at the cost of responsiveness.

With a bigger wheel at the front, mullet bikes inherently have slacker head tube angles, as the center of the front wheel is higher than that of the rear. This is especially true if it’s a “DIY” mullet bike – in other words, a rider has swapped a wheel on a regular MTB frame.

Incorporating slacker geometry into mullet bikes optimizes the balance between stability and maneuverability of a diversity of terrains, thus significantly enhancing the rider’s control and confidence during off-road cycling experiences.

This makes them especially well suited to downhill and enduro mountain biking, in which slacker geometry is generally favored to provide stability at high speeds and reduce steering twitchiness.

2. Improved Control

As well as the slacker head angle providing extra control, larger wheels inherently provide a smoother ride over bumps and lumps.

By their nature, big wheels have better rollover than small wheels, meaning they judder less over small obstacles on the trail.

Experienced mountain bikers will also know that a 29er can withstand larger shocks, drops, and jumps than an MTB with 27.5″ wheels, which in turn provides more control for navigating difficult terrain.

Because much of this impact comes from the front wheel, mullet mountain bikes can draw out much of the benefit of a 29er setup in this regard without some of the sacrifices that come with a larger wheel at the rear.

3. Great Agility

The smaller rear wheels can stick to an inside line with ease, perfect for those competitive riders who want speed without compromising maneuverability and allowing you to whip through tight corners.

Loic Bruni on a mullet bike at the Downhill World Cup in Lenzerheide, Switzerland in June 2023.
Loic Bruni on a mullet bike at the Downhill World Cup in Lenzerheide, Switzerland in June 2023. © Bartek Wolinski/Red Bull Content Pool.

4. Reduced Weight  

A drawback of regular 29ers is the added weight of larger wheels. But with a mix-matched mullet setup, you can take advantage of the same shock resistance control with a lower weight due to the smaller back wheel.

However, while the reduced weight on the rear wheel can make the bike feel more agile, it’s worth remembering that for downhill mountain biking specifically (a key area in which mullet bikes are popular), weight in general isn’t that much of a priority, given you’re exclusively riding downhill.

5. Increased Customizability

Don’t fancy the mullet today? No problem. Since mullet bikes have become more and more popular, manufacturers have begun to develop frames that offer the flexibility to cater to both traditional and mixed-wheel mullet setups.

6. Shorter Wheelbase

With a smaller rear wheel, the overall wheelbase of the bike is shortened. In general, a shorter wheelbase provides added agility to the bike’s handling.

This is particularly important for electric mountain bikes, as the frames tend to be longer in order to accommodate the battery, motor, and any other additional tech required.

7. Extra Rear Clearance

A smaller rear wheel provides extra clearance at the rear.

This is a bonus on steeper trails as it makes sudden drops easier to handle, as the rear wheel is likely to kick up into your butt. This benefit will be particularly noticeable to shorter riders, for whom this is a common issue with 29er wheels.

8. They’re Fun!

Mullets are different. You might have a spare wheel from another bike or you’re just looking to experiment. Mulleting your bike is a cheaper way to completely change your riding experience.

Why not try something new?

Richie Rude descending on a mullet bike at the Downhill World Cup in Mont Sainte Anne, Canada in October 2023.
Richie Rude descending on a mullet bike at the Downhill World Cup in Mont Sainte Anne, Canada in October 2023. © Bartek Wolinski/Red Bull Content Pool.

5 Cons of Mullet Bikes

1. Balance

While mullet bikes are hailed for their adaptability and performance across varied terrains, they come with their own set of challenges – particularly when it comes to balance.

Obviously, mullet bikes are fundamentally less balanced than equivalent symmetrical-wheel versions. This can make the bike feel less balanced when navigating climbs in particular. Riders might find themselves exerting extra effort to maintain stability and control. 

This can also affect the rider’s posture and body positioning on the bike.

2. Availability 

Mullet bikes are still fairly new within the cycling world. This shouldn’t be a problem if you’re skilled at bike maintenance and happy to “Frankenstein” your own mullet bike together.

But if you’re looking for an off-the-shelf mullet bike, you might struggle to find one within your price range that fits your exact needs that’s readily available.

3. Cost

As these are still new and emerging phenomena, mullet bikes will be priced a little bit higher than standard bike setups. In comparison to symmetrical-wheel bikes, there’s a lot less choice and range to pick from.

