HT stands for High Torque… Seriously High Torque! This EVIL design is built to withstand high torque Harley/Custom engines and packaged with an ultra performance clutch to match. Our unique clutch design allows for increased capacity with less spring pressure and better heat dissipation. The HT Belt Drive is a HOT (Helical Offset Tooth) design that will reduce belt drive associated noise up to 30% over standard belt styles. Vibration is also significantly reduced in the HT Belt Drive. How do we do it – the continuous rolling engagement belt design always has 3 teeth fully engaged. Standard belt drives only have one. This feature increases horsepower capacity significantly and eliminates energy loss found in typical belt drive designs due to slip and stretch. The HT Belt Drive is completely self-centering, which means reduced drive face width and reduced weight. Bottom Line – Stronger, Quieter, Lighter, Better. Now that’s Mammoth quality!