29ers Are Faster than 26ers, Study Finds

Photo credit: Media Platforms Design Team
Photo credit: Media Platforms Design Team

Wheel size is a source of endless debate in the off-road racing world. Conventional wisdom has held that larger wheels (aka 29ers) rule for rolling over rough surfaces, long straightaways, downhills, and wide sweeping turns, while smaller hoops (26ers) are superior for tight, twisty trails and uphills. To put the debate to rest, Swiss researchers cobbled together a three-quarter mile course with equal measures of both types of terrain.

Ten cyclists (seven male, three female) from the Swiss National Cross Country team race the course six times—three times on 26-inch bikes and three times on 29-inch bikes—while the researchers timed them and tracked power, heart rate, and cadence metrics. The riders were also asked to report their general impressions of each bike.

In the end, the 29ers came in 7.5 seconds ahead of the 26ers—a 2.4-percent speed increase—without making the riders work harder, as there were no differences in power output, cadence, time spent coasting, work, or heart rate. Interestingly, 29ers were faster in the sections they were “supposed” to be faster on, as well as the sections thought to be better suited for smaller wheels; the riders also reported they felt the 29ers handled the course best. And in racing, 7.5 seconds is certainly a significant margin for winning a race, which was the point of the study.

What the study misses, of course, is the new hot wheel size—27.5—that has all but replaced 26-inch wheels, especially in the US. This isn’t due to oversight on the researchers’ part: Science simply moves more slowly than the bike industry swaps specs. “The study was conducted in December 2011 before the Olympics in London, and at this point in time, no 27.5 bike was available,” says study author and sport scientist Thomas Steiner, PhD. Those bikes came after the fact, when Steiner learned that Swiss World and National champion mountain bike racer Nino Schurter was planning to race a custom-built 27.5 for the Olympics.

So the most relevant wheel size debate is still ongoing—though Steiner speculates that 29ers are likely still faster than 27.5 bikes, which would be close contenders in a similar head to head comparison. “Only one top athlete from Switzerland—Nino—is using a 27.5 bike at the moment,” Steiner says. “All others are riding 29-inch bikes. I would suppose that the 27.5-inch bike is in between the two others, but closer to the 29-inch bike, since wheel circumference is closer to the 29-inch wheel.”

Our verdict? Unless your livelihood comes down to crossing the finish line seconds ahead of everyone else, ride the wheel size that feels best for how and where you ride.

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