I use spray lube as well.
No grease here; we work and ride and live in the dirt. Grease plus dirt = more erosion than metal on metal. I don’t know anyone that greases the ball out here, too many gravel roads. There are two schools of thought on it and we’re the no grease faction.
ETA My husband has worked in heavy steel fabrication for 30 years-I trust his judgement on this one. If not greasing the hitch was causing any problems for the bajillions of trailers/hitches that he’s seen in his lifetime he would have changed his opinion.
We clean and grease the moving parts on our hitches a few times a year, using dielectric grease. We never grease the actual ball. It isn’t a super-close fitting metal-metal connection (except at the collar, or tab, or wedge, whatever type you have), and if it fits properly, there shouldn’t be an excessive amount of wear between the parts. Most balls are coated with alloys that include a fair bit of Cr/Ni…so they are fairly hard and resistant to that type of wear.
We’ve had a few balls experience light pitting (more evidence of corrosion than “wear”) and once that coating is interrupted, you get rust on the carbon steel underneath. Time for a new ball. Over the past ten years we’ve replaced one. But it was probably 30 years old when we started using it.
With a lifetime like that, the additional protection offered by greasing isn’t worth it to me.
If your trailer/ball sits out, or you live in a very humid (or worse, humid and salt-watery) environment, your experience could be very different. We tend to take the ball off the truck whenever the trailer isn’t in use, and store it in the truck.
