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I usually pop off the seals on pivot bearings and top up with the above type of grease...
But am I right in thinking that for fast spinning bearings a thinner grease is better? Also don't fill them with so much grease?
Cheers!
Fast is relative, machine bearings at X thousand rpm at completely different to bike bearings which normally fail due to corrosion from water ingress.
Pack away, the bearings last longer.
Standard bearing industry testing for ball bearings do not relate to bicycle applications. Most bearing industry testing for the smaller radial bearings used in bicycles are performed at very high RPM (over 5,000-10,000 RPM), and with only light loads applied in a radial direction. Bicycle hub bearings spin at 200-300 RPM and bottom bracket bearings rarely exceed 120 RPM in most situations, and both with much higher radial and axial loads.
Obviously if you are full racer bro you should degrease the bearings and lightly oil them for weight saving and maximum gains!
Cheers for that! Will pack them out then.
Definitely no weight weenie! Lol
Youre probably more likely to damage the bearing by popping the seals and over packing IMO. Never had a wheel bearing go that wasn't already compromised in some way.
Also, ultra thick grease? Use the proper grade and maintain it properly.
I am of the view that bearings fail when the seals fail and let in water - so removing the seals makes seal failure more likely
If you must do it remove the bearings and take off the seal that is most central so the outer undamaged seal is the one that is needed to prevent water ingress
This. Grease absorbs water so won't prevent oxidation in the long run. Better to keep the water out in the first place.
Grease absorbs water so won’t prevent oxidation in the long run.
That's like saying grease is pointless.
It's easy to remove a seal without damage.
Any failed bearing I've seen had **** all grease in it.
Don't remove the seals - chance of invisible damage is too high IMO - just buy ones that come fully packed from the factory.
https://www.endurobearings.com/products/bearings/max/
May or may not be available in wheel sizes though, I didn't check.
Ah, just saw that the same company also has angular contact bearings for wheels, and they are designed to be greasable so assuming they come apart. Not sure how you'd tension them in a standard setup though.
If only Kaesae was still with us. 😞😔
It’s easy to remove a seal without damage.
It's also easy to completely cock it up and make a ham fisted mess of it. Take a guess as to which side of the probability fence the person who has to ask sits on.
Any failed bearing I’ve seen had **** all grease in it.
And how do you think that might have happened?
They will drag an unbelievable amount if you fill them with grease. About 1/3 full is right.
It’s also easy to completely cock it up and make a ham fisted mess of it
Erm...both are easy? Make your mind up!
And how do you think that might have happened?
Cos there is **** all grease in them to start with, as per bigyan's post, not needed in their intended applications.
They will drag an unbelievable amount
LOL, yes they really slow us down.
ive taken appart the max fill bearings and they have had a minimal amount of standard grease in them
if replacing pop seals with a blade (seal picks i find too thick) and pack with xhp222 or lithium
ive taken appart the max fill bearings and they have had a minimal amount of standard grease in them
Not sure if you are aware, but "max" bearings actually refers to extra ball bearings inside, rather than the grease fill and is aimed specifically at high-load applications like frame bearings, rather than wheel bearings. Like others here, I prefer to open up new frame bearings and pack them absolutely full of marine grease (Mobil 222 or similar). Makes for a bloody awful wheel bearing, but works great on frame bearings!
Marine grease is pretty good at resisting water - it has to fight off salt water for a start which is serious stuff, a lot more so than that in the puddles you might go through.
I used to use Castrol CL (marine) grease in my XT hubs and it was significantly better at not breaking down than all the 'in-fashion' bike greases of the time, including lithium.
Sealed bearings are not the right type of bearing for mtb pivots as they are not spinning fast, just taking loads of stress with little rotation - so I don't think packing them with overly thick grease is going to be a consideration, it might be better. Drag is not an issue, when they are under pressure they will move sufficiently, and they don't move much anyway.
Overpacking bearings is an issue at work with high speed rotating equipment, heat generation and grease subsequently breaking down, Not an issue with bikes IMO.
Yes, you can damage a bearing by popping the seal off, if yer a ham fisted galoot.
I'd never fit a bearing without popping the seal off for a look, YMMV.
The type of seal on 'RS' bearings was developed with the primary objective of keeping grease in rather than water out. I always pop the seals off new bearings with a scalpel blade and pack out the grease - I don't think the risk to the seal outweighs the benefits of the grease and as commented above these bearings are designed for high speed applications and don't have the amount of grease from new that benefits a cycle application.
yes i am aware of max fill being the bearings but some suppliers also use it (in cycle applications) for grease fill (i purchased them especially with this option)
Grease absorbs water
Are you sure that oil based grease absorbs water?
My worry with packing out new bearings is that
1) The grease may not be compatible and therefore you may get breakdown of grease.
2) I can't really be arsed.
The grease in most hub and pivot bearings is paltry. Horrible, thin, transparent, snotty stuff that's not going to work well at keeping dirt and water out once the seals eventually fail.
Low rotational speeds and the operating environment of mountain bike sis very similar to plant and construction equipment. For high loads and good resistance to washing out due to water ingress, the stuff to use is Lithium Complex (Red) EP2 Grease. Sticks like s**t to a blanket - if you get it on your clothes it won't fully wash out.
Next best stuff is Lithium EP2.
extra ball bearings inside, rather than the grease fill and is aimed specifically at high-load applications like frame bearings,
Yes, and isn't it a thing that the groove ground into the race to get them in actually causes wear?