Not mentioned is the fact that the holes drilled in the axles weaken them. I know of one individual who had a wheel drop off the side of the pavement while driving and it snapped. He had the presence of mind to take closeups of the broken stub. There was evidence of cracking at the grease hole location indicating that it had started to fail before the catastrophic event. Any time you drill a hole in a forged part you interrupt the grain structure of the steel and create a stress riser. Also seldom mentioned, too much grease can lead to over heating.