29ER VS 27.5 MOUNTAIN BIKE

HOW TO Pick the Right Wheel Size – 29er vs 27.5 vs Mullet Mountain Bike

29er vs 27.5 mountain bike wheels…the debate continues to rage on. When it comes to wheel sizes for mountain bikes, the 29 inch and 27.5 inch wheel sizes have completely taken over the market. The traditional 26” wheel size has been relegated to museum duty (except for kids bikes) as these larger wheel sizes have shown to translate to big benefits on the trail. If you are looking at upgrading your mountain bike, wheel size and suspension travel are your biggest indicators on which bike you will end up buying.

The 29er vs 27.5 Wheel Size Debate

Before we get into my thoughts on each wheel size, I do want to preference that I believe there is no right wheel size for everyone. The topic is heavily debated on forums and other groups enough. The goal here is to evaluate the pros and cons of 29er vs 27.5 mountain biking wheels to see which size would be right for you.

2021 Trek Slash 29er

29ers – What is the big deal with 29inch Mountain Bike Wheels?

29ers have made their way into all aspects of mountain biking. What started off in the hard tail and pure XC part of the mountain biking industry is now seen regularly on the DH circuit. What does the 29er do well…and where do they fall short?

What does a 29er do well?

  • Rolls over rocks and roots easier due to the wider circumference.
  • More distance covered per pedal revolution.
  • Higher air volume in tires smooth out ride.

The larger diameter wheels of the 29er mountain bike can create the sensation of having an 1″ more travel than the bike is spec’ed due to the larger air volume and larger contact patch with the ground. You will often here the term “plow bike” as the 29er wheel just loves to be thrown into just about everything. In really rooty, rocky situations the 29er will roll through it much easier than smaller wheel sizes.

What are the drawbacks of a 29er?

  • Large size equals larger weight.
  • Harder to maneuver in tight, twisty single track.
  • Longer travel (6″ and higher) 29ers can feel REALLY big due to longer wheelbases.
  • Sizing and geometry issues with smaller riders.
  • Larger radius needs stiff wheel build and fork to prevent deflection.

Just as with any big change, it is not all good news. While the true 29er zealots will probably tell you these things are not true, the reality is that you are adding bigger wheels to the mountain so there are going to be negative side effects that go along with the positive changes. 29ers can be slower to turn and the longer platform can not be as nimble, playful as the 27.5” counterparts.

Trek Remedy 27.5

27.5” Mountain Bike Wheels – What do you gain and lose?

The 27.5” wheel size literally cuts the difference between the 29er and 26 wheel size of the past. The original idea with 27.5” wheels was to gain some of the benefits of the 29er with some of the benefits we used to get from 26” wheels on older bikes. While 29ers seem to continue to take over the market, there are some real benefits on the trail with a 27.5” wheel diameter.

What does a 27.5” mountain biking wheel do well?

  • Rolls over rocks and roots easier due to the wider circumference over the old school 26″.
  • More playful, nimble platform than 29er thanks to smaller wheel size and shorter chain stays.
  • Lighter overall package than the 29er.

What are the drawbacks of a 27.5”?

  • Decreased roll over – Won’t want to “plow through” roots, rocks and other obstacles as much.
  • Lately…bike choices seem to be less as there are more 29er options on the market.
mullet mountain bike - 29 and 27.5

The Mullet Bike – What is it and why would I want one?

With a Mullet Bike you are attempting to combine the best of both worlds. Up front, you run a 29” wheel and then in the rear it would be a 27.5” wheel. It takes the whole “business in the front and party in the back” theory to mountain biking by mixing the characteristics of each wheel size. We have seen a lot of these on DH circuits lately where they want the rollover of the 29er but the track is tight…so having the rear be more maneuverable was a bonus.

What do Mullet Bikes do well?

  • You get the roll over benefits of the front 29er wheel with the shorter chain stays and playfulness of the 27.5” wheel.
  • You can adjust the geometry of your bike by adding a 27.5” wheel in the rear to slightly slacken it.

What are the drawback of the Mullet Bike setup?

  • Very few bikes are designed to take full advantage of a mullet setup straight out of the box.
  • You have two different wheel sizes for buying tires/wheels.
  • Without adjustable suspension…you could actually hurt the handling of your bike.

29er vs. 27.5” vs. Mullet Bike – Which one is right for me?

I try to look at this as practical as possible so we are going to take an objective look at which wheel size you should be considering for your riding style, height and the trails you ride. As with all things, there is no right answer that fits all people. How you ride your bike and how you want it to react is the most important factor when making this decision…not what your friend bought and says is the best.

How tall are you?

As the distance from your head to the ground increases, the 29er wheel size actually becomes more proportional to your size. Riders in the 6 foot and up crowd that are looking for any mountain bike will most likely find a 29er to feel more proportional to their height. Shorter riders in the 5’6″ range and lower will need to take a serious look at geometry and test ride different frames as they might find the bike feels too big or isn’t able to maneuver as well. I have known shorter riders that have loved the bigger wheel size, but that is typically in shorter travel applications.

