Call it the Old Pueblo Grand Prix, After Dark.

This year's version of the cycling race downtown won't start until about 6 tonight, fostering a party atmosphere in conjunction with Second Saturdays downtown.

The women's professional race starts at 6 p.m. and lasts about 50 minutes. After an hour or so break, in part so ticket-holders at the Arizona Theatre Company can drive to their show at the Temple of Music and Art, the men's race starts at 8 and runs until around 9:15.

The third annual race is free to the public.

"The marquee event ends up being an entertainment spectacle," race promoter Kurt Rosenquist said. "It's an overall entertainment package at night."

Volunteers will be distributing flyers downtown, trying to lure Second Saturday participants into catching the criterium race that runs a six-tenths-of-a-mile loop through downtown.

A two-story HD video screen will project video coverage of the race near the start/finish in front of St. Augustine Cathedral.

"That works better at night," Rosenquist said.

Here's a look at other changes this year:

• Fewer amateurs. Last year, Rosenquist ran amateur races throughout the day before turning to pros. This year, a different group is organizing the amateurs, who can ride the course during the day. The rectangular course - South Stone Avenue north to West Jackson Street, east to South Scott Avenue, south to East 14th Street and back to Stone - will be closed to car traffic during the day.

"For the public," Rosenquist said, "it's more to attract spectators and watch the pros compete."

• More money. The purse has increased from $20,000 to $23,000, in part because of USA Cycling rules requiring equal pay for male and female competitors.

• Better racers. Rosenquist expects about 120 pro men and around 100 pro women this year, in part because the race is the first on the schedule for two governing bodies, the National Criterium Calendar and the USA Criterium Championship.

Some cyclists have spent weeks in Tucson training for the start of the season.

"We are the opening race," Rosenquist said. "Everyone has to be here."

• There's an expo, and a party. A kids' race and bike parade starts at 5 p.m.

A BMX exhibition will take place during the hourlong break around 7 p.m. Adults can participate in a 200-yard beach cruiser race then, too, with the prizes sponsored by a beer company.

"The whole thing," Rosenquist said, "will be a lot of fun."

If you go

• What: The Old Pueblo Grand Prix

• Where: Downtown Tucson (see map)

• When: Parade and kids ride at 5 p.m; first race at 6 p.m.

• Detailed information: