When you increase diameter and decrease weight of a shaft, you increase its Critical Speed. The Critical Speed of a rotating shaft is the speed in which it begins to see extreme resonant vibrations and becomes unstable. In terms of a sprint car drive shaft, this is when the drive shaft starts to turn into a vibrating jump rope, which typically leads to pre mature U joint failure. Titanium is extremely forgiving, as its fatigue resistance and high tensile strength makes for the perfect material for a properly designed drive shaft. Our drive shafts have the perfect balance of weight, strength and forgiveness of any drive shaft available, PERIOD.