Of the many subjects that come up around here on a daily basis, a ridiculously in-depth discussion about Power Grips and the physics behind their design isn't something I ever expected.

I had a set of the original ones - with the metal clip attaching them to the front of the pedal - a couple of years ago and really liked them at first. It took me forever to get them dialed in and once I tightened them enough to feel really secure yet still easy to slip in and out of, I realized how the made my feet numb on long rides. Also, the metal clips became pretty mangled after about 3 weeks and the bolts attaching the straps to the rear of the pedals (which work the same way the "new design" of Power Grips does with the strap squeezed between the pedal and a big flat head bolt) began pulling through the strap.