"Yes, that's me," Tierney said.
Wearing a bike helmet and riding gear, he might appear like the legions of bike enthusiasts who take to Colorado pavement when they can. But what makes the Aspen resident so unusual is that when he rides, he does it on one wheel, choosing to perch high atop a unicycle.
"For me it brings just sort of state of the now nirvana type feeling," Tierney said.
That makes riding hard enough, but Tierney added another level by riding his unicycle up and over the highest mountain passes in Colorado.
"This summer I was able to finish every pass that crossed the Continental Divide in the State of Colorado. There were 28 of them," Tierney said.
It is a challenge that helped get him ready for his biggest ride yet when he set a world record by becoming the first person to ride up Mount Mauna Kea in Hawaii. He went from sea level to the top of the mountain passing jungle and lava flow along the 13,780-vertical-foot climb.
"I had just so many emotions running through me at the very top," Tierney said.
To understand what kind of achievement that is, you have to understand what it's like to ride a unicycle, or even what it's like to just get on one. For most people, that's just about impossible to do, let alone ride it for 40 miles.
"It's not easy to learn and that's why you probably don't see everyone doing it," Tierney said.
It's believed the unicycle started rolling in the late 1800s as an offshoot of the big wheeled penny-farthing bikes, when riders found they could just ride on the front wheel. Eventually two wheels would spin into popularity and unicycles got pushed to performers and acrobats.
But in recent years they have come full circle thanks to growing number of unicycle enthusiasts like Tierney.
"They now make them so they don't break, so you can go off road, you can go on road - they are solid and reliable," Tierney said.
Not that unicycles have become mainstream; they're still rare enough that when Tierney rides, he finds people pulling over to cheer him on, shake his hand or take his picture. It's with good reason: the man set a world record and takes down mountain passes on a unicycle.
"One wheel just makes it that much sweeter," Tierney said.
He also works as a ski patroller and during the ski season often rides his unicycle down the snow covered slopes. He has also taken his unicycle in bike race events including the Iron Horse Classic and the Copper Triangle.
(KUSA-TV © 2011 Multimedia Holdings Corporation)