The door mirrors that were on the truck when I bought it were cheap aftermarkets, that had been re-drilled to move the heads on the arms. But they drifted even below legal speeds, and required constant re-aiming.
So I bought
some new ones, knowing that they'd have similar problems, but hoping for an improvement. It was very slight - they'd hold at low speed, but drift at highway speeds.
Later, I swapped again:
