The Newton siblings behind the nationally broadcast show Mountain Bike Mania are looking forward to being seen by more of the country as they hit the season finale of their third season.

Newton South alumni Samantha and Ross McDonald co-created the show three years ago as a way to combine her television background with his passion for the sport. The only TV show dedicated solely to mountain biking, the show was picked up this year by two national cable networks – beIN Sports and American Sports Networks – and now has a potential reach of 50 million households in the country.

“The networks were looking for new sports content,” Samantha McDonald, a 2006 South High alumna, “something to supplement the big-money sports. We were doing the right thing at the right time.”

The season finale of MTB Mania can be seen on beIN Sports Tuesday at 1 a.m. EST with a re-air Wednesday at 9 a.m. EST. Footage from the show can also be seen on the YouTube channel www.youtube.com/user/mountainbikemania.

The third season was the most ambitious yet for the McDonalds as they traveled from coast to coast for 10 episodes and dealt with myriad challenges from the weather.

“This year we crisscrossed the country many times,” Samantha McDonald said, “putting 70,000 miles on Ross’s truck. We hired a different crew of 15 people for each of 10 races. Filming a series of outdoor live events is challenging, but it is always a fun adventure.

“The conditions were demanding this year,” she added. “At Killington (in Vermont), we were all on the mountain ready to film - when a dense fog descended on the trail, cutting visibility to 50 feet. Two weeks later in Windham, New York, a near-hurricane blew through and knocked out all the power on the mountain. Right after that in Snowshoe, West Virginia, a rain storm drenched our videographers and created a mud-slide for a race course.”

Samantha McDonald was a dancer and musician at South High, while 2010 graduate Ross McDonald was a track and field star who won the state title in the pole vault.

The Newton connection is felt throughout the show with 2010 South High graduate Eric Phillips creating the music and South High classmate Mara Sahleanu designing the logo.

Massachusetts native Christine Detz is the show’s producer after joining MTB Mania from the NFL Network.

“Despite the hard work,” Samantha McDonald said, “my brother and I have enjoyed the ascent. We love the creative part, and we have a great core group.”

She credited sponsors KHS Bicycles, ODI Grips, Jenson USA, and Angel Fire Bike Park for the progress of the program.

Samantha McDonald currently lives in Santa Monica, California, while Ross McDonald lives in Newton.

“For the coming season, we want to keep expanding our TV and social media audience,” she said. “Currently, we have 20,000 likes on Facebook, and 12,200 followers on Instagram. And each month we’re getting 425,000 views — on Facebook, Instagram, and YouTube.”

MTB Mania can also be found at http://mtbmania.net, https://www.facebook.com/MTBmaniaTV and https://www.instagram.com/Mtbmaniatv/.

Scott Souza can be reached at ssouza@wickedlocal.com.