For this reason, novice riders on a budget might struggle to afford a mullet bike.

4. Aesthetics

Aesthetically speaking, mullet bikes may not be everyone’s cup of tea.

Much like the iconic haircut, these bikes prioritize function over form. The asymmetry of wheel sizes can give the bike an unconventional appearance, which might not appeal to riders who prefer the more traditional, symmetrical look

While the practical benefits are undeniable, riders should weigh their aesthetic preferences alongside performance considerations when exploring mullet bike options (if looks matter to you).

5. Oversteer or “Drift”

As 29-inch tires offer greater grip than smaller ones, the rear wheel is likely to lose traction first when cornering, resulting in oversteer or “drift”.

This isn’t necessarily a major issue as an experienced rider can handle oversteer by countersteering – for some this could even add to the fun of the ride.

It’s certainly preferable to understeer too (the front losing grip before the rear), which is much more likely to result in a crash – so if you’re struggling with understeer on your setup, shifting the balance to oversteer could even be an advantage.

Personally, I love this aspect of mullet bike handling. Switching out my 29″ rear wheel for a 27.5″ brought the bike’s handling to life, and I found it great fun flicking the rear around corners, especially since I generally ride for fun rather than competitively against the clock.

However, for less experienced mountain bikers, a twitchy rear end that’s sliding around more than they’re used to could pose a danger of crashing. For racers, sliding around a corner is also often a slower way to get around it than maintaining traction all the way round.

So, I’ve included it as a disadvantage here for caution’s sake – but consider it a disadvantage with a heavy asterisk.

Finn Iles drifting a mullet bike on a steep berm.
Finn Iles drifting a mullet bike on a steep berm. © Paris Gore/Red Bull Content Pool.

Are Mullet Bikes Faster Than 29ers?

This depends on a vast range of factors, such as the rider’s physique and personal preferences, the terrain and layout of a particular trail, and even the weather.

This test by Pinkbike found a marginal advantage (under 1%) for a mullet bike in terms of pure time versus a like-for-like 29er on the same trail, with the same rider, in the same conditions.

However, given how many variables there are, a 1% advantage isn’t statistically significant enough for us to say that mullet mountain bikes are faster than 29ers as a blanket statement.

1% is small enough that a different rider on a different day could have the opposite result – and anecdotally, some mountain bikers I’ve spoken to have had that experience.

That being said, it’s pretty clear that there’s no real overwhelming evidence that mullet bikes are inherently slower either, so if that’s what’s been putting you off giving a mullet setup a go, it shouldn’t be!

In fact, immediately after the UCI legalized mullet setups for racing, the very first round of the 2019 Downhill World Cup in Maribor, Slovenia was won by Loic Bruni (previously a noted 29er-hater) with Danny Hart in second – and both were riding mullet bikes.

If it’s quick enough to win World Cup races, then that’s pretty good proof-of-concept for mullet bikes as far as I’m concerned!

Should You Buy a Mullet Bike?

It’s a decision as personal as your favorite trail! 

Ever find yourself tackling a mix of terrains, wishing for the steadiness of a 29er on tricky sections, yet craving the agility of a smaller wheel when the trail gets tight? A mullet bike could be the perfect trail companion for you.

That said, there’s no universal answer here. It’s all about the feel, the ride, the connection between you and the bike.

My advice? Hop on a variety of bikes, mullet setups included, and experience the ride. See how in control and comfortable you feel, and how well it handles your favorite terrains.

Mullet bikes are like the Swiss Army knife of the cycling world – versatile and adaptable. The larger front wheel glides over obstacles, offering a smooth ride and control, while the smaller rear wheel makes those sharp turns feel like a breeze. 

But, again, it all boils down to personal preference. What works for one might not work for another. After all, the best trail bike for you is the one that feels most natural. 

So, try, test, feel, and let your riding experience guide your choice. Good luck! 

Photo of author
Sonny is an avid biker and cycling writer based in London, United Kingdom. Though he loves road cycling, his true passion is shredding long-distance bikepacking and mountain biking routes on his custom Kona Dew Plus. In the city, Sonny commutes on his beloved fixie, a vintage track bike which he painstakingly rebuilt and repainted at home.

Leave a Comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.