Tricycles aren't exactly the mode of transportation often associated with high-speed, adrenaline pumping acts of extreme sports showmanship. But a group of men hailing from Oakdale calling themselves the "Drift Trike Mafia" are looking to change all that.

Their video-documented exploits posted on YouTube have been viewed more than 300,000 times since June, and they certainly caught the attention of Tuolumne County officials and law enforcement last Monday after hurtling down Old Priest Grade Road near Groveland on their custom-made tricycles.

Early reports from California Highway Patrol stated a group of men riding "three-wheeled coasting devices" - then believed to be "street-luge boards" -illegally closed off the extremely steep road Monday between 2:30 and 3 p.m. for a quick downhill run.

But the Drift Trike Mafia wanted to set the record straight and let the public know they mean no harm.

"It's quite the adrenaline rush and that's why we do it," said Will Valverde, 24, one of the group's founding members. "But we're not looking to get hurt or hurt anyone else in the process,"

The tricycle drifting crew, with a core membership of six riders, also denied allegations they closed the road Monday, claiming Caltrans maintenance workers actually put up the blockade.

Any closure of Old Priest Grade Road is under the county's jurisdiction, but Caltrans maintenance workers were in the area around the same time repainting a stop bar line in the road, said the transportation agency's spokeswoman Angela DaPrato on Thursday.

"Prior to the Drift Trike Mafia coming down, Caltrans was already done and not on Old Priest Grade," she said.

The Drift Trike Mafia formed early this year after friends Valverde and Austin Sprague, 28, stumbled upon the sport while surfing the Internet. Since then, Sprague and Valverde estimate they've "drifted" more than 200 miles of road on their trikes.

Each of the group's trikes are made mostly with repurposed bicycle parts and feature a rubber front tire, front brakes and two dolly wheels wrapped in 10 inches of PVC pipe that aid "drifting" - where the rider intentionally oversteers and causes the rear wheels to lose traction.

Using their hips to "drift" the tricycle from side to side helps to slow the trike down - somewhat similar to a snowboarder carving - while zipping down steep hills.

"It's a hobby, everyone has a hobby," said Valverde, who owns a shop that customizes party buses. "People ride bikes, people ride skateboards, and this is just something we found that we all like to do and keeps us out of trouble."

In June, the group posted a video of themselves riding down Old Priest Grade, which has a slope of 22 percent in places, and within days it was viewed more than 10,000 times.

"When we hit 10,000 I thought I could die happy if we got to 25,000," Sprague said.

Within another week, the video had already topped Sprague's goal and was cruising to hitting 100,000 views. It has been viewed 345,230 times as of Thursday evening.

Sonora-area CHP Commander Lt. Scott Clamp watched the video recently and said there are some "clear violations" committed when riders are shown crossing the double yellow lines into the lane of oncoming traffic, but there's ultimately little that patrol officers can do when the riders do obey the traffic laws.

"The CHP's take on the whole situation is that pedestrians are allowed on that roadway, whether it be on trikes, skateboards, bicycles, or whatever mode of transportation," he said. "But there are right-of-way violations they need to know about."

CHP has been concerned in recent weeks by not only tricyclists on Old Priest Grade, but also skateboarders. A video posted on the web last month depicts an unidentified man on a skateboard winding his way to the bottom of the road at breakneck speeds.

That video has since been viewed online more than 15,000 times and made headlines across the state.

"I would discourage them from that general area of the road just because there's no shoulders and no place for them to safely ride," Clamp said. "They are legally entitled to be in the road in certain areas. But as far as safety goes, it's not a very safe idea at all."

Trike drifting has gained popularity over the past decade, after first making waves in New Zealand, according to John Georgilis, of the American Drift Trike Association. He said other countries where the sport has taken off includeAustralia, Portugal, Italy and Brazil, among others.

Georgilis estimated more than 30 "drift trike crews" are active around the United States, and the American Drift Trike Association has attempted to bring some organizational structure to the sport.

The association has hosted four officials races, where they attracted sponsors such as Mountain Dew, to help pay for the proper permits and other costs associated with hosting the events.

Georgilis said the association's last race, held at a ski resort in Vermont, attracted nearly 50 riders from states including Utah, Michigan, Arkansas, Texas, Maryland and Pennsylvania - not to mention a number of local television and radio news crews.

The formal events require riders to wear protective gear and follow the rules of the road, but Georgilis noted that the same standards don't necessarily apply to many of the unsponsored groups posting videos on the Internet.

"We're definitely pushing safety, because you won't be accepted as a legitimate sport if you don't," he said. "But one of the main things going on right now is the guerrillathing, where you have people just going out and filming themselves."

Despite the inherent dangers of hurtling downhill at speeds sometimes reaching more than 50 mph, Georgilis said he's heard of only a few serious injuries and no fatalities related to the sport.

Drift Trike Mafia members said they received criticism from fellow riders for not wearing helmets and other protective gear in their first video. They began wearing helmets while shooting their latest video, which was set to be released today on YouTube.

The new video depicts them on last Monday's ride down Old Priest Grade Road, along with a number of other steep or busy roads in places like San Francisco and Oakland.

Although always welcoming the threat of oncoming traffic to provide an added jolt of adrenaline, the group takes certain precautions - such as raising a hand when a car is coming up or using pilot cars-in an attempt to ensure their safety and others, said Drift Trike Mafia member Martin Sandoval, 26, a professional mixed martial arts fighter.

"We're coming down with caution. We know what we're doing and when cars are coming up," Sandoval insisted.

Valverde said the group hopes to attract sponsors who will help pay for upgraded equipment, and maybe even host a formal race, perhaps down Old Priest Grade Road, sometime in the future.

According to Valverde, they've received plenty of compliments for their antics but only the one complaint, which came from a Moccasinresident Monday. So, in the meantime, they don't plan on stopping anytime soon, he said.

"It's all about doing what you love to do," Valverde said. "Some people might say we're crazy, but it's fun."