Replaced my current flat pedals with Pedal Innovations Catalyst pedal. Noticeable difference on starts and climbs, can now keep up with upright bike buddies on climbs. The Catalyst pedal is designed to support ball and heel of the foot, other pedals only support the ball of foot, even the clip-in type do not support the foot heel, which is why a very stiff shoe is needed to compensate for the non-support. To use this pedal some adjustment is needed to assure the arch of the foot is placed over the pedal spindle, I shorted the boom length to the pedal, adjusted the elliptical chain wheel one notch, and put more air in the shock (to compensate for center of gravity shift to the rear). Overall speed did not change, but climbs are much more efficient and reduced need for spin. Check out some of the articles at Pedal Innovations web site that dispute the claims that clip-in pedals are more efficient and the need to pull-up on the pedal for maximum power transfer from the legs to the bike. Also, the new foot placement feels more natural vs using only the ball of foot to transfer power. Photo attached