After riding with toe clips for about ten years, I decided to give clipless a try about six weeks ago. I put my bike on a trainer and practiced for several day before hitting the road. I thought to myself, after all this practice,I'm going to be one of the few who don't take a spill. Wrong!! After a couple of tries at unclipping, I took a hard fall on asphalt when my foot would not unclip. I had to take my shoe off to stand up and had a hard time removing the shoe from the pedal! I rode the rest of the route with my left shoe clipped and my right unclipped, then fell on the other side with the same problem. It finally dawned on me that I had just screwed in the cleat partially and planned on adjusting them later when I found the proper position. Evidentially, I never did screw them in tightly and the shoe turned but the clip didn't! I think I cracked my wrist in one fall and skinned up my left knee in the other. The bad part was my riding buddies getting to laugh at me twice in the same day. After tightening up the cleats, I have had no further trouble but I sure have been nervous while clipped in. I bought Shimano Mountain Bike shoes and SPD cleats.