whether it be in overall balance, critical clearances or improved design, our flywheels are built for performance. Machined from the highest quality 6061 T6 or 2024 T3 aluminum, each flywheel is manufactured to deliver optimum tensile strength, heat dissipation and weight reduction, without going too light and causing poor idle and driving issues like some of the ultra-lightweight competitors. We aren't always the lightest, but we are the best! Flywheel-Aluminum PC Nis18HR; High Performance, Lightweight with Replaceable Friction Plate