To lube them or to stop water and dirt ingress? or both?
Can you put too much in?
Loose bearings?? Sealed?? Bearing races??
Don't pick the seals out of sealed bearings
Grease is to lube, seals are to keep the water out
In sealed bearings TJ, just an idle question to be honest. Looking at my cheap headset that is gritty so have cleaned the grease and muck out and put fresh grease in to prolong the life until i find out what the bearings are!!
Its an FSA 1.5" to 1 1/8 step down (think its an orbit but not a z as they are £50 and its OEM on the Cannondale Prophet)
TJ, re seals, fair enough when they are new but if your bearings are rough and you are skint there is little choice.
OK - Stuart - I have done that too and got a couple more weeks out of them
As is the singletrack way, someone comes along and posts the opposite view. I personally believe that the limited amount of grease in sealed bearings is because of the high speeds and temperatures that may be required of them.
On a bike, they're never going to go anywhere near as fast or as hot. Yes, you can damage the seals by lifting them but they're flexible rubber so you can get them out without damage.
I find that cleaning out the old stuff and packing them with a thick waterproof grease like Silkolene RG2 does make them last longer. It could be that if they're full of grease, there's no room for mud, water and grit.
It's not a hugely scientific test but I once did one side of a hub like this but not the other. The modified side lasted longer. I'm happy to change my opinion if someone has more indepth analysis than that though.
My old Enduro bearings lasted for years by removing the seal,bit of grease & then replacing the seal.As long as you don't go at the seal like you wanna kill it they'll come out easy enough with no harm done....