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Choosing Between A 29er or A 27.5 Mountain Bike

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December 30, 2020

29 inch next to a 27.5 inch mountain bike wheel

A few years ago, choosing a mountain bike was easy. Once you had settled on the style and geometry of your preferred bike, you only had one wheel size option – the standard 26-inch. But since the 29-ers and 27.5 inch wheels were introduced, there has always been a battle of wheel supremacy regarding which wheel size is the best.

Recently, wheel sizes are heavily debated on bike forums and sites almost every day. Sometimes, it even creates a division between which wheel size is better, but it’s a personal preference, and nobody is wrong.

The 29ers are mostly the go-to option for tall riders or mountain bikers who prefer technical terrains more as they provide more traction and stability. For the shorter riders or those who prefer a playful riding style, the 27.5 inch is the best option as it accelerates faster and is more maneuverable.

With the two seemingly great options available, you might struggle to decide which one is best for you. To help make the buying process easier, below, we’ve discussed in detail what you can expect from each wheel.

 

mtb wheels

Acceleration

27.5 in. have faster acceleration compared to the 29ers due to the size of the wheel.

To put this into perspective…

A 29-er bike is like a ‘buggy on steroids.’ It is slow to accelerate due to the huge wheels but will ride over the toughest of terrains – perfect for going over huge ruts and rough terrain.

Replace the huge tires on the buggy with standard tires, in this case, the 27.5 in, and you’ll have instant acceleration. But then you’ll have sacrificed some of the off-road capabilities.

Small wheels accelerate faster due to the small rolling circumference. Larger wheels are slower because the tire’s height causes the overall weight to be distributed to the spokes, rims, tubes, and tires, farther away from the center of the wheel. This results in higher rotational mass and slower acceleration.

  • 27.5″: most mountain bikers love it because of it’s snappy, responsive feel.
  • 29″: accelerates slowly and takes longer to get up to speed, possibly giving it an unresponsive feel. However, once it’s up to speed, it’s more efficient than smaller wheels because it requires less effort to keep the momentum going.

Ride Experience

Assuming the bikes are the same, the only difference being the wheels, bikes with 27.5-inch wheels are typically more manageable and playful to ride than their 29-inch counterparts.

Because of the smaller wheel diameter, 27.5-inch wheels easily navigate through tight and tricky trails and give the rider a more instantaneous response to immediate situations.

Further, because of their lower weight, 27.5-inch wheels are known to be “playful” because they are light and can change directions quickly, hopping from one side of the trail to the other with less effort. The 29-er feels more sluggish in sharp turns but is great at keeping momentum in shallow turns, feels much more stable.

  • The 27 5 wheel is the best fit for the mountain biker who loves to play and pop over roots, rocks, and other trail features. The small wheel size requires less space to throw around and change direction.
  • 29er wheel is the best option for riders who like to cruise at high speed and plow over things with confidence.

Obstacle Clearance

29ers roll over objects more easily.

The attack angle is the angle made when the wheel touches an object that the rider intends to roll over.

Since 29ers have the largest diameter wheel, they will always have the shallowest attack angle, giving them the upper hand when it comes to riding over objects.

In short, the smaller the angle, the easier it is for the wheel to roll over the object.

29-inch wheels are particularly reliable and stable on rough and speed descents and climb. Many riders feel more confident with larger wheels.

Compared to the 29er, 27.5-inch tires do have a better angle but not as significant.

  • 29er wheels are better at handling objects like rocks, logs, and tree roots. Many riders feel more confident with larger wheels when riding rough terrain.
  • 27 5 wheels don’t roll over objects as easily as 29ers, but they are still very capable. They are perfect for smooth trails.

Bike Wheel Size

A 27.5” Plus and 27.5″

Also labeled as 650b, or ISO 584 mm, both have a smaller diameter than the 29″. This gives the respective bike a great compromise between agility and speed. They are easy to control and accelerate and ride better on trails with few ruts and root outgrowths.

29″ / 700c (ISO 622 mm)

Immediately after its release, the 700c wheel took the mountain bike world by storm, and the “hype” keeps on recurring almost every year. Today, they’ve dominated the MTB world with 29ers bikes such as Polygon, which have gone on to win medals at various world cups. However, saying this, the 29 is best suited to rough trails as the wheel size means it easily rides over most obstacles.

Weight

29 in. wheels are heavier.

There’s no way around it; the larger the wheel, the heavier the bike. A 29er mountain bike with the same structure, geometry, and frame can weigh more than 2lbs more. This is because the wheel requires more wheel material and more tire rubber.

