Mountain bikes have made quite an evolution since the first knobby tires were ridden down Mt. Tam in the early 1970’s.
From steel frames with no suspension and drum brakes to today’s long-travel carbon frames with electronic shifting and hydraulic disc brakes, the equipment and the sport has come a long way.
With the design evolution of the modern mountain bike, one of the biggest changes has been the wheel size.
Where once mountain biking was just a 26-inch wheel game, now the majority of bikes are 27.5, 29, or…gasp! One size wheel for the front, and another for the rear.
This begs the question of course, “Which mountain bike wheel size is right for me?”
The reality is, there are a lot of factors that go into determining which wheel size is right for you. I’ll use my personal situation at home to illustrate my point.
I have what you would call a “cycling family.”
Let’s start with me, Joel. I’m 51-years-old, 6 foot 3, and have been riding and racing pretty consistently since I was in high school.
Then there’s my wife Carrie, who is in her mid-40s, 5 foot 7, and who raced when she was younger, who now rides 4-5 times a week and still goes pretty fast.
Next we have my daughter Evie, who is 14-years-old this year. She just surpassed my wife in height, and does the family ride thing 3 days a week on most weeks.
Last we have my son Ethan, a 12-year-old who stands about 5 foot 2. He’s strong and loves to fearlessly descend. He generally hates climbing, but the rougher the trail (regardless of up or down), the faster he goes.
Let’s start backwards from my son.
Ethan rides a 27.5-inch wheel bike. He’s strong and has decent bike handling skills. But the reality is, a 29er bike is just too much bike for him.
He’s too short for the big wheels, and the bike handles too slowly for him to make quick adjustments to go over and avoid obstacles.
He also likes the playfulness of 27.5-inch wheels — the quick acceleration of the wheels, and how he feels “in” the bike rather than “on top” of the bike (a common complaint for riders of short stature on 29 wheels).
All that said, there is (of course) an exception.
Last year, we rode a bike park together. There was a lot of very fast, rough, open terrain.
Watching him descend in front of me, occasionally getting some head shake and bar swap, I couldn’t help but think it would have been advantageous if he had the stability and wheelbase of a 29er bike.
He’s not there yet, but I know it’s coming.
My daughter Evie recently transitioned from a 27.5-inch wheel bike to a 29er after a 5-inch growth spurt. But the quick height change was only part of the reason for the change to a 29er.
Evie’s riding style is very much complimented by the bigger 29-inch wheels. She is super smooth in every way, and values stability over almost every other factor.
On climbs, where my son chops at the pedals with every stroke, my daughter keeps a very consistent cadence: no matter what speed she is going, her legs are moving the same speed.
It’s the same on the descents. She can be going five miles an hour or she can be riding 20 miles an hour: her body is planted in the middle of the bike, and there are no quick actions happening at the handlebars. She just floats through the dirt in every condition.
The 29er is a perfect fit.
My wife Carrie has an incredible amount of experience riding bikes, all the way back from the early days of 26-inch wheels up to today’s “modern” bikes. She’s tall enough to ride a 29er, and would certainly benefit from the roll-over capabilities of the 29-inch wheels.
But…she’s bothered by the slower handling of the big wheels, both in terms of acceleration and turning. She wants something she can move around underneath her easily, and also get up to speed quickly if she wants to power up over rough terrain.
As you can imagine, the perfect bike for her is a mixed wheel bike, like the nine7five. She rides fast enough downhill to appreciate the 29er’s enhanced traction, but can still pivot off the smaller 27.5-inch wheel or accelerate quickly to get the bike moving.
There is also a playfulness that the smaller rear wheel adds that makes a nine7five more enjoyable for her to ride (versus a straight 29).
And lastly…myself. There’s just no denying a 29er for someone of my size, strength and riding level. I’m pretty aggressive on downhills, but ride smooth lines while doing it, so I love the stability and added traction of the 29er.
I also mostly ride in a big gear with a lower cadence and power up climbs. It’s no problem turning over the big wheels, and with my larger stature, I don’t have problems changing the direction of the bike.
If I am going to ride DH, I would ride a 29er. If I raced XC, of course, a 29er. If the terrain iss tight and techy…a 29er. I would call myself the perfect candidate for 29-inch wheels.
So then, to go back to the question: Which mountain bike wheel size is right for you?
I would start by saying that all mountain bikes are really personal. I have friends who are my size who swear by 27.5-inch wheel bikes. At the same time, there are World Cup XC racers who are the same height as my son who would not consider anything but 29 wheels. A big part of it is just preference.
That said, I think there are some guidelines to get the process started to figuring our your optimal wheel size:
- If you’re under 5 foot 2 or riding slower, more technical terrain, try to get a demo on a 27.5 bike.
- If you’re 6 foot or above, you will likely prefer a 29er bike.
- If you’re either of those categories or anything in between, you have to try a mullet bike (29 front/27.5 rear). There is no denying the performance and fun factor of bikes like the nine7five.
Mixed wheel bikes (or mullet bikes) have been making big waves in the mountain bike world this year. More riders are winning races on these bikes. And with features like quicker handling, faster acceleration, and the combined benefits of a 29er and a 27.5 wheel, it makes sense that these hybrids are gaining the level of attention they’ve got coming at them.