The Piper G14 Disc 125mm Inline Skate Wheels are made with the original G Thane formula and a supercharged banded core (67A) that really gives them an extra oomph. The disc core is 89mm in diameter but very lightweight so it can quickly disperse the energy from the center into the outer tires.
 
They're great for marathon skating or any long-distance skating where one would like a wheel that is fast. The profile has a small footprint which even further promotes speed by barely touching the ground. They are made in the U.S. and they are sold as single wheels so that you can replace them as needed.