29ers also lengthen the bike with longer chain stays to accommodate the larger wheel size. This can create a long bike for shorter riders that might feel more comfortable on a 27.5”. The 29er can create a super stable platform on smaller bikes though. My 5’1” wife rides a 29er Trek Rail and loves it because it helps with confidence over rough terrain. She also doesn’t ride very often so the playfulness of the 27.5 would probably get lost. A test ride to get a feel of the bike and the geometry is a must for shorter riders.

  • Taller Riders: Yes on 29er 27.5” and Mullet
  • Mid Height Riders: Yes on 29er 27.5” and Mullet
  • Shorter Riders: Maybe/No on 29er; Yes on 27.5” and Mullet

How much travel are you looking for?

This factor used to have a huge impact on wheel size. However, with modern mountain biking geometry…a lot of that has changed. We are seeing the 29” wheel size on full DH race rigs so you can get any travel range you want with any of the wheel size options. Personally, I would use the height recommendations above with the travel conversation together. If you are 5.6” tall and you are going to ride a DH bike…I would really lean towards 27.5” for example.

The 29er market has also completely taken over the XC, HT or shorter travel ranges (around 120mm to 140mm). You will be hard pressed to find anything else in that range as the benefits for that riding style fit perfectly with that platform.

The interesting one here is the Mullet Bike setup. You can get longer rear travel with shorter chain stays while getting the front rollover properties of the 29er. That is why we are seeing Mullet Bikes more often in longer travel mountain bikes.

  • HT and 130mm travel and under: 29er
  • 140mm: 27.5 or 29er
  • 150mm to 160mm: 27.5” or 29er
  • 160mm+: 27.5”, 29er, Mullet Bike

What type of trails do you ride?

For me…the type of trails you ride might have the biggest impact for mountain bikers has height. As mentioned before, 29er mountain bikes do take more to maneuver through tight single track. If all of your riding is filled with tight turns in trees, you will want to try out a 29er on your own local trails before making a decision. On the other side of the spectrum, if your trails are more open and rockier, the 29er wheel size can really excel and bring more speed as you can hit sections faster.

Do a lot of racing and forest service road riding? A 29er is almost a no brainer in those situations. If you don’t believe me…just try to keep up with a 29er rider on a FSR. This adds up with the shorter travel and hard tail mountain bike market. 27.5 bikes will be no contest for a short travel 29er in these situations. If you are looking for a bike that will do a lot of things well and you ride a wide variety of trails (assuming you can only own one bike), the 29er platform might be a great “do it all” option.

  • Tight and twisty: 27.5” or Mullet Bike
  • Open and rocky: 29er or Mullet Bike
  • XC Racing and FSR: 29er

What do I personally use? 29er vs. 27.5 vs, Mullet Bike

At 6’2” tall, I am almost exclusively on 29ers these days. That said…I did ride a 27.5 Santa Cruz recently that was a blast to ride and I was really able to maneuver the bike more than my 29er. I can see applications for both and in a perfect world…I would just own them all. At my height, the 29er does feel more proportional and fits more of the trails that I ride in the backwoods of the southeast US.

What does interest me though is a Mullet Bike in longer travel situations. I can really see how that would be a blast at a place like Windrock where you need a full DH bike but you are in tight, unmarked tracks. The ability to run shorter rear chain stays with a big 29er DH fork up front might be the best of both worlds in that situation.

What is the right bike for you?

As you take a look at all of these specs, you have to look inward at your body type and riding style to see which wheel size will be the best option for you. The larger wheel diameter does have some serious advantages in certain situations, but it also does not work for others.

The best option when deciding on 29er vs 27.5 wheels…test ride your top 27.5″ candidate on your local trail and the top 29er candidate if they are available

At the end of the day, you are the one making the investment in your mountain bike and you will be the one riding it…not everyone else that is trying to inject their opinion in your buying decision. There are a lot of riders that are going to scream that one platform is better than the other. The reality is that all riders are different and that is why we have so many options. Take an honest look at how you use your bike and what body type you are. This is the only way you will get the right wheel size for you while trying to ignore the fanbois.

4 comments

CoolCmsc April 27, 2021 - 11:03 am

On a Bullit now which is 170 front and back and a Mullet out of the box.
I’m 6’ and this bike suits me and the wide range of trails I ride really well. Your point about twisty unmarked steep trails is an important one — this is where I’m getting down stuff I simply bailed on before (I’m no expert ).
Ask e-MTB, it’s easy to forget this bad boy’s weight and that’s lots of things, not least the vpp out back, but the Mullet feels a part of that.

Reply
Robb Sutton April 27, 2021 - 12:23 pm

I have been wanting to try a Bullit out since the release. It looks like a really fun bike.

Reply
Joe Crow November 5, 2020 - 11:05 am

…very interesting article – particularly the rationale for the ‘mullet bike’…

…at 5’8″ i still have my 30 year old 26″ muddy fox courier comp, which i ride occasionally, but i am fortunate enough to have been able to branch out into more modern rides: 27.5 kona precept with 120mm front/rear suspension; and 29er kona honzo al, again with 120mm front fork (both bikes bought 2nd hand for around a third of their retail value)…

…i agree entirely with the 27.5″ -v- 29er comments above, but still find the 29er an absolute blast everytime i ride it 🙂

Reply
Robb Sutton November 5, 2020 - 12:59 pm

Thanks for sharing your experience Joe!

Reply

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