From a counselors perspective this is not at all about getting dropped - it is about an insecure woman with friendship issues. She is afraid of being abandoned as a friend and the ride is just a metaphor. Blatant honesty with her about you being afraid that you will become another one of her "people I put on my vendetta list" simply because you have differing goals is the only and best way to solve the problem. Put the challenge on her to find a way to find a way to accept the fact that you can still like her AND go on bike rides without her.