I poped the seals off my external BB and after 3 mths summer use the non drive had no grease and was rusting to the point of seizure.
I would prefer not to pop seals but see little to be gained in not doing this as MTB is noit their ideal scenario.
Marine grease – if you live near a canal-there will be a chandlery shop/diesel point about every 10 miles ish to get grease. It is not dear but you will need to get bigish tubs.
I am not entirely sure if it is inherently any better than normal grease but it is designed to lubruicate the propshaft and stop the ingress of water through the thingy [cant recall name at minute but the hole in your boat where prop enters engine bay]. I would have thought all grease was waterproof not sure why it would be better.

FWIW in 10 years of mtbing, I have to agree with Cynical-al and that Bowden fella.

IME grease gets washed out first, and then corrosion sets in. I too have rejuvenated part-seized bearings that are relatively young, and after being packed have lasted a reasonable service life.

That said, cheap bearings replaced often seems to be the least hassle overall.

Anyone that thinks sealed bearings are truly sealed should take a close look at them. On many, especially the cheaper bearings, the rubber shroud doesn't actually touch the inner race, but is a close-tolerance fit – i.e. there is actually a gap there.

If anyone thinks bearing play (movement between inner and outer races) causes seal failure, I'd urge those people to go and seriously examine how much play the rubber seal has – Its quite substantial, and is why, if you're careful, its easy to disturb the seal to re-grease the bearings. Acros and a number of other component manufacturers actually recommend you can do this as part of what is regarded as normal servicing.

junkyard- nothing to contribute to bearings, but the boat thing is a stuffing box. My favourite boaty term. 🙂

What an entertaining thread 🙂

Phil Wood waterproof grease.

hollow laughter – then why are mine always full of rust after 6 months ?
BigDummy: Because bicycles and their bearings are not designed for the life acquatic that you lead Barnes.

so "sealed" means "only splashproof" ??

I had "sealed bearings" in a bottom bracket once. They were only sealed on the outside so any water inside the frame had no problem getting in.

This article suggests Castrol CL but I find it a bit thin
http://www.offroadadventures-online.com/tips3.html

This seems thicker but I haven't had it in long enough to find out if it lasts well.
X-tra Heavy Duty Bearing Grease Marine Spec
http://www.dukeriesengineering.com/10325/info.php?p=11&pno=0

TandemJeremy – Member
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

Conjecture? Like your arguments? My many years LBS wrenching counts for nothing?

To follow your justification, I could quote Maverickboy, bristolbiker, Michael Bowden (how did he get a space in his name?) etc etc.

My (wrench) experience is that failed bearings have **** all grease in them, and (personal) those with lotsa grease last longer. No way is the "seal" actually waterproof, esp when a piece of grit etc gets in there. Have you ever taken a seal out? Seriously, there need be no deformation ,even if a tine bit was relevant.

I guess my point is that you persistently argue (& frequently take extreme positions on) points that you admit you don't know much about – you even admit to assumption in your first post. You should direct your efforts towards a field where you can truly prove yourself (go on mastermind?) rather than the internet.

I'm not the only one berating you for this behaviour for the last few years am I?

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.

*puts hand up*

al – why do you feel the need to attack me all the time? My points were logical and not without support from others. Your own arguments are full of holes that I could easily pick apart

And why beholdest thou the mote that is in thy brother's eye, but considerest not the beam that is in thine own eye

I will not engage with you at all anymore. I find your charging into the attack without reading what I say extremely aggressive and unpleasant and you have shrunk in my estimation as a result

Hey guys. I have cheap off the shelf bearings, INA SKF and Enduro max in stock. What say I take 3 of each bearing water proof one with moly thin greaser one with thicker standard grease and one with nothing throw them all into some containers with water and we will see what happens to them. The fact that they are constantly submerged in water should speed up any process that occurs and let us know a bit more about the situation. If you want to do this let me know and we will see what we see.

:lol:Nice one MaveickBoy…"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"….

Having worked with bearings for more than 30 years in industry, I can vouch for the grease packing theory. Many of the high speed conveying systems I work on, have bearing housings with grease nipples for periodic re-greasing. These are running 24/7, 50 weeks a year, with many running for 10+ years. One thing I have noticed on these bearings, even after wiping away excess grease from them, is a fine line of grease running around the lip of the bearing seal, lubing the seal and filling any tiny gap in a cappiliary (did I spell that right :|) way.

