Bearings that are used in spinners is not actually designed for spinners but instead are widely used in skates and skateboards which are why they usually come with dust covers and are greased. Bearing lubrication plays a vital role in the life of bearings when they are under significant stress and essentially are there to separate moving parts in order to minimize friction and prevent corrosion. But because bearings in spinners are not under pressure and most likely will not be in contact with water the lubricant is unnecessary and just slows down the spinner. So what I suggest is to get rid of the grease altogether as that usually improves spin time at least a couple of times.
27
Mar