Hi All,
Am about to fit some new SKF cartridge bearings in my front hub and have been advised to pack them full of grease before I fit them.

What sort of grease should I use? Have a large tub of CV joint (Moly) grease – would that be suitable?

Cheers

Chris

Moly is really for high temperatures and high speed, although it would work ok. Maybe just a bit thick.
Try some full synthetic grease like finish line or pedros?

I assume these are sealed cartridge bearings? I would not open the seals to add more grease. I would assume the bearing manufacturer know the correct amount of the correct grease to put in and by removing seals you are likely to damage them.

They are sealed with rubber seals, not metal, and it is perfectly common to pop the seals off to clean or lubricate them!

It was the hub manufacturer that recommended I do this.

Except TJ they never use a waterproof grease because the bearings are a standard industry size not normally used in the wheel/bottom bracket/headset of a bike that spends it's life splashing through puddles.

I tend to lift the seals on all new bearings I fit, wash them clean and fill with a Marine grease. If you are careful with a sharp blade you'll lift the seal without damaging it.

Im planning on getting a pot of marine grease for just such a use. Low fling, high waterproofness. Got be appropriate stuff no?

Best place to get marine grease? (no chandlery near me)
Also while we're on the subject silicone grease any ideas? Motorbike shop said halfords, halfords said motorbike shop, fairly confident lbs will say either "eh?" or "certainly sir £20 for 20g"

+1 for wanting to know where to get hold of marine grease as I am nowhere near a chandlery

Stoner – Member

Im planning on getting a pot of marine grease for just such a use. Low fling, high waterproofness. Got be appropriate stuff no?

I'd have thought it would be relatively high friction, but am unsure that would be too noticeable in hubs and BBs.

TandemJeremy – Member
"I assume these are sealed cartridge bearings? I would not open the seals to add more grease. I would assume the bearing manufacturer know the correct amount of the correct grease to put in and by removing seals you are likely to damage them."

This is a joke right?

Plenty of marine/waterproof grease on ebay or I'm sure you can mailorder it from somewhere, get a big tub of it, I used to get Morris stuff from my local boatyard when I had a canalboat and this was used in the stern tube, so figured it ok for my bike …

Not a joke. I genuinely do not understand why anyone would do this.

A sealed bearing means no water entry so no need for waterproof grease. If water gets in the seals have failed and usually the seals fail after the bearing does – ie excess movement in the bearing destroys the seal.

Removing the seal increases the odds of the seal failing and allowing water in.

Maybe its just me but about many thousand miles on cartridge bearing hubs and only one bearing failed in that time. Winter and summer riding including once riding thru salt water over hub deep and plenty of river crossings.

Still – you guys obviously know better than SKF as to what grease your bearings need

TJ is once again spouting off like hes a white Jesus.

I'm with you TJ, from an engineering perspective lifting the seals is the single *most likely* cause of failure of the bearing. The seals are not meant to be used in cumbrian mud or immersed completely but that is why the hub should protect it from the main onslaught, and you can accept that if you go river crossing you may trash your bearings (though I've 1.5 decades from my hope cart bearing hubs and only replaced once due to a little play).

Over-packing bearings doesn't do them any good.
Using the wrong lube doesn't do them any good (though a good marine grease will be fine).
Plucking and stretching the seals doesn't do them any good.

But if you want to, go for it, just don't moan about how long they last.

Over packing bearings with grease will reduce their life
It can cause enough pressure in the bearing to cause the seal to pop & then let the crap in

Scruff. I said

I don't understand

why folk would do it – waiting to be educated / to have it explained to me.

Interesting this…. I've just bought sealed bearings for my Hope XC rear (SKF from simplybearings.co.uk). I took the seals off and was suprised to find a small amount of grease on one side and no grease on the other side. I packed them with grease and refitted the seal. Will be interesting to see how long they last then.

TJ in "taking extreme position" shocker. Oh my, it's on the basis of an "assumption" – what an admission!

The bearings put in hubs are made in high volumes for all sorts of applications – as I understand it mostly for higher-speed use indoors – that's why there ain't much grease in them.

IME most mtb cartridge bearings fail due to corrosion. Therefore: (1) seals are not waterproof. (2) Grease keeps water out. Unless you are cack-handed then (3) it's simple to remove and replace seals without damaging them. And so (4) greasing hub bearigns is gonna help.

