When Tyler Wren was growing up in the suburbs of Philadelphia, he would always watch the big pro bike race in June.

"I thought the cyclists were impossibly fast," he recalls.

On Sunday, Wren himself will be one of those "impossibly fast" cyclists, scaling the Manayunk Wall and sprinting down the Parkway, as he competes in the TD Bank Philadelphia International Championship.

With a field of elite cyclists from around the world, the 156-mile endurance test, now in its 26th year, is the longest-running, most prestigious single-day cycling road race in the United States. For Philadelphians, it's a highlight of the summer calendar and an excuse for a citywide block party.

For Wren, 29, who rides professionally for the top-ranked Jamis/Sutter Home pro men's cycling team presented by Colavita, the race is a favorite, and a chance to show off before a hometown crowd.

"Family and friends will be watching," says Wren. "This is a good opportunity to show them what I'm doing with my life."

It's an unusual career path for someone with Wren's resume. Wren, also known as "The Wrenegade" and "The Sniper," is an alumnus of the Episcopal Academy and Princeton University. While many of his classmates are climbing the ladder in law firms and brokerage houses, Wren has ascended the ranks in a very different kind of pursuit.

He is among the top 15 riders in the United States and has made a name for himself as a breakaway specialist. But the requirements of his profession are rigorous: traveling half the year, racing 70 to 80 times, training 400 to 700 miles a week.

"I still like the lifestyle," says the personable Wren. "It feels so good to be fit."

Endurance athletes tend to peak in their late 20s and early 30s, which puts Wren in the middle of his prime.

Intrigued by Wren's Ivy League background and collegiate cycling success, John Profaci, director of marketing for olive-oil distributor Colavita, the team's presenting sponsor, invited him to join what was then the Colavita team in 2003. "This is not a lucrative way to make a living. He's really following a dream." (Pro cyclists earn from $30,000 to $100,000 a year, Profaci says, which includes base salary and winnings. Wren falls somewhere in the middle of that range, he says.)

Sebastian Alexandre, the team's directeur or coach, calls Wren "a very good climber. He has a strong heart and is a good fighter."

In flat races and sprints, Wren is often a "domestique," a rider who sacrifices for the team, protecting and advancing the leader. In hilly and longer races, especially multi-stage and multiday events, Wren may be the leader himself.

"The real challenge is preparing for different distances," Wren says. He compares pro cycling to "a combination of chess, NASCAR, and the X Games."

His body is ideal for the sport. At 5-11, 143 pounds, he is so lean that his body fat registers in single digits. From the knees down, his legs are spindly, but his thighs are muscular and relatively massive.

During Sunday's race, he expects to burn 10,000 calories. He will need to consume an energy bar every half hour, 20 bottles of water, a dozen energy gel packs.

His most potent tool, however, is between his ears. "It's all about whoever can suffer the most," he says. He fondly quotes Henry Wadsworth Longfellow: "Know how sublime a thing it is to suffer and be strong."

Until relocating to Salt Lake City in the fall, Wren lived for five years in Fairmount, where he also spent the first seven years of his life.

His family later moved to Wynnewood, then to Rosemont. Wren was "a lifer" at Episcopal, spending 14 years there. As a teenager, he attacked trails on a mountain bike on weekends, often participating in races with his father, a lawyer. (His mother, Missy, is a former professional ballerina with the Pennsylvania Ballet.)

In high school, he excelled in running. As a sophomore, he won the Inter-Ac cross-country championship. As a junior, he ran track, setting the school record for the mile, 4 minutes, 28 seconds. As a senior, he was captain of three teams - cross-country, wrestling (he won more than 100 matches), and track, earning all-Inter-Ac honors in each.

Crawford Hill, an Episcopal biology teacher and former wrestling coach, calls Wren "a cardiovascular machine" and "a force of nature."

"He might not have been the most technically savvy wrestler, but he was so tough he just kept coming at you the whole six minutes," Hill says.

The summer before his freshman year at Princeton, Wren was plagued with running injuries. To give his battered body a rest, he bought a road bike and joined the cycling club. His first jaunt with the group was inauspicious. At a stop just a mile from campus, he crashed into the team captain.

Wren begged forgiveness and persisted.

"I quickly discovered I had a passion for the sport," he says. And a talent. In the spring of his sophomore year, he won the national collegiate cycling championship. He placed second his junior year, third his senior year.

After graduating with a degree in economics, he shunned business school to join the Colavita cycling team.

"I thought it was a home run, getting someone like him," says team sponsor Profaci. "Tyler is the glue. There's always animosity on a cycling team, but Tyler gets along with everyone. Teamwork is essential to success, and Tyler has really kept the team together."

At the end of the racing season a couple of years ago, Wren was tempted to quit. He had applied to business schools and been accepted by several. But the lure of the strenuous life he had pursued since college held.

"Right now, I'm taking it year by year. The travel is hard, and the sheer number of races makes it difficult to stay focused and hungry. Sometimes, it starts to become a haze; there's so much suffering you forget what's going on."

His goal Sunday is to be in the lead pack at the finish and to avoid a repetition of his first Philly race, in 2003. On the seventh lap, as he was sprinting down Main Street in Manayunk, his chain came off. Wren went flying, hitting his head on the pavement with such force that he destroyed his helmet and sustained a concussion that erased his memory.

"The whole goal was to have that experience," he says, "and because of the crash, I couldn't remember a thing. It was a real disappointment."

Contact Art Carey at 215-854-5606 or acarey@phillynews.com.