So I’ve understood that on receipt of a new sealed bearing, it is usually good to remove the seal, pack the bearing with additional grease and re-seal. This has been told to me working on bicycles and motorbikes.

However, came across Hambini website – some really interesting stuff on there and this is what he says re greasing bearings:

“It is very important to prevent overfilling of bearings. Only 33% of the unoccupied volume is required to be filled, it does not and should not be packed fully. Doing so will cause the bearing to overheat and lead to premature failure. It also increases friction exponentially. As the bearing rolls, the grease heats up and it turns into a semi oily mixture, over time this will leak out of the seals so they will need repacking.”

So is a lightly greased/filled sealed bearing correct Vs stuffing it with grease?

He is right in some applications although I doubt a bicycle will generate enough force to overheat bearings.

personally However I never repack bearings – IMO all you are doing is wrecking the seals and that leads to water penetration and bearing failure ( slowed by the extra grease)

others will disagree

I repack with marine wheel bearing grease (£8 for 500ml), after using a #11 scalpel blade to carefully remove the seals, then to reseat seals after #surgery. Except with Hope bearings as they actually seem to last.

Overpacking is only a problem for bearings that spin fast. I pack frame bearings, but not wheel bearings. And I don’t pedal fast, so I also pack BBs.

I dont touch new bearings because of the risk of damaging a perfectly good seal but I do sometimes repack them when I do the 6 monthly stripdown/service – willing to take a chance then.

Removing seals without damage doesn’t seem like rocket science to me.

And any bearing I’ve replaced has been corroded with a tiny amount of grease in it.

They are made for industrial high speed applications where there is little risk of water exposure – nothing like mtbs.

Pretty much as above. I won’t do a new one but will happily repack after a bit of use. Any slow moving ones can be well packed. That said nothing on a bike spins very fast by bearing standards. I have just packed some hub bearings to get some more life from them.

EFF Hambini, hes a total dick bicycle bearings wont get hot enough.
Pry them off fill them with marine grease and install with the seal you removed facing inwards.

Only really check to make sure it’s not a dry bearing being fitted, as sometimes you get them like that new.

IMO all you are doing is wrecking the seals

Seal picks cost pennies, nothing needs to get wrecked

Logical brain tells me Hambini might be right. Experience tells me he’s not – always repack mine including new ones and they seem to last a lot longer…

So many new bearings arrive almost dry inside and it’s ridiculously easy to remove a seal without damaging it.

Why wouldn’t you at least take a peak?

mtb & commutah – pack
road – don’t bother (not for the extra speed 🤓, just CBA and I don’t roady in the rain/mud/gritty shite)

Any bearing I can get to easily gets a smear on the outside, between the seal and the shield (if there is one)

All bike bearings are co-opted from pre-existing industrial supply. They are designed to run at high rpm and all of Hambinis advice is relevant for that environment and use.

It’s obvious that on a bike – which is low rpm use – that if one packs a bearing completely the friction goes up – its easy to feel. In competitive road cycling I can imagine this would be considered a factor.

But, my experience of this in use is that after a short period, a bearing pushes out the grease it doesn’t need through the seal. After this, theres barely any difference in friction, but you can guarantee that the bearing is as full as it can be.

Seals. Its a rubber coated washer with a flexible lip that sometimes nests in a tiny groove, and sometime just touches the edge of the inner/outer race.

Sure, if you’re a ham fisted oaf its easy to damage a bearing seal, but equally its not especially difficult to prise them out undamaged.

Personally, I’m sure I get more bearing life when I pack from new. Virtually all by mtb bearings die from water penetration and corrosion. Decent aftermarket grease prevents this better than the stock fill, and a filled bearing has less void space to allow water to accumulate.

I’ve done it for years, small scalpel blade on the inside edge, repack with Rocol Sapphire 2. Guess what, I get much longer bearing life than friends who live and ride in the same area.

I don’t pay much heed to Hambini tbh – he’s a dick who seems to only think/operate in the hypothetical lab conditions where he can do his maths. I think there’s a lot less “real world” value to a lot of what he says. As I see Jacy Shumilak repacking bearings from new, I’m more inclined to go with him than Hambini.

