Originally Posted by
Scrodzilla
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.
There's also another difference with the fixie design. The straps are attached in two locations, presumably to prevent the rotational wear on the strap hole that occurs with the standard design (pictured here):
And once again this improvement could also be implemented by using the cage mounting hardware that's already included with every Power Grip compatible pedal.
Was this on a fixie? If not then you shouldn't really be pulling on the pedals anyway. On freewheel bikes the purpose of foot retention is to keep your feet from slipping off the pedals while spinning and while tossing your weight around. That's why I want to try Power Grips because on the upstroke you really just want to keep your foot from contacting the pedal, which should be easier with a looser retention mechanism. That and the fact that I make heavy use of variable foot positioning on my SS bike and SPDs compromise this technique.
I have to admit I wasn't aware of the Power Grip durability issue, but that also makes me wonder why the hell are people buying them because it should be easy enough to use a more durable strap material.
Originally Posted by
LesterOfPuppets
The hole in the strap is a weak point. Having it jammed into a hole with a tiny cone shaped bolt puts way more stress on the hole. Having the hole and much more strap material squeezed between two flat surfaces (like between PowerGrip bolts and the pedal face) is going to offer great advantages when it comes to hole integrity. In many such applications designers will use bolts (Often tacks in leatherworking and upholstery trades) that have a concave back side. This puts the pressure from the fastener away from the hole which can help in many applications.
Exactly, the countersinking moves the pressure away from the strap hole just like a concave washer, but better because it also makes it more difficult for forces to tug at the hole due to the 3D labyrinth and the jamming effect. Countersinking is to washer what bolt/screw is to peg.
Besides, there's no reason why one couldn't replace the cage mounting hardware with longer bolts, larger flat or concave washers, or whatever you need to make it work better and it'd still be cheaper and lighter than a bona fide Power Grip kit.