2 lbs might not seem significant, but depending on the type of riding you do, it could mean everything. The added weight can make your bike feel less responsive, requiring more effort to navigate around on winding trails.

If you are the ‘after work or weekend casual rider”, the weight difference may not be your biggest concern. You might care more about the ride experience or attack angle.

If you’re competitive and frequently ride on flow trails or jump parks, you’ll probably be looking for ways to save weight. Choosing a smaller wheel is one of the easiest ways to reduce weight, but it’s not the only way.

Long-distance Cross Country riders also benefit from lighter bikes. They are always trying to reduce the weight; even if it’s just a few grams, you’d think they’d be better off going for smaller wheels.

But it’s not really the case for most competitive mountain bikers.

Tubeless wheels to reduce the overall bike weight and increase the accelerating power. * Larger wheels can accelerate faster because of reduced rotational mass.

You can look into carbon fiber handlebars, seat posts, frames, and rims for an ultralight ride.

 Traction (grip)

The surface area of a wheel helps keep you on the ground, helping you maintain your grip on wet and slippery object trails. There are other factors that influence traction, but mainly, the larger the contact patch area, the more grip you have.

Because 29-inch wheels have a larger contact patch, they provide better grip (traction) compared to 27.5″ wheels. 29er mountain bikes ride smoothly over slippery objects such as roots, especially in wet conditions.

  • 29er. They already have a better attack angle – the extra grip makes it even better on rough terrain.
  • 27 5 in: Don’t underestimate 27.5 bikes, though. They still have a reliable grip. If you really want that extra traction, you can consider getting the 27.5 Plus. It has the same wheel diameter as the 27 5, but it’s deeper, wider, and has more volume. It still has the same properties, a normal 27.5 but with added traction

27 5 Plus offers more traction and is better for soft sand, slippery surfaces, and muddy conditions. Like in a car, by reducing the tire’s air pressure, the 27.5 Plus deals even better with obstacles and rough terrain.

Which Wheel Size Should I Choose?

To make a more informed decision, we’ve highlighted the perks and cons of each wheel size.

What are 29er MTBs best for?

There is no getting around the fact that bikes with 29-inch wheels feel huge. The rider seems to sit inside the bike rather than on top of it. From the first crank rotation, you instantly notice that the smaller wheels’ snappy response is gone.

But once you start riding, you will appreciate how the wheels maintain momentum and speed.

Being exceptional climbers, they are a pretty much solid and comfortable choice for most riders. So, if you plan on riding a lot of XC trails with climbs and long stretches, the 29er is your best option.

29’er Cons.

  1. They Accelerate slower
  2. Shorter riders often get hit in the butt when descending steeps due to the rear’s large size wheel.
  3. The increased momentum of the larger wheel makes direction changes slower.
  4. The larger wheel size demands a longer rear chainstay and less rear travel.
  5. Not as strong or stiff as the 27.5 wheels.

What are 27.5″ MTBs best for?

Being in the middle, between the 26ers and 29ers, the 27.5 in is built to be a great all-arounder, and it sure does stay to its purpose.

Offering the responsiveness of the 26 in and the additional rolling ability of the 29ers, the 27.5 bikes provides a solid option for a rider who is looking for a bike that can do it all – compete in areas like Downhill racing or Jump Parks, ride on bike parks, flow trails.

This is also a solid option for any rider looking for a bike that can do it all.

27.5″ Cons.

  1. Not stable at high speeds
  2. Falls into holes easier
  3. A smaller contact patch gives less grip and braking than the 29er.

What about my 26er?

If you bought your bike over 10 years ago, you might still have the 26-inch bike.

Today, the wheel size has mostly been abandoned and is usually used in kids’ bikes and dirt jump bikes. The only option is to upgrade to either 27.5 or 29er. The new mountain bike wheel sizes are better in every aspect as we’ve described above compared to the 26er.

27.5 and 29 Mullet Bike

A mullet bike is one that uses both wheel sizes – most commonly, the bigger 29″ wheel goes up front and the 27 5 inch wheel in the back. Some bike brands already sell mixed wheel size bikes as standard, especially eMTB brands.

When looking at the picture of a mullet bike, it looks great, offers the best of both worlds –the 29″ front wheel provides grip and flawless rollover while the flickable rear wheel provides agility and less rotational weight.

Also known as the 297, the Mullet is “business up the front, party in the back.”

Should I Mullet My Mountain Bike?

