Originally Posted by
PoorInRichfield
With SPDs, I've noticed that shoes make a huge difference as well. Some of my shoes only contacted the pedal on the metal contact surfaces for an almost sloppy connection, while others contacted the pedal in multiple areas with the rubber treads which made for a more stable platform but harder release.
I think this might be it. When I used road-type shoes with SPD, they always released easily. With mountain-type shoes, they sometimes snag on the rubber cleats.