I have read that just placing nipples on the top of the kingpins is next to useless as the oilway down through the kingpin is so small that grease cannot get through in sufficient quantity to do any good.
Ideally this oilway should be drilled out. Or replace with new kingpins that are now already drilled with a larger bore for this reason.
I think I'll continue to grease as normal...with the occasional prod of the oiler for good measure.
