I'm a flyweight guy (105 lbs.) and it's difficult for me to break anything on any of my bikes. Never broken a spoke, even on my MTBs (I generally ride cross country, might have more luck breaking things if I was seriously into downhill). Bunny hopped a curb once on my MTB, not knowing my rear tire was flat, and barely even dented the rim. As the others have said, the frame and components of that bike aren't ideal for mountain biking, but at her weight it should handle mild trail riding and minor technical stuff like bunny hops over obstacles just fine. Definitely get her something better if she starts serious riding.
Last edited by rnorris; 05-06-09 at 02:09 PM.