Lack of trust. Or, really, too much need for trust due to a lack of self-trust. She is afraid of you dropping her off the bicycle because she doesn't know how to catch herself but she thinks she is afraid of you dropping her off the bicycle because you are a lame bicyclist. In another situation she might be the LD partner because her inability to catch herself would lead to her rejecting sex with an Evil Kneivel husband because she would think "He just wants sex for his own ego gratification. He doesn't care if I fall off the back of the bike.".
"Tell me, what is it you plan to do with your one wild and precious life?" - Mary Oliver
