Kristin Armstrong will defend her Olympic individual time trial gold medal at the London Games this year.

Armstrong and world champion Taylor Phinney were among the 21 riders announced for USA Cycling's Olympic roster on Friday. The final three spots will come following the BMX Olympic trials this weekend in Chula Vista, California.

Phinney will return for his second Olympic Games after finishing seventh in the individual pursuit on the track in 2008.

"We have a strong team going to London with a solid combination of experience, leadership and young talented athletes who are all capable of standout performances," said USA Cycling V.P. of Athletics Jim Miller. "Each member of the team is deserving, we're proud to welcome them as a part of Team USA and look forward to a promising Olympic Games."

Timmy Duggan, Tyler Farrar, Chris Horner and Tejay van Garderen will join Phinney on the men's road cycling team, while the women's squad consists of Armstrong Amber Neben, Shelley Olds and Evelyn Stevens.

The track cycling team is comprised of Dotsie Bausch, Sarah Hammer, Bobby Lea, Jennie Reed, Lauren Tamayo and Jimmy Watkins.

David Herman is on the men's BMX team and Arielle Martin on the women's squad. The men's mountain bike team is made up of Samuel Schultz and Todd Wells, while Lea Davison and Georgia Gould are on the women's team.