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29er vs 27.5er

The choice of mountain bike wheel diameter has always been a controversial issue, and today, in 2020, 29er wheels are becoming more and more popular among all strength models, and Mullet Bike (a hybrid wheel diameter model, 279, 29er front wheel and 27.5er rear wheel) is getting more and more attention from manufacturers. What can we bring and what can we lose with bigger and bigger wheel diameters, what is the role of Mullet Bike and will it be the future trend? Let’s enter today’s Into Science ……

Sorry for the crosstalk, back to the topic, in 2014, 27.5er wheel diameter models are fully popular, 26er gradually fell, in 2020, 29er wheel diameter seems to be the history will be repeated. In the past, only XC models everywhere 29er, some Trai, AM models occasionally some manufacturers will also use with.
As time went on, more and more 29er big-travel mountain bikes were introduced, and in 2017, 29er speedway also appeared on the World Cup circuit. There are hardly any 27.5er models involved in pro racing now, and many manufacturers have eliminated some of their 27.5er models.
As we have said in the past, everything in mountain biking has changed to get faster. So what exactly is the “magic” of the 29er?

We are different
Let’s take a look at what’s so different about the 29er versus the 27.5er that the 29er phased out the 27.5er (we’ll discuss the regular wheel diameter first, Mullet Bike will do so later).

1. Passability

Mountain bikes face a track full of technical points, passability is an important performance, wheel diameter is the key factor affecting this performance. The larger the wheel diameter, the better the passability. Before explaining why, the author needs to introduce a concept – angle of attack.
The angle of attack refers to the angle formed between the contact point of the wheel set and the touch point of the obstacle. The smaller the angle of attack, the better the passability. 29er’s angle of attack is less than 27.5er so 29er has better passability.
What is the impact of this in the actual riding experience? It’s simple, it can be easier and more relaxed when facing technical points like rocks and roots.
As an example, Aaron Gwin rode a 27.5er yt tues at the 2018 Speedway World Cup in La Bresee. the front wheel got stuck in a pothole and flipped over, with riders joking that UCI had plowed a 28-inch pothole in the track so Aaron Gwin could change to a 29er speedway.
This is a joke, but it also shows from the side that the passability brought by the 29er is a very important improvement.

2. Speed maintenance ability, acceleration ability

This characteristic is determined by the weight distribution and rotating mass of the wheelset. 27.5erer has better acceleration but less speed maintenance, while 29er has less acceleration and more speed maintenance.
The 27.5er wheelset has a lower rotating mass and higher acceleration due to the weight of the outer tire, rim and spokes being off the axle and the relatively lighter weight of the outer tire, rim and spokes, resulting in better acceleration but less speed retention.
The 29er is the opposite. It can be compared to the high frame and low frame wheelsets on road bikes, 27.5er is the low frame and 29er is the high frame. (I replaced the 29er enduro after the most intuitive is the speed retention ability, after the speed reached a higher range, 29er speed will be much faster than the 27.5er, I even want 220mm brake discs to brake)

3. Handling

In this regard, there is no doubt that the 27.5er is more flexible, 29er especially in dealing with sharp curves and bends in the road slightly clumsy.

After looking at the difference between the regular wheel diameter, we will look at the Mullet Bike, which is a product of the race course, after UCI released the restrictions on mixed wheel diameter models, Mullet Bike immediately became popular in the race course.
Once a big fan of the 27.5er (Bruni said he hated the 29er when it first hit the track in the 2017 season), Bruni, a triple World Champion, said the Mullet Bike “smells good”. He won two World Cups and the World Championships in his first 279 downhill of the 2019 season.
The “magic” of the Mullet Bike is that the front wheel with the 29er rear wheel uses a 27.5 mix of wheel diameters to combine the advantages of both diameters. 29er front wheels have great passing and cruising performance, while 27.5er rear wheels have great acceleration feedback and agility. The 279 seems to be a perfect match, i.e. very high passability without losing agility.

What PROs and manufacturers think and how the 29er actually performs

XC racing has long been popular 29er, so we will put it aside, EWS because the race system is more complex, and most of the domestic enthusiasts understand than not much, so this part of the DH World Cup as an example.

2017 season
The first station of the 2017 season speedway World Cup in Lourdes, Greg Miner’s prototype test 29er v10cc marked the official entry of 29er speedway into the World Cup race. At Fort William, Greg Miner took the win on his 29er v10, the first win for 29er speedway.
Fort William is a must-ride course for the Speedway World Cup, and the boulders of the Scottish Highlands have made the world’s top riders taste the pain, and many top riders have suffered here.
But this is also like the blessed land of 29er speedway. 29er speedway first victory was born here, 2018, 2019 Amory Pirrand rode commencal supreme dh29 to win the men’s elite category for two consecutive years here, 2019 Rachel Atherton also took the championship with her own 29 speedway.

2018 season
29er in speedway also tends to mature, supporting geometry system is also gradually being established, 29er speedway becomes more and more excellent. Of course some pro’s are still a bit dissatisfied with the current model, and some don’t think the 29er is right for them (the Bruni mentioned above is).

The 29er speedway parts line has been gradually improved, and more and more 29er speedway models have come into being, with brands such as Trek, Scott, Mondarker, Pivot, Commencal and others launching 29er models one after another. Riders aside, at least the brands are happy to launch 29er models, and the new big wheel models will be a great tool to boost the sales of traditional mountain bikes.

2019 Season
Almost every brand has a 29er speedway chariot, and riders are more than happy to choose a 29er speedway. At the same time, almost all manufacturers have further optimized their geometry, which, in addition to improving flexibility, has given the 29 a wider audience and lowered the height threshold for 29er speedway.

In the 2019 season, with UCI opening up the rules of mixed wheel diameter, mullet bike 279 wheel diameter also appeared in the World Cup race. Gradually gain riders favor, Bruni as 279 advocates also lived up to the expectations of taking three victories, including the World Championships. Of course at this time the 279 model, mostly between the 29er models to achieve.

2020 season
For some well-known reasons, this year’s speedway season has only just begun, the World Cup race is still for the opening.

But this will not affect, manufacturers push the new. 279 speedway models were officially launched, geometry and other aspects have been optimized, the two most representative models are Commencal Superme dh and Specialized DEMO.

Where do we go from here?

“The 29er is really good, but not necessary, but if you have the opportunity to change” (except XC models, because now XC no one will use the 27.5er), at least we think so (only personal opinion). 29er mountain bike, indeed, we can become faster.
For me personally, after replacing the 29er enduro, I can feel the speed in the track obviously. Especially in the straight road and the track full of rocks, roots and other technical points.

In other words, the 29er can improve the “technology” with the same technical level. Because in addition to faster speed, 29er can help riders face obstacles, technical points and drop-offs more easily.

Also, thanks to the evolution of modern mountain bike geometry, height, a factor that previously limited the development of the 29er, is almost non-existent. For example, Sina, the 2019 XC MTB U23 Women’s World Champion, is only 151cm tall, but she is still using a 29er bike.

Also thanks to the development of geometry, the “bulky” situation of 29er models in the past has been improved.

At the same time, 29er has become an unstoppable trend, leaving less and less room for 27.5er in the future (new products, used warranties, etc.).

But 29er will not be suitable for every individual, such as action riders and “fun” riders. 29er is a pure competition machine, it is only for fast. Relatively speaking, it will be less fun and more “silly fast”, and the 29er will bring some hindrance when playing some action or “fancy operation”.

By the way, about mullet bike279, this type of model is the future of the race track and manufacturers to plow the new world, is also very worth trying.
However, I would like to say that the mullet bike279 will be set up more towards the competition, handling it to play the proper performance will require more advanced skills of the rider.
Of course, compared to the need to replace the 27.5er frame, wheelset, fork to achieve the 29er, mullet bike279 is easier to achieve, for those who want to upgrade the bike is also a good choice.