Does size really matter? If we’re talking mountain bike wheels, my answer is, it depends. I’ve had the luxury of riding a few different 29ers and 27.5s with varying travel sizes and geometries. I like them both. Currently, my main weapon for cross country is the Scott Spark (29er and 27.5). For enduro/trail riding it’s the Scott Genius (27.5).
If we haven’t met on the Internet or in person yet, I’ll give you a quick introduction so you’re not wondering, who is this person who is talking about wheels and what is her background? I’ve been a pro ultra-endurance racer for seven years, and just this past season started racing enduros. Although I’m the 2015 World 24-hour solo champion, I primarily focus on XC stage races and 100 milers. Follow me on social media if you ever want to follow along. Bottom line, I spend a lot of hours on two wheels on all different terrain across the globe, and have won races on both wheel sizes. So which do I like best? It’s complicated…
I solely rode 29ers for years because at the time my bike sponsor only offered 29ers. But in the last couple years, the brands I’ve been associated with have offered a variety of bike choices.
As someone who had been on a 29er for a long time, I admit I was skeptical as to whether I’d like 27.5. The truth is after riding both options I love both wheels sizes. They feel really different. For reference, I’m 5’7”, and while I’ve heard arguments that smaller riders may prefer smaller wheel sizes, I’ve seen plenty of very small women rip it up on 29ers.
That said, I think it all boils down to the terrain you are primarily riding. I lived in Colorado for nearly a decade and rode thousands of miles on trails around the Southwest. Most of those trails weren’t particularly twisty or crazy technical. Honestly, I didn’t know what crazy technical meant until I moved to British Columbia. My opinion of wheel size and even the way I set up my bikes completely changed.
So what’s the answer to this ever-lasting debate?
I prefer a 29er when…
Wagon wheel bikes are like a luxury automobile. I like them when the terrain is fast and flowy, without a lot of sharp turns. They are also perfect for dirt road riding (for say, a Leadville 100) and for a lot of the stage races I do. I also find that 29ers are nice on loose or slippery terrain because there is a bigger rubber footprint on the ground. If your speed is high, a 29er will plow through obstacles better than a 27.5.
However, once you get hung up on something, it’s more challenging to get going again, as the acceleration of a 29” wheel is slower than a 27.5” simply due to mass. Also a lot of 29ers have a steeper head tube angle than a 27.5, which makes it a little more business and a little less party.
I prefer 27.5 when…
The tweener wheel size is like driving a performance-tuned sports car. I prefer them when the terrain is technical and when I want a playful, responsive feel. Often technical trails are slower paced than their flowy counterparts. In other words, there’s a lot of low-speed handling. I prefer 27.5s for technical trails because it’s easy for me to keep get the wheels moving on punchy spots, rocky, or rooty terrain, or on steep climbs. It’s also easier for me to throw the bike around and use obstacles on trails to gain speed rather than plow through them.
Bikes with 27.5 wheels also have a shorter wheelbase. That said, at high speeds, the 27.5 can feel twitchy compared to the 29ers and don’t carry momentum as well through fast sections. Bottom line, 27.5 is my go-to wheel size in British Columbia, and what I’m primarily riding on a daily basis. But when I go back to most places in the Southwest, I pull out the 29er.
If you are riding varied terrain that isn’t overly technical or steep, the 29er will be a nice ride. If you tend to be more aggressive and like steep, technical terrain, the 27.5 is my pick.
If you’re shopping for a bike, I suggest you demo both wheel sizes and decide for yourself. No matter what wheel size you ride, it’s going to be fun. I’d love to hear what your preferences are and why, so leave a comment below.