You won't find many 75-year-olds in El Tour de Tucson. Or the Old Pueblo Grand Prix, for that matter.

At the Tucson Bicycle Classic, all are welcome.

And these 75-year-olds can haul.

"They're not like outdoor Sunday riders. Some of them are extremely competitive and strong," said TBC founder Steve Bohn. "They put a lot of riders half their age to shame, and they kind of do it on a regular basis."

The 27th Tucson Bicycle Classic starts at noon today and lasts through Sunday. Here's all you need to know about the second-longest running race in Arizona:

• What is it? The TBC is a three-day, sanctioned stage race.

"Like a little mini Tour de France," Bohn said.

There are 20 different categories based on age and skill, ranging from boys and girls ages 10-12 to men and women 75 and older. In total, there will be about 540 participants; Bohn said 10 percent to 15 percent won't finish the race.

In terms of distance, the mileage varies for each age group. For the junior groups (10-12, 13-14, 15-16) it ranges from 12 miles to 40 miles. That number rises with age and skill level, capping at 80 miles.

And, like the Tour de France, everyone who leads their category gets to wear a yellow jersey.

"If you want to compare it to the El Tour de Tucson," Bohn said. "The difference is this is a sanctioned event."

Meaning, it is run by USA Cycling, an organization that sanctions races all over the country.

There is a $7,800 cash purse, and some of the age-group winners receive awards. The professional men and women have a combined cash purse of about $3,500 - the pro men's field has close to 75 people, while the women have about 25.

• Where will it be? The Classic consists of three races - a time trial, road race and circuit race - over three days at Southern Arizona sites. Today's time trial will take place at the 3.2 mile Old Tucson/McCain Loop near the theme park. Saturday's Garrett Lemire Memorial Road Race will be held in Sahuarita and Sunday's PCC West Circuit Race happens on the west side.

• Who'll be there? Some of the best racers in Tucson and from surrounding states come to the Old Pueblo for the race.

Gord Fraser, for one.

Fraser, who lives in Tucson, has more than 200 career wins, is a three-time Olympian for Canada and raced in the Tour de France. The 44-year-old Fraser has won the TBC multiple times.

"He was in a breakaway at the (Old Pueblo) Grand Prix last week, stayed ahead almost the whole race," Bohn said. "Some of those guys are half his age."

The women's winner of that race, Leah Kirchmann, will be participating this weekend as well. In addition, Bohn says there will be four or five domestic professional racing teams.

No matter the age or skill level, everyone who leads their group gets a yellow jersey.

"Everybody from 10 to 12, to professionals, to masters 50 to 70 or whatever, everyone gets one," Bohn said. "Each race leader gets to wear one. That's what's cool: It's not just for the pros."

If you go

• What: Tucson Bicycle Classic

• When: Today-Sunday at three Southern Arizona sites

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