Oh yeah, I forgot to add this to my post so for the sake of completion….

Hambini is a milspec rotwomble.

I always clean out factory grease (unless it’s the same) and repack with marine grease.

There is a guy on here that knows a LOT about bearing usage as it’s part of his job, he agrees that on bikes repacking is the way to go. Its high rpm use that it might be an issue, not on bikes.

I practiced removing the deals on a couple of old bearings needle doing it on new ones, it’s very easy tbh.

thanks all … interesting and will continue to pack!

All bike bearings are co-opted from pre-existing industrial supply.

Hope/INA say otherwise
(not saying you’re wrong they might be lying but I don’t think so because *)

In general I reckon companies like SKF or INA who spend millions on bearing research probably know better than I do.

*Given Hope make a big deal about INA custom making and filling their bearings it makes no sense to then save pennies on grease vs reputation.

I think the most important thing is what bearings are you buying?

If original hope bearings or other high expensive ones the no need to touch them on first installation.

However, if your buying cheap ones or forgeries then it’s worth opening to have a look.

I find most frame bearings are usually stuffed and it’s a time consuming job so I just replace.

My hope ceramic bb has been cleaned and regressed countless times, never had a problem or noticed a difference.

Yorkshire grit and winters are hard on bikes and I’m not a fan of spending money when I can repair something.

I’ve had Hope bearings arrive with very little grease on occasion. You unfortunately dont know the “fill” till you open them up, whatever brand it is.

I think the most important thing is what bearings are you buying?

If original hope bearings or other high expensive ones the no need to touch them on first installation

This is such a naive thing to think I don’t really know what to say.

I do, it works- I’ve a/b tested twice with a repacked bearing in one side of a front hub and a standard one in the other and both times the unpacked one was crunchy while the packed one was still smooth. Obviously some applications stress or expose the different sides differently which is why I did it twice, in the same design hub. Anyone can do the same, it’s not hard to safely remove a seal.

You can definitely feel the difference in your fingers, and you can see it in a wheel in the stand but feel it on the trail? I don’t believe so. it takes a fingertip push to spin a wheel in a stand, that doesn’t move a whole bike and rider even an inch.

stevextc
Free Member

*Given Hope make a big deal about INA custom making and filling their bearings it makes no sense to then save pennies on grease vs reputation.

I’ve opened up quite a few brand new Hope bearings (or rather INA sold by Hope, it’s usually a pretty cheap way to buy good bearings) and the amount of grease varies wildly. Not sure if there’s a pattern to it, like maybe some bearings are filled more than others intentionally, but I think all the wheel bearings have been filled much the same as any standard bearing. Not certain. It may be a different grease.

Anyway, I put more grease in ’em.

Yay

All bike bearings are co-opted from pre-existing industrial supply. They are designed to run at high rpm

Not sure this is true. Those Enduro Max ones have a long spiel about how they are specced for MTB suspension use and are packed with grease and have an extra bearing. There is no wiggle room in there description so if this incorrect then they’d have to be flat out lying.

We also have the solid grease bearing from whoever it was, again a bike specific product.

We also have the solid grease bearing from whoever it was, again a bike specific product.

I thought they were developed for use in sterile environments like labs and food preparation?

Northwind

I’ve opened up quite a few brand new Hope bearings (or rather INA sold by Hope, it’s usually a pretty cheap way to buy good bearings) and the amount of grease varies wildly.

Fair enough .. I usually wait TBH.
When I do repack

You can definitely feel the difference in your fingers, and you can see it in a wheel in the stand but feel it on the trail? I don’t believe so. it takes a fingertip push to spin a wheel in a stand, that doesn’t move a whole bike and rider even an inch.

I use PM600 … and I’m sure it spins less in the stand but as you say can I even feel that on the trail? If I wanted them to spin fast in the stand I’d remove the covers and grease and just spray with some silicone based light oil… be brill for about 10m mins. 😉

We also have the solid grease bearing from whoever it was, again a bike specific product.

Think your referring to the CC ones ??