I had the same problem until I went clipless. I never solved it and maintaing weight on the pedals all the time for 6+miles was not easy for me. Since I went clipless my legs have taken so much less of a beating. I am however going faster, so I can say this from experience, don't worry about unclippping in a crash, you will be flying over the handlebars never having remembered unclipping. I proved that twice tonight.