[Closed] Topping up bearings with grease

You will get different opinions on this. Personally I think pulling the seals damages them leading to water getting in and early failures

I lift mine - nice sharp blade and carefully - and put extra grease in
I also don't buy the other argument about the grease being less efficient, even on a wheel bearing the rotation is slow but for BBs and especially headsets, it's a definite for me

I'm with scardeypants on this one.

I'm with scaredypants too. Prise open, pump until full then rotate left and right.

You'll only damage the seal if you're a ham fisted chimp. While the seal is metal backed, the actual lip is flexible.

Bike bearings don't run anywhere near the speeds and temperatures they're designed for.

Stuff them full I say. Drag and slip exist it theory but I don't see it impacting your ride.

This was for a pivot bearing. The seals I lifted are on the inside, so they'll be less in the firing line for spray from the rear wheel.

Pulling the seals has to be done carefully but it won't cause any damage if you're competent and use the right tool (dental pick, in my case, ymmv). I tested the theory by doing one side of some front wheels but not the other and it's open and shut tbf.

It's not so much that the bearings don't have enough grease, it's just that they're not necessarily designed for our purpose- full filled bearings aren't right for most industrial or high speed processes, while for us keeping crap out and stopping corrosion is important.

Up until now, I’ve tended to believe manufacturers when they claim their bearings are packed full of grease, but having lifted the seals on a couple of brand new Enduro bearings this morning, the covering seemed a bit miserly.

This was for a pivot bearing.

Do you trust Enduro / SKF etc. or t'internet?
99.99% (or deffo a lot) of bearings are made for industrial applications where life is critical and there is competition.. much as it's a faff replacing pivot bearings it's not shutting down a production line.

There are also lots of fake bearings (apparently)... but if you are getting a quality industrial manufacturer I'd trust their fill... I'd also not mix greases.. so when I do repack I clean them out completely first.

Used a curved canvas needle, seemed to do the job without too much fuss.

It’s not so much that the bearings don’t have enough grease, it’s just that they’re not necessarily designed for our purpose- full filled bearings aren’t right for most industrial or high speed processes, while for us keeping crap out and stopping corrosion is important.

Surprised that suspension bearings marketed at MTBers are so stingy with the grease, though.

Anyone found a make that didn't need topping up when you pulled the seals?

My experience (based on LBS work evidence) is that failed bearings have **** all grease in them. Also it seems clear to me that seals aren't damaged if you remove them carefully.

Fill your boots is my advice.

Fill your boots is my advice.

<Goes out to buy more grease>

Cheers everyone, we'll see how long this set lasts...

martinhutch
Subscriber

Surprised that suspension bearings marketed at MTBers are so stingy with the grease, though.

Not too surprised with Enduro personally, haven't used their kit for a while but the shimano BB kit they did was proper shit.

99.99% (or deffo a lot) of bearings are made for industrial applications where life is critical and there is competition

Filling bearings with grease if they're rotating at speed in a dry factory would be both unnecessary and inefficient. But if you could find industrial bearings made to rotate at slow speeds in a wet and muddy environment, I think they'd be full of grease. I would put less grease in a wheel bearing than a pivot.

I generally top mine up - never regretted it yet and it’s quite a satisfying job...

But if you could find industrial bearings made to rotate at slow speeds in a wet and muddy environment, I think they’d be full of grease.

Erm.. so would a mud pump be wet and muddy? Not to mention usually alkaline...
Same goes for ESP's (electrical submersible pumps) often rated to 20k psi and 220F

I don't care about drag on my bike... in fact I usually use PM600 for repacks and most parts apart from pawls and moving suspension surfaces... but overfilling is just pushing the seals off.

Pumps and motors, muddy and submerged or not, soon a little faster than my hubs.

We're also talking about filling bears, which is different from over filling them.

Onzadog, just what are you filling the bears with? 😉 🐻 🛢 🐻 🛢

I used to be a seal lifter but now I buy Blueseal bearings from Trail-vision on ebay. He packs them full with Mobil blue waterproof grease. Inexpensive, last ages and save me risking the seals. I never liked mixing greases anyway, tough to know what grease is in a bearing and odds on it’s not a high quality waterproof in there when you buy it.

My bearings get "kluberluffa" greased.

For no other reason than we use it in a high stress 50rpm muddy environment ......*

I've not had to replace a bearing thats had that grease put in it.

When you look up the price you'll realise why it's not in all bearings.

* One 1/3rd tube assigned per tool. If your not a ham fisted oaf it only needs 1/4 tube to fully fill the tool. Remainder to go in oily waste.....or my wheels

Onzadog, just what are you filling the bears with?

Frozen sausages works best

I'm in the fill 'em up camp. Especially any kind of sram bb.

Here's a copy/paste of my post/rant on a previous thread on the subject:

+1 for enduro bearings being massively overrated. We’d never dream of using them in my industry (marine ship systems). I’d always specify SKF or FAG. I also like hope bearings from a mountain biking viewpoint. Anyone know who the OEM for them is?

For any mountain bike bearing, the main cause of failure is corrosion from water/mud ingress. Apart from a very well sealed hub bearing, I’ve never seen a bearing failure arising from standard wear to the balls/races. Every frame bearing I’ve ever pulled has had more mud than grease inside by the time it’s failed.

With the cavet I’ve never used them, I can’t see much benefit from the Black Oxide bearings. The balls aren’t coated for starters, and they subsequently can corrode and bind to the cage and race. I’d also have questions over the wear resistance of the black oxide coatings on the races. Frame bearings are constantly subjected to non-linear radial and axial loads which really isn’t good for bearing longevity and I can’t see the coating lasting in these conditions.

The best way to keep any mountain bike bearing going is to repack them from new with a decent marine grease. Most bearings have around a 30% grease fill, because more than that increases friction significantly, which matters when on a rotating piece of machinery at 1000rpm, but not a frame bearing that never completes a full rotation. Even enduromax bearings which have been designed for frame bearings aren’t sufficiently filled imo.

The full compliment bearings are a great idea in theory as most frame bearings are undersized for the load conditions. But again corrosion is the usual failure mechanism, and they need a small grove in the side of the race to fit the balls into the bearing during manufacture. This provides a weak point in the sealing interface and further enables water ingress.

A slightly different approach to this is done by a farm lad I know, he protects bearings at work in difficult environments by smearing a liberal coating over the outsides of the seals and bearing seats to prevent the ingress of foreign matter, this has the added benefit of keeping the seating area clean and rust free for the next inevitable replacement. He does the same on his bikes.He has a lot of greaseable bearings at work and says over greasing is a major reason for failures due to seals being popped off through zealous pumping of grease to compensate for negligent maintenance , not applicable to mountain bikes obviously, probably power washing is more to blame, I know it is with one of my mates who has more rusted bearings than an old slurry spreader.

The best way to keep any mountain bike bearing going is to repack them from new with a decent marine grease

I have done this on all my bikes for years.
As said above,the rotations are never close to what high speed machines do.
Removing the seals is not hard,you just have to take care and remember the scale of force needed.;-)

Some great info on here, thanks very much.

When folk are filling bearings, are you just using a needle grease gun, spinning the bearing and filling until you can't get more in?

I've always felt like i never manage to get them properly full.

Needle grease gun or just fill it up by pressing in with my fingers then putting the seals back on and excess grease should be pressed out. I use marine grease, can't remember the brand name, Bell perhaps?

I top up all bearings but I think it's even more important on pivot bearings as there is only a very small angle of motion.

Some, even quality bearings, are virtually empty of grease.