For Klein, a 66-year-old Philadelphia Orchestra violinist, the 513-mile ride has combined passion and compassion. It's a testament to his love of cycling and physical fitness. It's a tribute to MS patients, particularly the late British cellist Jacqueline du Pré, regarded as one of the greatest players of the instrument, whose career was cut short by the disease. And it represents Klein's personal triumph over anxiety and self-doubt.
"What has the bike done for me?" asks this self-described "professional worrier." "Everything. It has been my savior, and made me fit to live with."
Klein has been performing with the orchestra for 40 years. Before that, he played with the Detroit Symphony Orchestra. His mother was a music teacher who put a violin in his hands when he was 31/2. For most of his adult life, he was so devoted to music that he rarely exercised.
"There was never any time," he says. "I was always hustling to one rehearsal after another."
When he and his wife, Gisela, moved to Philadelphia in the early '70s, they sometimes cycled the river-drive loop, but those rides were purely casual and recreational.
In 1986, Klein served as chairman of the orchestra members committee. He was fixer, confessor, troubleshooter, flak-catcher. "I listened to everybody's problems. It sometimes took 40 minutes to get from the stage door of the Academy [of Music] to backstage. Everybody was after me."
It was a job that required "King Solomon solutions to lots of difficult issues," a job so stressful it nearly killed him.
During one sleepless night, while walking his dog at 3 a.m., he began feeling chest pains and tingling in his arms - classic symptoms of a heart attack. He was a prime candidate - 51 years old, a smoker who drank 20 cups of coffee a day.
Luckily for Klein, the attack turned out to be more psychosomatic than cardiovascular. Nevertheless, what Klein calls "the stress crash" took its toll.
"My body was slammed so hard I was suddenly immersed in utter weakness," Klein recalls. He could barely climb a flight of stairs. He took two weeks off and spent the next two years trying to regain his equilibrium. He stopped smoking and reduced his coffee consumption. But the anxiety persisted. His doctor's prescription: exercise.
Truth to tell, Klein largely ignored that advice, again because he was too busy. Then, four years ago, while buying sheet music at a store in Ardmore, he stopped at a coffee shop, where he saw a notice about the forthcoming MS City to Shore Bike Ride.
Can I bike that far? Klein wondered.
"It scared the living daylights out of me," he recalls, "but it was also a challenge."
The following August, while the orchestra was performing in Saratoga Springs, N.Y., Klein began training. He cycled every day, pushing himself hard on the hills, learning how to ride long distance. "It's more a ballet sport than a football sport," he says, "more about spinning than grinding."
He made it to the Shore that September and has participated in every ride since, raising more than $7,000. During last year's ride, he added a loop and completed a century - 100 miles - an experience that convinced him he could tackle the Great 8. While the orchestra toured Europe this summer, he and cellist Derek Barnes rented bicycles in various cities.
Back home, he has trained with Frank Havnoonian, the owner of Drexel Hill Cycle, whom he regards as a mentor.
"Harry is very determined," Havnoonian says. "Whether he's playing the violin or riding a bike, he does everything wholeheartedly."
A few days before the big test, Klein was confident. "The big hills on West Chester Pike are getting flatter," he said. "I know I can ride 100 miles in a day."
The two most precious objects in Klein's life are probably the 329-year-old Ruggeri violin he is privileged to play, and his 18-month-old Raleigh carbon-fiber bike. While music feeds his soul, cycling has brought changes to his body (he's 20 pounds lighter, at 146 pounds) and mind.
"We musicians can be difficult to live with because we insist on such exactitude," says Klein, who raised more than $10,000 for MS through the Great 8 ride. "Because of cycling, I'm more at peace with myself, and that's enriched my playing.
"To me, the bow is like a brush with which I paint an audio picture. Cycling has made me more relaxed and given me so much more energy that I can put directly into the music."
Contact staff writer Art Carey at 215-854-5606 or email@example.com. Read his recent "Well Being" columns at www.philly.com/wellbeing.