Radicon Double Helical Single Stage High Speed Gearbox The TAD turbo Gear unit is a single stage step-up or reduction gearbox with horizontally offset. It is designed as a single helical gearunit.to the thrust collar technique. The tooth thrust resulting from helical teeth is being compensated through thrust collar. Spec Detail Prime Mover Power 4411 kw Input Speed 8333 rpm Ratio 2.077 :1 Service factor (Min) 1.7 as per AGMA Type & Size TA 35x