I used Shimano SPDs to transition from toe clips. I was having a hard time unclipping. I have 4 different SPD pedals. Noticed that at about the mid way point on the tension adjustment screw, some of them have a sort of detent that takes a little more effort to adjust past. So what I'm saying is make certain that you have the adjustment screw at the lightest setting because on some of mine I think i'm at the lightest setting but actually have about 4 more clicks to go. So for me I thought I had them on the lightest setting but in fact had them at about the mid way point.