Originally Posted by
tjspiel
To me the downside to PowerGrips is that they have to be adjusted right to work well at all. Depending on the tread pattern a given shoe may be difficult to get in if the Powergrip is adjusted tight enough to be effective. Riding with different pairs of shoes isn't so easy since each may require the PowerGrips to be set differently.
I also found that over long distances they caused my feet to go numb but not everyone has that problem and for short distances, even with sandals they should be fine.
If you're more concerned about foot retention than power, then adjusting them right isn't so important. If by studies your talking about the same one on the Rivendell site, that has been shot full of holes. You do definitely get more power out of foot retention, but I agree that it doesn't come automatically or 100% of the time.
Another option to consider would be BMX style pedals with pins.
Where is the study on the rivendell site? I only see a rant/article. I'm talking about a scientific study published in a sports journal. If you get more power out of foot retention then nobody told the crank arm I broke riding on the platform side of my pedals.
Pins are great for rain and slippery shoes, but they don't help when your leg cramps and tries to flop your foot off the pedal after hours of repeated hard accelerations.