"When I was a kid, no one showed me how to fix a bike," he says. "My mom never took me to a bike shop because we grew up low income, so everything I had to learn from scratch."

Rangel makes a point of showing those skills to the kids and parents lingering by their bikes. He wants young people and adults, especially in working-class neighborhoods like southeast Fresno, to be able to bike more to fend off chronic illnesses such as diabetes.

Rangel speaks from personal experience.

Facing Type 2 Diabetes as a Teen

Rangel was just 14 and living with his family in Los Angeles when he was diagnosed with Type 2 diabetes. Obesity and a sedentary lifestyle are risk factors for the illness. While he was tall -- 6-foot-1 -- he weighed 260 pounds.

It's been a dozen years since he was diagnosed, but he clearly recalls how frightened he was. The disease had already transformed the lives of his mother, two sets of grandparents and other relatives. He knew what he was facing.

"I was really scared," says Rangel. "I was seeing there were only certain foods they would eat, taking their insulin shots. And I was like, 'Nah, that can't happen. I'm too young!'"

Until about two decades ago, Type 2 diabetes in children and teens was practically unheard of. But the number of adolescents living with the disease has gone up in recent years, in large part because of the obesity epidemic.

As with adults, rates of Type 2 diabetes are higher among Hispanic, African-American and Asian-Pacific Islander youth than non-Hispanic whites, according to data from the Centers for Disease Control and Prevention. Uncontrolled diabetes can lead to blindness, heart disease, amputations, kidney failure and other serious complications.

Rangel's doctor had said he needed to lose weight and give up foods he loved. But he didn't know how to start. He loved the idea of biking, but his family couldn't afford to buy him one.

Instead, a close friend stepped in with a gift of a BMX bike. He didn't know how to ride and at first it was scary. He fell a lot the first couple of times he tried.

"I was a big dude riding a really small bike, so I didn’t know how to balance my weight," Rangel says. "But I just kept going. I didn’t want to stop, and I just kept doing it so I could get better."

With each trip he took, he ventured longer distances. Rangel says he enjoyed the independence he felt while crossing large swaths of the traffic-jammed city. Under the power of his own legs pushing down on his bike's pedals, he would travel from his home in the Lincoln Heights neighborhood to the beach at Santa Monica -- 20 miles away.

Within a year, Rangel had reversed his Type 2 diabetes. His blood sugar levels returned to a normal range. It's surprising to many, but children and young adults can beat the disease through exercise, say medical experts.

The experience marked Rangel deeply. He had managed to rid himself of the illness without taking medication while having fun, too.

"Biking changed my life. I lost a lot of weight," says Rangel, who now weighs about 220 pounds.

Rangel's family noticed the change in the way he looked and the dramatic improvement in his health. At Rangel's insistence, his mom, cousins and uncles began biking -- a dramatic change for his family, he says.

"We all got rid of our diabetes, pretty much," says Rangel, who recently moved to Fresno. "Now when I'm in L.A., about 20 of us go bike riding together. So it changed not just me, but my whole family at the same time."

Rangel wants to promote biking and a more active lifestyle to create positive change in his new home in Fresno. The most recent state data show the county had the fourth-highest death rate from diabetes. Central Valley counties Kern and Kings also top the list.

Using his personal experience and love for biking as a mantra, Rangel coordinates youth engagement for the San Joaquin Valley Latino Environmental Advancement & Policy Project and manages the group's Bici Projects (short for "bicicleta" -- bicycle in Spanish).

How Can Type 2 Diabetes Disappear?

Type 2 diabetes is an illness affecting a person's ability to use insulin, and not everyone can beat the disease through exercise and weight loss. But there's "tremendous hope" for young people and others diagnosed with the disease early on, says Dr. Saleh Adi, medical director of the Madison Clinic for Pediatric Diabetes at UCSF.

Insulin is a hormone that allows the body to use sugars from carbohydrates. Patients with Type 1 diabetes, an irreversible autoimmune disorder, must take insulin medication for life because their bodies are no longer able to produce it.

In contrast, people with Type 2 diabetes are still able to make insulin for the most part, but their bodies don't respond to it properly, and they develop what's called insulin resistance. Exercise can change that because active muscle "is the biggest site of insulin action," says Adi.

"Exercising increases your sensitivity to insulin, and that’s true in everybody," says Adi, whose pediatric clinic tries to get patients to engage in physical activity for six months before prescribing them medication.

"We've seen quite a few cases where the disease disappears," he says. "If you catch it early enough and do what it takes, which is exercising and losing the weight."

Adi readily acknowledges squeezing more exercise into daily routines is not easy, but he says even 10 more minutes of walking can begin to make a difference.