Well I started out with SPD clipless and had the problems with numbness after 25 to 30 miles, even changed from swb recumbent high crank to Tour Easy long wheel base lower crank. Still had problems with numbness. Bought speedplay Frogs, had to shave my shoes to make them work, Now I have no problem with Numbness. I believe the ability to move the feet at more of an angle solved the problem. Larry