GrahamHR
Well-known member
I suspect the answer is to do with trying to improve efficiency at moderate speeds.
The cones are easy enough to remove and replace ... think of them as a nicely shaped prop nut that is harder to drop
You don't need any special tools to remove a cone, just a large socket and a smaller one for the additional lock screw on DP-D and later.
The cones on the DPH drive are held in place by the nut securing the rear prop, 30 mm and a flat faced nut rather than a teper one if I remember correctly.
The forward prop is held in place with a flat faced nut, fitted using using the same tool as DPS use.
DPS drives use nuts with a taper( modern practice in all modern automotive applications, including bearings). The DPH type seem archaic, for no reason. Again, it seems like a "not invented here" syndrome effect.