Lock N Load - Nitro Circus 4

Travis Pastrana
Title: Pro action sports athlete
Pastrana is the Ring-Leader of the Nitro Circus Crew, and is usually the first to attempt any stunt involving dirt bikes or BMX bikes.

Andy Bell
Title: Washed-up motorcycle rider
Former FMX rider. Bell holds a rivalry with Pastrana involving Big Wheel tricycles stemming from the first episode of the series.

Jolene Van Vugt
Title:Pro moto cross racer
Canadian Female Motocross Champion. She joins Pastrana in many stunts involving dirt bikes. Van Vugt took on more of a cheerleading role in the second season after breaking her arm and can be seen wearing a pink cast throughout the season.

Jim DeChamp
Title: Pro mountainbiker
Pro mountain bike downhill racer and freestyle rider. He has been friends with Pastrana since childhood. They collaborate on many stunts together on the show. Became the first person to land a front-flip on a motorbike to dirt, as seen in the last episode of the first season.

Erik Roner
Title: Pro skier/base jumper
Pro extreme skier and base jumper. Roner is usually the first to attempt any stunt involving snow.

Tommy Passemante
Title: Construction worker
A former Stunt Rider (Street-Bikes). Known by his nickname "Street Bike Tommy", which he received after a failed stunt where he attempted to front flip his GSXR into the foam pit, Overshooting and breaking both his legs. He is the general comic relief member of the crew. Usually used on stunts that are the most dangerous while requiring the least amount of talent.
Greg Powell

Title: Travis' cousin
Pastrana's Cousin. Powell goes by the nickname "Special Greg". Special is the all around member of the team, and generally attempts any stunt on the show. Greg was a wide receiver (primarily used on special teams) on the University of Maryland football team from 2003–06.[2]

Besides the Nitro Crew, a number of other athletes and members of the production crew made regular on-screen appearances, including executive producers and creators Jeremy Rawle, Gregg Godfrey, Jeff Tremaine and Johnny Knoxville, mechanic Hubert Rowland, former motocross rider Ronnie Renner, pro wakeboarder Parks Bonifay, and pro skydiver Scott Palmer.