As the two adventurers set out from Ryan's Shanghai home in August 2010, they hit a long traffic jam that kept them between a standstill and a 30-kilometer-per-hour pace. Their fancy riding gear was air-vented to keep them cool traveling 80 kph, but, before long, "I felt as if I was slowly boiling to death inside a damp, uncomfortable, sealed plastic bag," Ryan writes in the book. Colin, a fit sportsman, was pasty-faced with heat stroke by lunchtime, and even now says day 1 was the toughest of the whole trip.

Sixty-five days and 18,000 km later, they had made their grand loop around China. That included extremes like visiting the third-lowest point on Earth and sleeping at the base camp of Qomolangma, also known as Mount Everest in the West.

There were mudslides, suffocating heat and plunging temperatures that turned the moisture in their clothes into ice.

Everything they encountered was new to Colin, and China-veteran Ryan says the best part of the trip for him was riding along as his sibling experienced the country through fresh eyes.

"It's easy for expats to get cynical and tired and look past things that are fascinating," Ryan says. "The trip was a marvelous reminder how lucky I was, how exciting it is to be here."

The trip also re-ignited his passion for exploring China, he adds.

That passion has taken him to the western edges of the country many times since he arrived in China in 2002, and it was a special treat to introduce Colin to one of his favorite cities on Earth: Kashgar, in Xinjiang.

"My first visit there was a game-changer for me," Ryan says. "I'd never had experience with Muslim culture. Suddenly, this sheltered Canadian kid was on the border of Pakistan I was mesmerized."

When the brothers arrived at Kashgar in 2012, it was Ramadan - and the spectacle of thousands of worshippers prostrate on the ground outside Asia's largest mosque blew Colin away.

Since the ride, the brothers have written The Middle Kingdom Ride, set a Guinness World Record for the length of a motorcycle trip inside one country without doubling back, and sold the resulting TV show to an Asian broadcaster, which is airing the sixth and final episode this week. One disappointment: The series is not televised in China ("Or Canada!"), says Ryan, though he's optimistic about getting airtime later this year.

Meanwhile, the brothers have completed an India ride, which was a completely different game. "China was mostly about wide open spaces and grand solitude in many parts," Ryan says. "India was about not hitting kids or cows on the road."

While the brothers are now looking outside the Middle Kingdom for future adventures, Ryan says he's in China to stay. "My wife, and now two kids, are from Shanghai," he says. "And there's lots I still want to do here."

That includes a photography book on his beloved Kashgar and a planned TV documentary series titled Sacred Mountains, which will take Ryan to four of China's storied peaks later this year.

"That's taking me back to my roots as a photographer," he says.