15-times AMA champion Ricky Carmichael will switch from two to four-wheels next season after signing to start a new career with MB2 Motorsports in NASCAR.

Carmichael, considered one of the greatest motocross racers of all time, will join the Bobby Ginn-owned MB2 operation on a development programme, which will see him competing in the junior ranks of NASCAR's tier system in 2007.

The Floridian - holder of a record 144 career wins in AMA Supercross and Motocross - only retired from full time motocycle racing at the end of the 2006 season and will now start a new multi-year MB2 NASCAR contract, which general manager Jay Frye revealed would begin with a combination of approximately 15 events in late model stock cars, ARCA and possibly the Craftsman Truck Series, before picking up pace in 2008.

"There were other teams showing interest in Ricky, so we are thrilled that he decided to join MB2," said Ginn, who purchased majority interest in the team in July, "He brings many intangible qualities which have made him one of the great champions in all of motorsports.

"What's even more remarkable is that he has achieved a legendary record and is still in the prime of his racing career. He has both the physical and mental skills to make a successful transition from two wheels to four wheels."

Carmichael is still planning to run an abbreviated Supercross and Motocross schedule next year, staying with Team Makita Suzuki, but the 26-year old is thrilled by the prospect of making the switch to four wheels.

"I am excited about joining MB2," he said, "After talking to Bobby, it was evident to me that this is an organisation with a strong commitment to competing at an elite level. It's a good fit and I can't wait to get started. However, I plan to always ride some events in Supercross and Motocross - the sport has been very good to me over the years.

"To race in NASCAR has always been a dream of mine," he admitted. "This is a new challenge and I have no illusions that the transition will be easy. I truly understand the difficulties that are ahead, but I am committed to doing whatever it takes to eventually make it to the (premier Nextel) Cup series."