Colin Ruthem knows just one speed - whatever is faster than normal.

Ruthem, 18, has been the top motocross rider in the first year of every level he has competed in Arizona .

He earned first overall title in the 125cc novice level in the E.T. Battle of Ironwood series last summer. He moved up a level to 125cc intermediate, where he placed first overall in the Ironwood series and the Big Bike Open, a racing series for all classes and levels, last month.

"I was just surprised I was able to come up and do as well as I did," said Ruthem, a Gilbert High senior. "There are more riders in the novice class, so you're used to getting into big packs and seeing other guys crashing out as you pass by them. In that class, I wasn't able to go at my real speed.

"In intermediate, there's a lesser amount of riders, so I was able to break out of the pack a little faster than what I thought."

Now, after just three years of racing motocross bikes, he is thinking about turning pro.

"His advancement has been real fast," said Don Ruthem, Colin's father. "Most guys that are at his level have been riding for a lot of years. And he's been riding motorcycles for just three years."

Ruthem will concentrate on riding in high-profile national amateur races this year to get more recognition and to figure out when he should turn pro. He will ride in a local race this month before trying a few Four-Stroke National Motocross Series races in Texas in March and April.

Other national races he will try to join this year are the CMC Copper State Classic at the Arizona Cycle Park and the prestigious Loretta Lynn Amateur Nationals at Hurricane Mills, Tenn. , for which he has to qualify through area and regional races.

Ethan Goodrich, Ruthem's coach, said Ruthem should finish in the top three at the national races and expects him to turn pro soon.

"Based on his riding and his learning curve," Goodrich said, "he probably will turn pro at the end of the season (October) or very close to the end of this season."

But turning pro doesn't mean Ruthem will be racing in the national Supercross professional events with superstars Ricky Carmichael and James "Bubba" Stevens. He must accumulate more points as a local professional to have a chance to join the Supercross series.

And that takes work.

"He has dedication to it," Don Ruthem said. "People see him out there riding and doing well but they don't see him working out on the Bowflex and on the stationary bike and eating right."

Colin said his work ethic "separates most of the guys. I put in some time and heart into it to get results. I really want to get to the professional level. I just go out there and don't have fear. I don't care about going out and holding back. I'd rather win.

"If I do crash, I know I'll just come back later and finish near the top. I push it harder and harder every time I ride. I just assume that's the only way I'm going to get better."

That attitude makes Goodrich's job easier.

"He just has a really good knack for catching on to different methods of learning," Goodrich said. "He's also a natural rider. Some people who first start riding aren't comfortable on a motorcycle. He picked that up immediately. It really lends to his learning curve. He learns a lot faster than most people."