SIMPLES!!! 😀

ps my lbw/employer got marine grease from ison. It's nice and thick but it is tough to comment on its effects.

pps What grease do folk pack shimano freehubs with?

to quote the guy in the engineering shop………….

Q: which grease would you use in XYZ?
A: this one (elbow towards grungy looking pot)
Q: which grease would you use in ABC?
A: this one (elbow towards same grungy looking pot)
Q: which grease would you use in DEF?
A: this one (yup the same one)

Al – wtf? Do you ever read anything I post? Why do you feel it needed to jump into full on attack all the time?

Sealed bearings fail – then the excess movement in the bearing destroys the seal, then water gets in causing corrosion. An equally valid explanation.

I am not the only one who would rather not risk damaging seals

TandemJeremy – Member

Sealed bearings fail – then the excess movement in the bearing destroys the seal, then water gets in causing corrosion. An equally valid explanation.

Based on what?

Based on my experience and my understanding of how seals and bearings work and based on others experiences as well.

Yours is pure conjecture and surmise so my explanation is equally valid as neither of us have anything other than surmise and conjecture

What evidence have you got that the chain of events is as you say not as I say?

You are being quite needlessly aggressive and unpleasant

I believe this thread is suffering from a lack of input from PeterPoddy at this time.

He is the true messiah of bearing care. TJ is a false prophet. 🙂

coffeeking – Member

I'm with you TJ, from an engineering perspective lifting the seals is the single *most likely* cause of failure of the bearing. The seals are not meant to be used in cumbrian mud or immersed completely but that is why the hub should protect it from the main onslaught, and you can accept that if you go river crossing you may trash your bearings (though I've 1.5 decades from my hope cart bearing hubs and only replaced once due to a little play).

Over-packing bearings doesn't do them any good.
Using the wrong lube doesn't do them any good (though a good marine grease will be fine).
Plucking and stretching the seals doesn't do them any good.

But if you want to, go for it, just don't moan about how long they last.

was suprised to find a small amount of grease on one side and no grease on the other side.

Don't be surprised, thats what happens when they're transported, grease isn't solid, it all falls to the lowest point.

TINAS – works if you're day to day engineering isn't overly sensitive. There is a reason there are loads of grease types out there, though a lot of the time it's small gains for large costs rather than application specifics.

Based on what?

Fair point. But which is more likely

1) Bearings fail because seals have failed (despite being protected from impacts/serious grit buildup etc by the hub bearing shroud, if properly designed)
2) Bearings fail because heavy use creating slightly larger gaps around the seals, meaning the seals fail, leading to corrosion and further destruction, looking like the seals failed first.

Having spoken to a few bearing manufs I've heard both said, straight from the manufacturers mouths. So both are valid answers IMO, but the act of pulling the bearing seal out and re-fitting is more likely to add a failure mode, I can't see anyone arguing that. And just because you have more grease in there doesn't mean the bearing is now grit-proof, it just means that if water gets in you get a grit/water/grease paste just as before, only you probably started with an over-packed bearing (stops the balls rotating properly and causes them to "skid").

TJ.

What makes you believe that the bearing wears first,causing play thus allowing water in past the seal?
Surely the seal not being 100% water tight, water entering and causing corrosion therefore instant wear, therefore play is just as if not more likely.

I base this on the No. of cartridge bearings I have stripped due to partial seizing, where the lube is almost absent and corrosion has started. Cleaning and re-lubing with a waterproof grease resolves the problems for many hundred of miles.

For example, I fitted a new XT HT11 BB to my mates bike for a trip to Wales. 2 day's very wet riding followed by washing the bike (no jetwash) and parking the bike up for a week caused the BB to be notchy and horrible. On stripping, the bearings were full of rusty water and very little grease. The BB was cleaned re-lubed with Marine grease and nearly 2 years on is still runing fine with no further maintainance.

And before you suggest my initial poor fitting was the cause, I can assure you I am more that qualified to fit a BB.

Read what coffeeking has posted.

I have explained myself as well as I can. is the xt bb you refer to a sealed cartridge bearing?

