For years, Stuart Hargreaves has participated in Group Health’s annual Seattle to Portland (STP) ride.

The Redmond resident has done the ride a few times on his own, but last year, for the first time, his 12-year-old daughter Lili — who was 11 at the time — joined him. The two did the 205-mile ride on a two-person tandem bicycle.

“I liked it,” Lili said.

She and her father were riding to raise money and awareness for cystic fibrosis (CF) research through the Cystic Fibrosis Foundation (CFF).

This weekend, they will be joined by Lili’s younger sister, 11-year-old Amelia. Again, the Hargreaves family will be riding for the same cause, which is near and dear to them as Lili was diagnosed with CF when she was 3 years old.

Stuart said at that time, they had just moved up to Redmond from Portland. Lili was hospitalized for pneumonia and it was during this period that her doctor figured out what her symptoms — which mainly manifested as decreased lung function — meant.

As a result of this decreased lung function, Stuart said Lili and others with CF are prone to lung infections as they are not always able to expel the bacteria that may collect in their lungs. In addition, he said Lili has to take an enzyme-replacement supplement to help her body break down fat and digest food.

Anybody wishing to support Team Lili and the CFF can do so by making a donation to a team member at the CF Cycle For Life site at fightcf.cff.org/goto/TeamLili.

The Hargreaves family will also be posting updates of their two-day bike ride (participants can either finish the ride in one or two days) on Facebook at facebook.com/goTeamLili.

Although Lili has been living with CF for most of her life, she has not let that stop her from being active. She said it actually probably helps with the CF, but it is difficult to tell.

Stuart agreed that physical activities such as bicycling help her use her lungs.

His wife Sarah Hargreaves added that as long as Lili is healthy and exercises regularly, her lung function remains normal.

To prepare for this weekend’s ride, Stuart and his daughters have been doing local rides since late February. Their most recent ride was around Lake Washington, which is about 60 miles. They have also ridden along the Sammamish River Trail and Burke-Gilman Trail to the University of Washington. The three have also participated in the Alaska Airlines Flying Wheels Summer Century 67-mile ride.

For these rides, they use a triple tandem bike. Stuart said he has named the bike the Tween Machine in reference to his daughters’ ages. However, Lili and Amelia do not like the name for that same reason.

As a one-car family, Stuart said the Tween Machine is also their second car and they use it to run errands such as going to the store or dropping the girls off at school.

Lili said it’s fun for them to go places together on the bike.

Amelia added that bicycling is economical since they don’t have to pay for gas, which also makes it environmentally friendly as it doesn’t cause pollution. She said she likes cycling because you’re exercising while on the way to your destination — something you can’t do in a car.

Stuart said riding with his daughters is great. He said it makes him happy that they want to ride their bikes together.

“I like that they’re doing an activity as sisters,” Stuart said.