Are Actual SEALED bearings Available?

[bertsmobile1]

There is no such thing as a "fully sealed bearing" apart from custom bearings made for specific tasks and you will not find any of them on a lawnmower $$$$$$
A RS ( Rubber Sealed ) bearing has a GREASE SHIELD to prevent grease getting out easily but as the lip has no strengthening spring it is pretty poor at the job
A ZZ bearing has debris guards on the bearing to prevent gunk getting into the bearing and they are meant to be fitted into a housing that has grease in it so as you add more it forces the old grease out.
These may have a second seal outside the bearing to prevent water getting in .
Interesting chart but totally irrelevant unless they specify the bearing manufacturer and the grease used and more importantly the suspension medium used for the grease
It also ignores temperature which will break down the grease faster
Most bearings from China come with transport grease which is very similar to assembly lube and just there to stop the surfaces rusting before you buy the bearings
And yes you can put too much grease into a sealed bering but it is a lot harder to do with a ZZ because excess will simply exude from the hole in the shield during use which is why I use ZZ where ever possible to replace RS because RS bearing are just too much trouble & require too much work fitting .
And if you has stopped to think about it for a second or two why would any mechanic go to the effort of popping a seal washing out the old grease & replacing it with better quality grease if they could just wack in a untouched bearing for the same price .
We do it for a reason and the reason is we do not want the customer back each & every season with stuffed spindle bearings
So caster fork bearings be they radial or tapered rollers get high tack grease so it does not all end up on the bottom with no grease on the top
I use a Lithium Soap grease with Molly usually a 3 grade
The wheels get a low tack Lithium soap grease usually 2 grade
Blade spindles get a high temperature EP lithium grease again grade 2
I am about to go over to a lanolin grease for casters which is low melt
All are marine grade greases because mowers get exposed to a lot of weather

I have just added a Ferris IS600 to the servicing fleet and they specify a Calcium Solfonate grease for the casters & the yokes so I am debating if I really need to add yet another type of grease as I stock 7 at the moment or if I should just wash out all of the Calcium grease & use the std Lithium .
OIls ain't oils Sol
&
Greases ain't just grease

 

[Forest#2]

To the Original Poster (OP): shielded vs sealed or ZZ vs RS
You can find lots of info on-line about shielded vs sealed bearing. (or z vs zz vs RS vs 2RS.
Here is just one link that eventually indicates that 2RS sealed type bearings might be better in some lawn mower applications. (2=sealed both sides, R=rubber, S=Sealed)

ZZ vs. 2RS Bearings: Key Differences for Optimal Selection

When you're dealing with machinery, every tiny component counts, especially when it's about bearings. ZZ and 2RS bearings may look similar, but they serve your equipment in distinct ways. Understanding the difference can save you time and money, and ensure your machinery runs smoothly. You might...

www.allinthedifference.com

 

[tgzzzz]

Excellent and very helpful post, Bert. Thanks. I did run into a short bit re actual steel-sealed ball bearings and it said while they were not serviceable, they had a life span of around 3 years in presumably 24-7 service. That's what I was hoping to buy. For a mower, that would be a buy once, cry once deal that I'd pay for. Good info on the ZZ shields. I'm switching from Rs and have some Timken ZZs on order from Amazon. I hope they really are genuine Timkens.

 

[tgzzzz]

Just something to think about:
This also really does not answer your question about if the seals actually seal the bearings.
BUT what I've seen is: (Im referring to roller bearing of the type you refer to, not timken tapered bearings.
In last few years for NEW replacement lawn tractor bearings for my own equipment I prefer the plastic seals type so as I can pop out the plastic sealand pack the bearing with new grease because I see several new bearing have little to no grease when new. I pack the new ones and when inspecting a used bearing if it's still running smooth, especially spindle deck bearings I pop the seal, clean, re-pack and re-install the seal. (and also idler pulley seals if I can grease them from the lower side and get a good re-seal of the plastic seal. If the spindle has a Zerk I sometimes leave the Zerk facing side of the bearing open to receive grease BUT main thing is I repack them.
I'm not convinced that on a mower deck spindle that the bearings are receiving non-contaminated grease from the zerk spindle. The grease in the spindle housing might just be a heat sink and actually eventually takes on some contaminants and does more harm than good? (I cannot tell any difference in the life of a spindle deck bearing that I've re-packed and re-installed the plastic seal vs leaving the seal off and using the zerk and thinking I'm really doing a good thing when adding more grease later)
If the seal has the one plastic seal on the opposite side of the bearing from the spindle zerk the seal can be pushed/blowed out from applying too much grease.

Thanks for this too, sir. Love real world evidence. As you note, pressure can pop the rubber seal out ... I have the same distrust of the zerked spindle. A benefit of the ZZ shield is that pressure just forces grease out ... as designed. A nice distinction.

 

[tgzzzz]

To the Original Poster (OP): shielded vs sealed or ZZ vs RS
You can find lots of info on-line about shielded vs sealed bearing. (or z vs zz vs RS vs 2RS.
Here is just one link that eventually indicates that 2RS sealed type bearings might be better in some lawn mower applications. (2=sealed both sides, R=rubber, S=Sealed)

ZZ vs. 2RS Bearings: Key Differences for Optimal Selection

When you're dealing with machinery, every tiny component counts, especially when it's about bearings. ZZ and 2RS bearings may look similar, but they serve your equipment in distinct ways. Understanding the difference can save you time and money, and ensure your machinery runs smoothly. You might...

www.allinthedifference.com

That was a good read.