Some fathers and daughters bond through listening to music or watching sports. For others, it’s through ultra-marathon cycling.

Longtime Mercer Island resident Carter Harrington, 70, with his daughter Chelsea, 27, rode in the Best Buddies Challenge, a 100-mile bike ride from Carmel to Hearst Castle. That event was on Sept. 10, a few weeks after the pair completed the 152-mile RAMROD (Ride Around Mount Rainier in One Day).

Best Buddies helps individuals with intellectual and developmental disabilities, and the Harringtons dedicate their challenge to 24-year-old Islander Brad Morse, who was born with Down Syndrome. Carter said that his passion, since retiring from a career as a commercial pilot, is helping at-risk and challenged youth.

“I have always had a special place in my heart for Brad, especially while he was in high school playing in the band. He was the main reason I attended all the home games — to see him perform in the halftime show,” Carter said.

Carter’s son Carter Quinn “CQ,” 21, is the third member of the team — “Team Badgers” — which had raised $16,725 as of press time, the 18th most of any team. This was the third time that the Harringtons participated in the Best Buddies challenge.

Chelsea graduated from Mercer Island High School in 2007, and lives in San Francisco. She said that her childhood vacations often involved biking, whether in Sunriver or Sun Valley.

“I personally really enjoy being able to do these rides with my dad. It’s a huge bonding opportunity,” Chelsea said. “I hope that I’m as fit as he is when I’m older.”

The RAMROD features about 10,000 feet of elevation gain over two mountain passes, a “challenging” course with “stunning” views, Chelsea said. Carter noted that his daughter is a “trooper,” especially because their day didn’t start smoothly.

Their car broke down on the way to Mount Rainier, about five miles from the start line. So, they started their bike ride a little earlier than the rest of the 800 cyclists.

AAA towed the car, and they hitched a ride back to the north end of Mercer Island after completing the course. Then, they rode down to the south end and jumped into the lake to celebrate.

“She was so much fun to ride with,” Carter wrote in an email to friends after the event. “She beat me up the hills. I ruled on the downhills.”

Chelsea’s love for biking started because her parents were both active, she said. When she lived in Madison, Wisconsin during college and Los Angeles after graduation, she found that biking was a good way to meet friends and explore the city.

It was Chelsea who got her dad back into cycling after a knee surgery in 2012 temporarily sidelined him.

“I pretty much hung it up,” Carter said.

His daughter’s determination brought him back into the sport, though he said he had to do a lot more training to keep up with her. He started taking spin classes in Seattle after Chelsea introduced him to the instructor, Don O’Neill of the “Ron and Don” show on KIRO radio.

Carter was an avid biker before his surgery, completing the RAMROD with friends in 1999 and 2000, along with Seattle to Portland (STP) and Seattle to Vancouver (RSVP) rides. Carter would ride with a group of eight or so Islanders in the 1990s, and they would wear matching blue and red Finlandia jerseys.

At this year’s RAMROD, Carter was one of the older cyclists, and Chelsea, one of the youngest. Chelsea borrowed one of the Carter’s former cycling group’s jerseys to match her dad.

“People could tell we were a team,” Chelsea said.

Learn more at www.bestbuddieschallenge.org/hc/support/#teambadger.