On the subject of grease. Not all grease runs or flows as mentioned elswhere in this thread. Some greases are almost like lard in their consistency, and only work well when warmed, then the grease starts to flow. This isn't a problem for the likes of cars, motorbikes etc. where the speeds and brake heat help to warm the hub bearings when in use. Whereas on mtb the grease hardly ever warms. This can lead to a situation where the balls and race in mtb bearing are virtualy bare of any surface grease. Muddy water getting past the tiny lip seal will very quickly corode these parts when the bike is parked-up. The resulting pitted race and balls, along with the rust particles and remaining gritty water, will accelerate the wear very quickly.

While i'm on a roll….BB bearings (as has been mentioned a few times on here) nearly always seem to fail on the none drive side first. My theory on this is, the drive side crankset offer protection from thrown-up crap and spray, whereas the contour at the back side of the non driveside crank offers a nice little V shape to guide any unwanted crap into the seal area of the BB.

And finaly, Chris King obviously believe forcing more grease into a BB will increase its life. As I do with my take on BB re-greasing 😆

poor grammar aside, 5spot has it!

TandemJeremy – Member
al – why do you feel the need to attack me all the time? My points were logical and not without support from others.

as were mine. Cos you have an internet-research/assumption-based opinion on pretty much EVERYTHING.

Your own arguments are full of holes that I could easily pick apart

Bring it!…oh but at this point you say:

I will not engage with you at all anymore.

How convenient!

And why beholdest thou the mote that is in thy brother's eye, but considerest not the beam that is in thine own eye

I have no idea who you are quoting but it seems to me like you are trying to sound cleverer/more knowledgeable than me. Have you applied this "reasoning" to yourself?

Let's have a pint some time. I still have your tools and you owe me some chain lube.

Al – I will e mail you.

Sad I know but I've popped both seals off one bearing, cleaned it out, filled it with Silkolene RG2 and fitted it on the disc side of a hub with a non treated bearing on the other.

Not the worlds most scientific test but I now always pop the seals and give them a proper filling. After all, my hubs spin a lot slower than the design speed so a bit of extra grease isn't really an issue.

The viscosity of the grease in relation to its resistance to environmental factors will determine the best grease for this application.

What Simon said 'Phil Woods' bearing and it's nice green colour.

very nice fivespot – I remember you posting up the thread when you did that. I assume its still running well?

Also, where did you get the grease nipple from?

kaesae – by what action does bearing grease viscosity relate to environmental factors and how does it improve the situation? I presume you're suggesting a thicker grease = better, though I can't quite determine that from your post?

Scienceofficer….its still the same one, and still going strong. The grease nipples are from industrial spherical joints. They are almost identical to the Zerk grease ports found on Turners, and use the same type of grease gun.

fivespot – do your bearings have a seal on both sides ?

won't you just pop one or other off eventually ?

scaredypants-the bearings are original HT II items, which have a conventional rubber lipped seal on the inside and a unique Shimano design seal on the outside, which has a lip that works against the inner face of the plastic tophat/sleeve. I use a light semi fluid grease (usualy one shot after a wet/crappy ride) which, under pressure will displace some of the existing grease past the seals. No popped seals.

I've worked in engineering for 28 years currenty work at a papermill. Over 1000 bearings on one machine. We only use SKF and FAG in most positions and I'm in regular contact with the service guys at both.
SKF technical support at Luton if anyone wants to contact them.
SKF recommend a bearing is filled to about a 1/3 with grease in sealed-for-life bearings but these bearings will be running at up 3000rpm not 100rpm like on our bikes. Also they wont be subjected to the crap our bikes are subjected to when riding through the rivers and puddles as I have been today!
SKF have advised me in the past on a particular job in work to remove the seals and re-pack with a different grease. So I dont see a problem with removing seals (carefully).
I've always removed the seals and re-packed them full with waterproof synthetic grease in my pivot and BB bearings with no problem. Overpacking with grease is not recommended when they're doing 3000rpm. Not a problem at 100rpm. In fact at 100rpm they're probably generating enough speed to set up a hydrodynamic lubricating film which most of the greases are designed for. The only reason I overpack is to keep the water out!
Just my opinion. I'm sure someone will disagree.

Coffeeking. There are two main factors for consideration as I see it in this situation and relative to the evaluation of what is required through analysis to determine which grease is best suited to this application. Do you agree that there are two main characteristics required from the grease ?. Longevity and rotation of the bearing.