The RC910 S-PHYRE + Ultegra PD-R8000 Shoe & Pedal Package closes the gap between foot and pedal axle from both directions at once. The S-PHYRE shoe's carbon hollow core sole trims stack height on its own, and the PD-R8000's low-profile body trims it again on the pedal side, so the two reductions stack instead of duplicating each other. That shorter path puts more of every pedal stroke into forward motion instead of flexing through extra material underfoot. What Our Gearhead(R) Experts Are Saying:"Standing up on a climb, my foot sits closer to the crank than it ever has. None of that push gets lost in flex before it reaches the pedal."