Originally Posted by
3alarmer
...you probably know this, but I'll mention it anyway. All the Shimano aero pedals in that style are roughly equivalent, except for the Dura Ace logo.
No, they're not. The PD-6400 version of the pedal used standard ball bearings and axle with an "aero"-style body and the proprietary 3-bolt toeclip, so it superficially resembles the Dura-Ace pedal. The PD-7400 Dura-Ace version used roller bearings and two different ball bearing races to accommodate a lower profile body for greater cornering clearance.