An added note to this thread is that I really appreciate the information about stress to the achilles, especially since I ruptured my right achilles tendon about four years ago. Nine weeks in a full leg cast almost put me in a funny farm. I had noticed some tenderness in my ankle after some strenuous rides but wasn't putting the info about gears and stress together. All the more reason to learn what will work for me and learn the right way so as not to cause further injury. Thank You!