<Dd> Angle between a tangent to the helix and a plane perpendicular to the axis . Note that the complement of the helix angle is usually given for helical gears . </Dd> <Dt> Pitch diameter, d w (\ displaystyle d_ (w)) </Dt> <Dd> Same as described earlier in this list . Note that for a worm it is still measured in a plane perpendicular to the gear axis, not a tilted plane . </Dd> <P> Subscript w denotes the worm, subscript g denotes the gear . </P>

How often does a formula 1 driver change gear