In most industrial applications, the grease is considered part of the sealing system and is supplied as part of the bearing kit (races, rollers and SPECIFIC amount of grease to be added during assembly come in the box.) As it is accepted that even 'sealed' bearings aren't perfect, as part of the maintenance procedure, the grease is flushed taking away the bits of carp that have passed the seals and been contained by the grease, the parts checks are checks and the bearing repacked.

As CK has said, you don't want too much grease or you get skidding, equally you don't want too little in high load applications as this can lead to micro-welding of the rolling elements to the race and pitting of the race/rollers (this is probably unlikely in most biking applications – a bigger problem will be impact loading of the roller on the race surface at low rotating speeds).

As others have stated, the average hub cartridge bearing are stock parts designed for 'average' conditions (high speed, low load, benign environmental conditions) and given the relatively low speed and wet conditions on a bike, adding more/extra grease and flushing it every now and again is PROBABLY better.

This are the musings of a bearing application engineer client of mine, whilst drinking several beers in a German hotel a couple of years ago – take or leave it, but it works for me 😉

TJ. Yes an XT Hollowtech 11, BB.

Now I'm REALLY confused…

TJ, don't you Anarchists use CountryLife butter in your hubs?

Unfortunately people rarely flush their bearings before damage has occurred, so all you have left are pre-damaged bearings getting a last sprint of life, there's no way of knowing if it was the wear that caused the seals to fail or the seals that caused the corrosion to occur. This sort of thing takes serious investigation. I too have had this conversation with a bearing manufacturer, regarding the HTII bearings in fact, and his comment was that it makes far more sense to buy cheap bearings and replace them regularly than to waste time and effort re-packing regularly enough to make a difference and carefully enough not to damage the seals, or to use fancy materials (stainless).

FWIW hub bearings are generally loaded WAY below their industrial load limits and IME last extremely well in a well designed (even basic design) hub. The HTII bearing arrangement seems almost designed to force grit and water into the bearing and trap it there, it seems like an inherently weak design and so I'm not surprised the seals can't cope. When I took mine apart there was a serious amount of junk stuck behind the tophats, being ground into the seals.

CoffeeKing, while I understand your point of

Don't be surprised, thats what happens when they're transported, grease isn't solid, it all falls to the lowest point.

this was not the case here. The bearings has a thin application on one side only when they were manufactured, it was quite obvious. As has been said, probably beacuse they are intended for domestic/industrial use and not filthy gritty biking.

Makes me wonder if genuine Hope bearings have more grease than off the shelf type?

A sealed bearing means no water entry so no need for waterproof grease.

hollow laughter – then why are mine always full of rust after 6 months ?

Because bicycles and their bearings are not designed for the life acquatic that you lead Barnes. 😀

I use Silkolene Pro RG2 available from all good motorbike dealers/shops.

They are cheap, so just change them and stop worrying.

Last time I spoke to a bearing supplier about some 68052RS bearings (same size as hughjayteens is using in his Maverick hub) their response was thus…

"What application you using them for, is it on a Mountain bike? If so, buy cheap bearings, pack em full of grease, and expect to change em often. Mountain biking subjects bearings to extreme conditions far beyond what they're normally subjected to, so pack em full of grease to prolong the ingress of water and grit, and buy em cheap cos the good quality ones won't last significantly longer!"

😕

Yeah seriously, I was a little shocked too… But then think about it, how many (similarly small) cartridge bearings are subjected to such high torque, low RPM loads, at the same time dealing with repeated jetwashing, tonnes of mud of all types, and a general lack of maintenance? Suppose he's got a point…

Let us know how you get on with the SKF's Hugh, see if they last any better… Got 2 Maverick front hubs with less than good quality bearings right now, both wheels only having done about 25 rides each.

Personally, when I buy some new bearings, I'll be popping the seal off one side, putting some extra grease in there, popping the seal back on then inserting the bearing so that the seal I popped is on the inside of the hub, leaving the non popped seal to face the dirt and grit on the outside…

I can highly reccomend Rock 'n Roll super web grease. Very good stuff, sticks like sh… to a blanket and lasts ages.

The SKF bearings I had in an Aerozine BB lasted all of about 2 months before they seized due to rust. Opened them up to find no sign of anything but dirt, flushed out and packed full of grease they lasted another year.

So empirically I'd say more grease is better.