Would like to add some grease to my sealed bearings as I rode through a stream. Cant see any water with the eye, so don't think they're in any bad shape, but thought it would be a good idea to just add some grease. No idea what grease is in there from stock. Does it usually matter?
Can you mix greases
- Thread starter Ricker
- Start date
ctguru
Likes Bikes and Dirt
Yes, some greases aren't compatible with each other
I think you will find that the greases that aren't compatible are synthetic and organic. i.e. don't mix a synthetic with an organic. Reason for this is the same as synthetic and organic engine oil, they actually break down the lubricant within one another
EDIT:
After more investigation:
It's all about the base or thickener that is used in the grease. Some bases and/ or thickeners are not compatible with others, conversely some are compatible with others.
If two greases that are incompatible are mixed, one of two things can happen, it can harden, or it can soften and release all of the oil. Basically same scenario, you lose lubrication.
Bottom line: without knowing your grease, purge, clean and re-apply
EDIT:
After more investigation:
It's all about the base or thickener that is used in the grease. Some bases and/ or thickeners are not compatible with others, conversely some are compatible with others.
If two greases that are incompatible are mixed, one of two things can happen, it can harden, or it can soften and release all of the oil. Basically same scenario, you lose lubrication.
Bottom line: without knowing your grease, purge, clean and re-apply
Last edited:
teK--
Eats Squid
what he said. Its all about the base. if in doubt start afresh.
Can someone offer me up a hardcore degreaser for this very task of purging the old grease out. I have some generic diluted degreaser for my chain etc, but I don't think its up to the task of breaking down pure thick grease in bearings.
On another related note:
My bike is a new 2014 giant trance 27.5. It has sealed bearings in the giant hubs. I took off 1 dustcover which exposes the bearing I think, but I don't reckon I can actually take the bearing out. Never done this before, so from this photo what are my steps for getting access to the bearings. Is it simply just removing the rubber looking seal? How do I access the other side of the hub? bash the centre pole through to pop off the other sides dust cover? I mean i'd unscrew it but the only way to undo the dust cover is to torque against the opposite dust cover, and only 1 comes free…
(I got recommended to replace grease, because I rode through streams.)
Heres pics.
hathill
Likes Dirt
That looks absolutely fine - my advice is don't touch it unless it feels crappy/noisy etc.
The excess grease on the outside there is perfectly normal.
silentbutdeadly
has some good things to say
I agree. Leave them alone.
But for future reference, you can bop them out with a soft head dead blow mallet by tapping firmly on either end of the axle. Getting them back in should be done with a press (which can be simply a large bolt with nut and a socket).
They aren't worth degreasing/re-greasing since sealed bearings aren't designed for such treatment and new ones are not expensive - the last pair I bought for some Novatec hubs were better than OEM and $24 from a bearing shop in town.