First, it’s not as easy it looks.

Changing the wheel size of your bike can be expensive. At the very least, you will need a new wheel and tire, but if your bike wasn’t formerly built to accommodate such a large wheel, you’d probably need a new fork and possibly a new bar and stem.

The geometry of your bike might also be largely affected, requiring correction. When done properly, a mulleted bike will :

Increase ass clearance: If you often ride a 29er down very steep trails, it’s common to get kicked up the butt when you hit steep drops. By fitting a smaller rear wheel, you have more clearance from your ass whenever you ride rough.

Experience livelier cornering: 29ers can be a bit of a handful in corners. Swapping in 27 5 inch wheels to the rear helps to improve the cornering stability. The smaller shapes make it easy to flick from side to side, and you will have more clearance for gymnastic shapes.

Have a slacker geometry: If you love racing downhill, you may have tried, own, and already love the increased stability of a bigger 29″ front wheel. If you want to get more speed, mulleting your bike helps to slacken out the head-angle to reduce rolling resistance, speeding up your ride.

Be cooler: If you want to try something fun with your bike, mulleting it could be an awesome experiment. Of course, depending on the type of bike, results aren’t always guaranteed. But hey, that’s why DIYs are fun! You rarely know what the end result is until you are done and testing.

 

mullet a mountain bike

Can a Short Person Ride a 29er?

Yes, they can…

Although on most 29er bikes, the wheelbase and bike geometry support a larger rider, small frame sizes have been built to fit smaller riders.

If you are not sure or want advice on the best option based on your criteria and needs, leave a comment below, and we’ll be happy to help.

How tall should you be for a 29-inch bike?

The rider’s height is one human genetic attribute that affects the choice of mountain bike wheel size.

Riders with a height between 5’5 and 6’2 are considered lucky as they can comfortably ride on either wheel size. People under 5’5″ are generally within the 27.5 in. jurisdiction, and those from 6’2″ and above fit 29-inch bikes best.

29″ vs. 27.5″. Which Is Better?

There is no clear winner on this. The ultimate decision should come down to what you like and what fits best with you.

Convenience, fit and riding style should play a role in your choice of wheels.

But, no matter the size you choose, 29 and 27.5 wheels will be dominant for a long time.

It will be years before the “best wheel size” debate is over. Whether it’s a 29ers, a 27.5, or a 27.5+, you, as the rider, are the only true difference.

You can choose any bike, practice, and adapt to deal with the advantages and disadvantages of using your skills. Workaround the limitations of your bike and build confidence.

Another important fact that you should consider before choosing the right wheel size is the terrain you’ll be riding on.

There are so many variables to consider when purchasing a mountain bike.

In a nutshell, if everything is equal;

… 29ers favor tall riders who enjoy relatively straight singletrack with few hairpins turns

…27.5-inch wheels are perfect for fairly short riders who enjoy tight and twisty trails

…Define your priorities and how you feel on the bike, then test each of the different wheel sizes before making your decision

Related Questions

Do 29ers climb better?

Practically, bigger wheels are heavier, which works against the rider when climbing, so in this respect, the 27 5 will win. But, if the climb is littered with steep steps and rocks, the bigger 29er rolls over the momentum sapping obstacles effortlessly.

Skilled riders on small wheels may pump, pop, and hop over the obstacles while maintaining their momentum, but this, in turn, drains their energy and will wear them down over time.

So yes, 9ers are better climbers at low speed on a rough surface, but the smaller and lighter 27.5 wheels may hold the advantage on clear/smoother hills or stop/start style switchback climbs.

Do 29ers climb better?

You can still do some pretty huge jumps with 29ers. But, since the 29er doesn’t accelerate quickly, you won’t quite get as much altitude as you would with a 27.5-inch bike. You’ll also get tired fast as you have to pedal harder in between or up to the bumps to get enough speed for a jump. 27.5 is the better option.

Is a 29er good for downhill?

29ers dominate world Cup downhill races. Whenever a trail points down, most downhillers and enduro riders opt for the 29er.

Finally…

Mountain bikes are awesome for adventures and tackling rough terrain, and here at BeastieBikes, we review the best mountain bikes.

If you want to experience the world of thrilling mountain bike adventures, you can check some of our bike reviews here. We hope our guides will help you find the perfect MTB companion.

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About the author 

Beastie Bikes Pete

Hi I'm Pete. I'm a passionate mountain biker in Australia. I enjoy writing about biking as much as doing it......almost!

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